Dissertations / Theses: 'Bio-based material'

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RAJABINEJAD, HOSSEIN. "Keratin Based Material For Perspective Bio-Application." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2697565.

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Keratin has natural characteristic for applying in biomaterial field as a biocompatible matrix like tissue regeneration, proliferation, and cell adhesion or drug career in the shape of microcapsules or microsphere. Because of the amino acid inherent structure, keratin extraction needs to be well designed to meet the particular requirement for applying in desired applications such as integrate with different molecules, drug releases, wound healing or biocompatible film. Keratinous sources such as wool, feathers are valuable by-products that abundantly present in nature. Although wool has valuable material in especially in textile industry, massive amount of low-grade wool cannot be utilized in textile and inevitably end up as a waste stream. Because of high cystine content of keratin, solubilization and extraction of keratin is a problematic process compared with other natural polymers such as collagen and chitosan. Using keratin in different level especially in large-scale requires understanding final properties of keratin which is strongly depends on producing procedure.. The interest towards drug career and microcapsules based on non-toxic, biodegradable and biocompatible polymers, such as proteins, is increasing considerably. In this work, keratin from wool fibers was extracted with oxidation, reduction, sulfitolysis, and superheated water hydrolysis methods. The effect of each method on obtained keratin properties are discussed and particularly reported how each extracted keratin influenced by the extraction process. In particular, all different samples of extracted keratin were characterized by molecular weight determination, FT-IR and NIR spectroscopy, amino acid analysis, and thermal behavior and the archived data were compared with reporting of previous studies with the emphasis of advantage and limitation of each extraction method. In the other part of the study, special attention are given to produce microcapsule and film from keratin-based material in line with biomaterial application. Microcapsules were prepared using water-soluble keratin, known as keratoses, with the aim of encapsulating hydrophilic molecules. The obtained keratin via oxidizing extraction of pristine wool, were utilized as shell part of the microcapsules which produced by sonication method. Production of the microcapsules was carried out by a sonication method. The microencapsulation and dye encapsulation yields were obtained by UV-spectroscopy. In addition, morphological structure of microcapsules was studied by light microscopy, SEM, and AFM and thermal properties of microcapsules were investigated by DSC. The molecular weights of proteins analyzed with gel-electrophoresis indicates the extracted keratoses has suitable molecular weight range for bio-application, and also the results confirmed that the hydrophilic dye (Telon Blue) was introduced inside the keratoses shells. The final microcapsules diameter ranged from 0.5 to 4 µm. One part of the experimental work is dedicated to producing keratin blend film with polyvinyl alcohol (PVA). PVA has been chosen because of its biocompatible and biodegradable properties which make this polymer as a promising candidate in the bio-field area. Blend of Polyvinyl alcohol (PVA) and keratoses were prepared with the aim of producing bio-compatible material proper for film and fiber structure mainly to improve the mechanical properties of obtained keratoses. Aqueous solution of keratoses and PVA was prepared for solution casting method. Blended films were characterized by, SEM, FT-IR spectroscopy and Differential scanning colorimetry and tensile properties.

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Carbone, Christopher M. (Christopher Martin) 1975. "Mainstreaming straw as a construction material : understanding the future of bio-based architectural materials." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/64914.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2003. Includes bibliographical references (p. 143-158). There is a current trend in design and construction towards the use of distinct prefabricated components in the production of buildings. There is also a growing awareness by architects and builders of the environmental impact caused by the production, operation, and disposal of buildings. Since the industrial revolution, building materials have tended towards high-energy solutions, as materials of renewable origin are inherently difficult to manufacture to the tight tolerances demanded from modern design. Additionally, they are perceived as more susceptible to fire and rot than many synthetic materials. Yet, impending energy shortages as well as environmental concerns now force us to reconsider if there are ways to use renewable materials without compromising design. One such material worthy of reconsideration is straw; which has been used for thousands of years in architecture. Straw refers to the dried stems of grain bearing grasses, which are often burned or tilled back into the soil after the grain has been harvested. This paper will survey the current global production of straw and the environmental impact of straw use in construction. Further, it will identify future opportunities for the use of straw in modern design. Included is a design for a straw insulation system for commercial architecture. The system is comprised primarily of straw with a bio-based shell. This insulation system is designed for disassembly from the other building systems so that these organic materials can return to their natural cycles at the end of the use phase. A sample design is given to demonstrate its use in construction, and prototypes are built to test the feasibility of this design. Computer simulations are performed to demonstrate hygro-thermal response of this design to the climates of Boston, Massachusetts; Minneapolis, Minnesota; and Los Angeles, California. Preliminary thermal testing of the prototypes qualitatively indicates their effectiveness. The analysis is then expanded to a discussion of the link between global waste generation, resource consumption, and life spans of building systems. Finally, a simple method of classifying natural resources is presented which may help educate future generations to better understand the full ramifications of design and development, and a life cycle analysis of the designed component is performed using this new classification scheme. by Christopher M. Carbone. S.M.

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PIRANI, FEDERICA. "Bio-oriented Micro- and Nano- Structures Based on Stimuli-responsive Polymers." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2706874.

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Nowadays, the ability to pattern surfaces on the micro- and nano- scale is the basis for a wide range of research fields. Over last few decades, a lot of processing technologies offer the possibility to fabricate complex 2D and 3D polymeric designs which are mostly static in nature since they cannot be physically and chemically modified once fabricated. The aim of the present thesis is to overcome such a limitation, exploiting stimuli-responsive materials (Chapter I). We allow to engineer polymeric architectures adding interesting functionalities, by providing an active manipulation of pre-structured systems, which could be helpfully in a wide variety of applications, such as biosensing and cell conditioning. In the first part of the present dissertation (Chapter II), a thermos-sensitive material is employed. We investigate the thermo-responsive behavior of Poly(N-isopropylacrylamide) (pNIPAAm)-based crosslinkable hydrogel as active binding matrix in optical biosensors. In this study, we propose an extension of surface plasmon resonance (SPR) and optical waveguide mode (OWS) spectroscopy, for in situ observation of nano-patterned hydrogel film that are allowed to swell and collapse by varying the external temperature of the aqueous environment. Weak refractive index contrast of hydrogel structures arranged in periodic pattern, is generally associated with intrinsically low diffraction efficiency. In order to enhance the intensity of diffracted light, the surface is probed by resonantly excited optical waveguide modes, taking advantage of the fact that the hydrogel can serve as optical waveguide (HOW) enabling the excitation of additional modes besides surface plasmons. Thus, we provide a hydrogel optical waveguide-enhanced diffraction measurements, taking advantage of strong electromagnetic field intensity enhancements that amplifies the weak diffracted light intensity. The main part of the thesis is focused in the study of azopolymer-containing materials, a specific class of light-responsive materials. Upon photon absorption, azobenzene undergo reversible trans-cis photoisomerization, which induces a substantial geometrical change of its molecular structure, that can be translated into larger-scale movements of the material below the glass transition temperature (Tg) of the polymer. In Chapter III, by exploiting the light-induced mass migration phenomenon, we demonstrate that an azopolymeric film patterned by soft imprinting technique, can be anisotropically deformed and consequent restored in its initial shape via single irradiation just by controlling the polarization state of the incident laser beam. We also propose that the light-driven morphological manipulation can induce anisotropic wettability changes. Lastly, a polarization driven birefringence effect on flat and structured surfaces is discussed. Chapter IV focuses in the design of novel azopolymeric systems, where the optical response is provided by azobenzene molecules, which doped two different host materials. The photo-responsive behavior and potential applications of azo compounds incorporated into either a soft elastomeric and in rigid matrix is discussed. Azo-embedded poly(dimethylsiloxane) (PDMS) is studied as tunable optical lens and an azo-doped photocurable commercial polymeric resin is developed to study the photo-mechanical transduction of a 3D suspended membrane fabricated by two photon lithography technique. In Chapter V, we propose a light-deformable azopolymeric micro-pillars patterned substrate as a biocompatible and “smart” platform for dynamic material-cell observation in 2D environment, modified by a holographic optical conditioning. The aim is to observe by time-lapse acquisitions, how an in situ deformation of a pre-patterned structure can influence cell functions and fate. Finally, in Chapter VI, general remarks of the present work are discussed, and directions for future perspective are summarized.

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Coste, Benoît. "Possibilities and limitations for a bio-based composite to be used as speaker cabinet material." Thesis, KTH, Maskinkonstruktion (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-170800.

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Nocs är en svensk tillverkare av hörlurar och högtalare. Marknaden har förändrats för ljud produkter då det idag är det en större kundgrupp som efterfrågar ljudrelaterade produkter med hög kvalité och som är miljövänliga. I denna förändring av marknaden finns en ekonomisk potential för Nocs vilket har lett till att Nocs överväger att ha bio-komposit som material i deras högtalarlåda som ett alternativ till den nuvarande MDF.Beställaren av projektet, Innventia, arbetar med utveckling av träfibermaterial och har accepterat att utreda möjligheter och begräsningar med användandet av bio-komposit i högtalarlådor åt Nocs.En högtalarprototyp har tillverkats i bio-komposit genom formpressning på Innventia och KTH. Fysikaliska och mekaniska egenskaper av bio-kompositen har utvärderas hos Innventia och prototypen är testad hos Nocs. Parallellt har en användarcentrerad approach implementerats för att identifiera användarnas behov gällande högtalare.Subjektiva ljud tester på referensprototypen och den formpressade prototypen uppvisade likande ljudprestanda. Dragprovning på formsprutade standardprovkroppar tydde på att ett motsvarande resonansbeteende kan förväntas för en formsprutad prototyp. Kostnader och led-tider bevisas inte förbättras med formpressning i denna studie. Miljöpåverkan vid tillverkning av bio-komposit är också rapporterad att vara högre än vid tillverkning av MDF material i ett flertal kategorier, däremot finns ett behov av ytterligare studier för att bekräfta detta. För användarna är materialet inte lika viktigt som utseende, ljudprestanda, användarvänlighet och funktioner för anslutning. I enlighet med de uppfattningar, vanor och behov som identifierats har ett högtalarkoncept utvecklats.Sammantaget har denna studie bekräftat relevansen av att använda en bio-komposit i en högtalarlåda avseende ljudprestanda och genomförbarhet. Ytterligare arbete behöver genomföras för att utvärdera den faktiska lönsamheten och miljöpåverkan denna lösning skulle ha för Nocs. Användarbehov har identifierats och är till grund för ett föreslaget relevant högtalarkoncept. Nocs is a Swedish manufacturer of audio products. With the rise of demand in high quality and user-friendly audio equipment, the economic potential of Nocs’ products is big. To face competition, Nocs has been thinking about bio-composites as an alternative to their current Medium-Density Fiberboard (MDF) material solution.Innventia, the commissioner of this project, works with innovation based on forest raw materials and has accepted to investigate possibilities and limitations for a bio-based composite to be used as speaker cabinet material.For this purpose, a loudspeaker prototype has been made in bio-composite by compression-molding at Innventia and KTH. Physical and mechanical properties of the bio-composite of interest have been evaluated at Innventia, and the prototype tested at Nocs. In parallel, a user-centered product development approach has been implemented to identify users’ needs in terms of speakers.Subjective sound testing exhibited similar sound performance between the compression-molded prototype and the reference loudspeaker from Nocs. Tensile testing on injection-molded standard test specimens suggested that equivalent resonance behavior could be expected for an injection-molded prototype. However, no clear evidence could ensure cost and lead-time would be reduced with such a process compared to Nocs current solution. Environmental impact for producing bio-composite is also reported to be higher than for MDF in several categories, but further analysis would be needed to confirm this. From users’ perspective, importance of material is globally overwhelmed by look, sound performance, usability, and connectivity features of loudspeakers. In accordance with users’ perceptions, habits, and needs, a loudspeaker system concept has been created.Overall, this study has confirmed relevancy of the bio-composite to be used as a loudspeaker cabinet, as regards sound performance and feasibility. Further work must be done to evaluate actual profitability such a solution can bring to Nocs, and related environmental impact. Users’ needs have also been identified to propose a relevant loudspeaker concept.

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Gribbling, Emil. "Biobaserade material i fotbollsbenskydd." Thesis, Mittuniversitetet, Avdelningen för kvalitets- och maskinteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39670.

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I takt med att fossila resurser begränsas och allmänhetens krav på miljövänliga alternativ ökar, har utvecklingen av biobaserade plaster tagit fart. Nya framsteg i form av fler material, innovativa tillverkningsprocesser och förbättrade egenskaper har gjort att applikationsområdet nu sträcker sig från engångsartiklar med krav på nedbrytbarhet, till tekniska och ingenjörsmässiga applikationer. Syftet med arbetet var att undersöka möjligheterna för företaget Flaxta att använda biobaserade polymerer vid tillverkning av fotbollsbenskydd. Ett klassiskt fotbollsbenskydd består av ett hårdare yttre skal i termoplast tillsammans med en mjukare insida i skumplast. Målet var att identifiera biobaserade polymerer som kan ersätta de fossilbaserade polymerer som idag används vid tillverkning av benskydd för fotbollsspelare. Undersökningen av material utifrån begränsningar på biobaserat innehåll visade att det finns flera biobaserade termoplaster som är identiska med deras konventionella fossilbaserade varianter och direkt kan sättas in i befintliga produktionssystem. Dessa material har goda förutsättningar att ersätta de material som idag används i fotbollsbenskydd. Biobaserade termoplastisk polyuretan (TPU) och polyamid (PA 11) identifierades som de två mest lämpliga termoplasterna för att ersätta befintliga benskyddsmaterial. En övergång till biobaserad TPU skulle kunna minska koldioxidavtrycket vid primärproduktion med 36 % jämfört med fossilbaserad TPU. PA 11 är 100 % biobaserad och släpper ut betydligt mindre koldioxid i atmosfären vid primärproduktion jämfört med flera fossilbaserade polyamider. Undersökningen av biobaserade skummaterial resulterade i att etenvinylacetat (EVA) från företaget Braskem har potentialen att ersätta fossilbaserad EVA och polyuretan (PU) som idag används som mjukt energiabsorberande skummaterial i benskydd på marknaden. Valet av material tillsammans med benskyddets geometri och design utgör benskyddets skyddande egenskaper. Därför krävs ytterligare tester och analyser av benskydd tillverkade i de biobaserade materialen för att säkerhetsställa att kraven på stötdämpningsförmåga uppnås. In response to the reduction of fossil resources and increasing public demands for environmentally friendly alternatives, development of bio-based plastics have accelerated. New advancements in the form of more materials, innovative manufacturing processes and improved properties mean that the application area now extends from disposable products with the requirements of biodegradability to products for technical and engineering applications. The purpose of this work was to investigate if the company Flaxta could use bio-based polymers when developing shin guards for football players. A classic shin guard is made out of a thermoplastic outer shell together with a softer inner foam material. The aim was to identify bio-based polymers that could replace fossil-based polymers currently used when developing shin guards. The study of bio-based materials showed that there are several thermoplastics that are similar to the petrochemical plastics and can be directly inserted into existing production systems. These materials have good potential to be used as environmentally friendly alternatives to the current materials in shin guards. Bio-based thermoplastic polyurethane (TPU) and polyamide (PA 11) were identified as the two most suitable thermoplastics to be used in shin guards. A transition to bio-based TPU could reduce the carbon footprint from primary production by 36% compared to fossil based TPU. PA 11 is 100% bio-based and emits significantly less carbon dioxide in the atmosphere during primary production compared to several fossil-based polyamides, therefore does not contribute as much to climate change. The study of bio-based foam materials showed that ethylene vinyl acetate (EVA) from the company Braskem had the potential to replace the fossil based EVA and polyurethane (PU) which is currently used as soft energy absorbing materials in shin guards on the market. The choice of material together with the geometry and design make up the protective properties of shin guards. Therefore, further tests and analyzes of shin guards made out of the bio-based materials identified as potential replacements are required to ensure that the standards for shock absorptions are met. Betyg 2020-07-07

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Adekunle, Kayode. "Bio-based Composites from Soybean Oil Thermosets and Natural Fibers." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3587.

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In order to reduce over-dependency on fossil fuels and to create an environment that is free of non-degradable plastics, and most importantly to reduce greenhouse gas emission, bio-based products are being developed from renewable resources through intense research to substitute conventional petrochemical-based plastics with renewable alternatives and to replace synthetic fibers with natural fibers. Many authors have done quite a lot of work on synthesizing polymers from renewable origin. Polylactic acid (PLA) has been developed and characterized, and it was found that it has enormous potential and can serve as an alternative to conventional thermoplastics in many applications. Modification of the plant oil triglycerides has been discussed by many authors, and research is still going on in this area. The challenge is how to make these renewable polymers more competitive in the market, and if possible to make them 100% bio-based. There is also a major disadvantage to using a bio-based polymer from plant oils because of the high viscosity, which makes impregnation of fibers difficult. Although natural fibers are hydrophilic in nature, the problem of compatibility with the hydrophobic matrix must be solved; however, the viscosity of the bio-based resin from plant oils will complicate the situation even more. This is why many authors have reported blending of the renewable thermoset resin with styrene. In the process of solving one problem, i.e reducing the viscosity of the renewable thermoset resin by blending with reactive diluents such as styrene, another problem which we intended to solve at the initial stage is invariably being created by using a volatile organic solvent like styrene. The solution to this cycle of problems is to synthesize a thermoset resin from plant oils which will have lower viscosity, and at the same time have higher levels of functionality. This will increase the crosslinking density, and they can be cured at room temperature or relatively low temperature. In view of the above considerations, the work included in this thesis has provided a reasonable solution to the compounded problems highlighted above. Three types of bio-based thermoset resins were synthesized and characterized using NMR, DSC, TGA, and FT-IR, and their processability was studied. The three resins were subsequently reinforced with natural fibers (woven and non-woven), glass fibers, and Lyocell fiber and the resulting natural fiber composites were characterized by mechanical, dynamic mechanical, impact, and SEM analyses. These composites can be used extensively in the automotive industry, particularly for the interior components, and also in the construction and furniture industries. Methacrylated soybean oil (MSO), methacrylic anhydride-modified soybean oil (MMSO), and acetic anhydride-modified soybean oil (AMSO) were found to be suitable for manufacture of composites because of their lower viscosity. The MMSO and MSO resins were found to be promising materials because composites manufactured by using them as a matrix showed very good mechanical properties. The MMSO resin can completely wet a fiber without the addition of styrene. It has the highest number of methacrylates per triglyceride and high crosslink density. Akademisk avhandling för avläggande av teknologie doktorsexamen vid Chalmers Tekniska högskola försvaras vid offentlig disputation, den 6:e maj, Chalmers, KE-salen, Kemigården 4, Göteborg, kl. 10.00.

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CONTI, DANIELE. "Neuromorphic systems based on memristive devices - From the material science perspective to bio-inspired learning hardware." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2711511.

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Hardware computation is facing in the present age a deep transformation of its own paradigms. Silicon based computation is reaching its limit due to the physical constraints of transistor technology. As predicted by the Moore’s law, downscaling of transistor dimensions doubled each year since the 60s, leading nowadays to the extreme of 16-nm channel width of the present state-of-the-art technology. No further improvement is possible, since laws of physics impose a different electrical behavior when lower dimensions are attempted. Multiple solutions are then envisaged, spanning the range from quantum computing to neuromorphic computing. The present dissertation wants to be a preliminary study for understanding the opportunities enabled by neuromorphic computing based on resistive switching memories. In particular, brain inspires technology and architecture of new generation processors because of its unique properties: parallel and distributed computation, superposition of processing and memory unit, low power consumption, to cite only some of them. Such features make brain particularly efficient and robust against degraded data, further than particularly suitable to process and store in memory new nformation. Despite many research projects and some commercial products are already proposing brain-like computing processors, like spiNNaker or IBM’s Bluenorth, they only mimic the brain functioning with standard Silicon technology, that is inherently serial and distinguish between processing and memory unit. Resistive switching technology on the other hand, would allow to overcome many of these issues, enabling a far better match between biological and artificial neuromorphic computation. Resistive switching are, generally speaking, Metal-Insulator-Metal structures able to change their electrical conductance as a consequence of the history of applied electric signal. In such sense, they behave exactly as synapses do in a biological neural networks. For this reason, resistive switching when modeled as memristor, i.e. memory-resistor, can act as artificial synapses and, moreover, are particularly suitable to be interfaced with artificial Silicon neurons that are designed to replicate the biological behavior when excited with electric pulses. Anyhow, from the technological standpoint, there is still no standard on the design and fabrication of resistive switching, so that multiple structure and materials are investigated. In this dissertation, it is reported an analysis of multiple resistive switching devices, based on various materials, i.e. TiO2, ZnO and HfO, and device architectures, i.e. thin film and nanostructured devices, with the scope of both characterizing and comprehending the physics behind resistive switching phenomena. Furthermore, numerical simulations of artificial spiking neural networks, embedding Silicon neurons and HfO-based resistive switching are designed and performed, in order to give a systematic analysis of the performances reached by this new kind of computing paradigm.

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Moudood, A. H. M. Abdul. "Investigation of the Effect of Water and Moisture on the Performance of Flax Fibre Based Bio-Composites." Thesis, Griffith University, 2019. http://hdl.handle.net/10072/390010.

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Flax fibre composite is a bio-material that can meet the requirements in many engineering applications. It has been used especially in applications for the automotive industry due to the several excellent specific properties which are similar to composites manufactured with glass fibres. However, due to the hydrophilic nature of flax fibre, this material is prone to absorb water and moisture from the environment, and therefore, they are not reliable for outdoor applications. The growing demand for flax composites in the field of bio-material research enforces the researchers to have in-depth knowledge in their processing into a useful final product. However, the correlation between the environmental effects and the performance of the flax fibre bio-composites is not well established. The main focus of this study is to address the specific environmental issues and their effects on flax fibre composites manufactured by the vacuum infusion method. First of all, the effect of the moisture content in the fibres on the mechanical performance and overall quality of the manufactured composites is studied. Flax composites are manufactured with fibres having different moisture content and they are compared to composites manufactured with dry fibres. This work begins with measuring moisture absorption kinetics of the flax fibres. Flax fibres absorb moisture almost linearly from 0% to 70% RH (relative humidity) environments, however, this absorption almost double from 70% to 95% RH. The tensile strength of the flax fibre reinforced composites increases until a certain RH value (50% RH) and then it decreases as the RH of the environment is raised up to the maximum value (95% RH). However, the tensile modulus, flexural strength and modulus of the composite samples continuously decrease with the increasing RH values. The microstructural tests of the composites confirmed the presence of micro-cracks and pores and debonding in the fibre-matrix interface. In addition, a study about the dynamic response of the flax composites manufactured with fibres stored at different RH levels ensures that dry composites have better vibration and damping properties. The damping ratios of the flax composites manufactured with fibres with different RH values are slightly increased with the increasing rates of moisture absorption although this change is not notable. Moreover, the mechanical properties of the flax composites manufactured with fibres at different RH environments are predicted by analytical models. The geometric and displacement potential function approaches are proposed to estimate the tensile properties of the flax composites. The proposed models demonstrate greater accuracy when validated with experimental observations. Secondly, the consequence of different environmental conditions on the performance and durability of flax composites is analysed. Composites made by vacuum infusion using dry fibres are immersed in water, exposed to warm humid environments and subjected to freeze-thaw (F/T) cycles. During exposure to different environments, the mechanical performance (tensile and flexural properties), moisture content and physical changes (dimensional stability) of the composites are analysed. The water absorption trend is partially Fickian for the samples immersed in water at room temperature and these samples are greatly affected and degraded. Furthermore, the mechanical properties of the water saturated (WS) samples are clearly degraded in contrast to the as manufactured (AM) samples. Compared to AM samples, the tensile strength and modulus are decreased approximately by 9% and 57%, respectively for WS samples and their flexural strength and modulus is decreased by 64% and 70%, respectively. However, some of these properties could be recovered, to some extent, by drying the WS samples. On the other hand, the reduction of tensile strength and modulus for the humidity saturated (HS) samples is only 0.8% and 3%, respectively, when compared to the AM composite samples. It was found that freezing-thawing cycles have almost no effects on the flax bio-composites. Thesis (PhD Doctorate) Doctor of Philosophy (PhD) School of Eng & Built Env Science, Environment, Engineering and Technology Full Text

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Ilic, Natasa, Nektaria Lalangas, Jowan Rostami, and Alexander Wiorek. "Nya material från protein-nanofibrer." Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-208749.

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Under det här kandidatexamensarbetet har protein-nanofibers påverkan på material undersökts genom att jämföra fibrillerade filmer med ofibrillerade. Sojaproteinisolat fibrillerades under förhållandena pH 2 och 85 ◦C under minst ett dygn och de syntetiserade nanofibrerna analyserades med Thioflavin T (ThT) fluorescens och atomkraftsmikroskopi (AFM). Spektra från analysmetoden ThT fluorescens indikerade på förekomsten av β-flak och analyserna med AFM visade på att fibrerna hade en morfologi som är karakteristisk för protein-nanofibrer. Resultaten antyder att de parametrar som påverkar morfologin hos fibrerna är fibrilleringstid och typ av protein. De gjutna filmerna från fibrillära respektive ofibrillära proteiner var sammanhängande bortsett från vissa sprickor. Värdena på E-modulen från AFM visade att det fibrillerade materialet var mer heterogent än det ofibrillerade. Filmer med sammanhängande yta erhölls vid tillsats av det mjukgörande additivet glycerol. Slutligen, material av både fibrillär och ofibrillär form kan framställas, däremot krävs vidare forskning för att optimera materialens egenskaper. During this bachelor thesis project, the impact of protein nanofibers on materials has been analysed by comparing films made from fibrillar and non-fibrillar protein. Fibrillation of soy protein isolate was performed during at least 24 hours at pH 2 and a temperature of 85 ◦C. Analysis of the nanofibers was made with Thioflavin T (ThT) fluorescence and atomic force microscopy (AFM). The spectra from ThT Fluorescens indicated the presence of β-sheets and AFM confirmed that the fibrils had a morphology that is characteristic of protein nanofibers. The results indicated that heating time and protein type were the parameters which had the largest impact on the morphology of the fibrils. The synthesised films from both fibrillar and non-fibrillar protein were coherent with exception of some cracks. The elastic modulus from AFM indicated that the fibrillar film was more heterogeneous compared to the non-fibrillar film. To attain coherent films, the plasticising agent glycerol was added. To summarise, both fibrillar as well as non-fibrillar materials were successfully synthesised, however, further research is necessary to optimise the properties of the material.

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Sung, Jonggeun. "Design and synthesis of plant oil-based UV-curable acrylates for sustainable coating applications." Diss., Kansas State University, 2018. http://hdl.handle.net/2097/38657.

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Doctor of Philosophy Department of Grain Science and Industry X. Susan Sun A demand in sustainable polymers has been increased because of the environment concerns and saving finite petroleum resources. Plant oils are promising renewable resources to produce environmentally friendly polymer applications. Soybean oil-based resins such as epoxidized soybean oil (ESO) and acrylated epoxidized soybean oil (AESO) have been well-known functionalized plant oils, but relatively low performances of their polymers and a competition with food production have been disadvantages. Thus, in this study, we designed new plant oil-based acrylates using non-food resources and achieved excellent properties of the acrylates for coatings and thermoset applications. Firstly, we developed coating materials with high mechanical, thermal and coating performances using acrylated epoxidized camelina oil (AECO) as a main acrylate monomer with various meth(acrylates) as reactive diluents Next, acrylated epoxidized cardanol modified fatty acids from camelina oil (AECFA) was successfully synthesized, and a phenolic structure with long aliphatic side chains with acrylic groups was obtained. The novel structure of AECFA provided rigidity into its polymer maintained with flexibility, and AECFA coating material showed better performances in terms of all properties such as mechanical, thermal, viscoelastic, and coating performances, as compared to commercial AESO resin. Finally, acrylated epoxidized allyl 10-undecenoate (AEAU) was developed from 10-undecenoic acid, castor oil derivative. The single fatty ester structure with di-functional acrylates of AEAU had very lower viscosity and showed better thermoset performances than those of triglyceride-based acrylates such as AESO and AECO. Thus, AEAU had a potential to an alternative to AESO for thermoset applications.

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Castro, Gutierrez Natalia. "Incorporation and release of organic volatile compounds in a bio-based matrix by twin-screw extrusion." Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/16006/1/Castro_Natalia.pdf.

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Nowadays, scientific and political communities are focused on ways to better preserve and manage the natural resources of our planet. In order to reduce consumption of fossil resources, and to develop more environmentally friendly industrial processes, the industry of flavors and fragrances became interested in developing new bio-based encapsulating materials. In the present work, maltodextrins have been chosen as main component of the matrix, and pea protein isolate and a modified starch were selected as compatibilizing additives. The incorporation of volatile odorant compounds and the elaboration of the new bio-based delivery systems were performed, all in one single step, by low temperature twin-screw extrusion. The physicochemical, thermal and morphological properties of these matrices were studied, as well as the encapsulation efficiency and the release profile of the active compounds. These investigations have led to a better understanding of the impact of the formulations and of the incorporation of the active compound on the process parameters. The interactions between the wall and the encapsulated materials were also analyzed. The characteristics of the new bio-based delivery systems and the established extrusion process conditions were found to be very promising to be employed in the field of perfumery.

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Tran, Thi Nguyet. "Bio-based elastomeric composites for antibacterial and antifouling applications : methodology for the synthesis and grafting of functionalized oligomers issued from natural rubber." Thesis, Le Mans, 2018. http://www.theses.fr/2018LEMA1024/document.

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Ce manuscrit présente la synthèse de nouveaux matériaux élastomères dérivés du caoutchouc naturel et de monomères organiques possédant des propriétés antifouling et/ou antibactériennes, liés de manière covalente au réseau polymère. Des monomères acrylates originaux comportant un groupement bioactif (un groupe guanidinium ou des dérivés de l'acide Zostérique) ont été synthétisés et co-polymérisés avec des oligomères acrylates téléchéliques. Aucun relargage significatif des monomères bioactifs n’'a eu lieu après immersion dans l'eau. Les films auto-portés synthétisés uniquement à partir des oligoisoprènes de type acrylate ont montré une faible activité antibactérienne qui a pu être drastiquement améliorée en intégrant aux films des monomères bioactifs. Les revêtements se sont montrés actifs contre plusieurs souches de bactéries pathogènes, parmi lesquelles P.aeruginosa, S.aureus, Bacillus subtilis et S.epidermidis. Afin de greffer de manière covalente des brosses d'oligoisoprène sur des surfaces, de nouveaux oligoisoprènes bifonctionnels comportant un groupe terminal alkoxy-silane ont été préparés puis couplés avec des matériaux à base de silicium. Une autre approche a également été étudiée, consistant à pré-fonctionnaliser la surface avec des groupements amino puis à partir de ces fonctions à greffer des oligomères ayant des extrémités carbonylés. La post-polymérisation à partir des extrémités de chaîne libres à la surface a donné un revêtement épais d’'oligoisoprène offrant une forte résistance à l'immersion dans des solvants (eau, THF). De cette manière, nous avons pu accéder à des couches moléculaires denses et liées, à des films minces et à des revêtements épais This manuscript presents the synthesis of new elastomeric materials based on natural rubber derived building blocks and organic monomers having antifouling and/or antibacterial properties, covalently bound to the polymer network. Original acrylate monomers bearing an organic bioactive moiety (a Guanidinium group or Zosteric acid derivates) were synthesized and co-polymerized with telechelic acrylate oligomers from polyisoprene. No significant leaching of the bioactive monomers occurred and the material resisted to long water immersions. Freestanding films prepared from acrylate oligoisoprenes also showed a weak antibiofouling activity which was drastically increased by integrating the guanidinium and the Zosteric acid monomers. The coatings were active against several strains of pathogenic bacteria among which Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Staphylococcus epidermidis. In order to covalently graft oligoisoprenes to surfaces, new bifunctional oligoisoprenes bearing an alkoxy-silane end moiety were designed and coupled with silicon-containing materials. An alternative approach was followed by prefunctionalizing the surface with amino groups and by covalently grafting oligomers with carbonyl chain-ends. Post-polymerization from the surface free chain-ends resulted in a thick oligoisoprene coating with strong resistance to solvent immersion (water, THF). In this way, we were able to build dense and tethered molecular layers, thin films and thick coatings

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Jaillet, Fanny. "Synthèse, formulation et caractérisation de matrices vinylester biosourcées pour l’élaboration de matériaux composites par pultrusion." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2014. http://www.theses.fr/2014ENCM0012/document.

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Les travaux présentés concernent le développement d'un matériau composite (matrice polymère + fibre) pour l'élaboration de profilés de fenêtre mis en œuvre par un procédé de pultrusion. Dans le cadre de ces travaux, plusieurs polymères vinylester biosourcés ont été développés en tant que matrice de ce matériau composite. Une résine vinylester est réalisée en deux étapes : tout d'abord la synthèse du prépolymère vinylester, correspondant à un monomère (méth)acrylé porteur de fonctions ester et qui possède des doubles liaisons polymérisable à ses extrémités. Puis, la formulation du matériau vinylester est effectuée par le mélange du prépolymère vinylester avec un monomère copolymérisable, appelé diluant réactif. Enfin, le matériau est réticulé par polymérisation radicalaire, à l'aide d'un amorceur radicalaire.Dans un premier temps, une étude modèle a été réalisée : de la synthèse du prépolymère vinylester à partir d'une molécule modèle (DGEBA) à la formulation d'un matériau vinylester par polymérisation radicalaire. Plusieurs bioressources ont ensuite été étudiées afin de remplacer le DGEBA qui est issu du bisphénol A, composé CMR, groupe 2. La stratégie a été tout d'abord d'étudier des bioressources commercialisées, tels que les huiles végétales et le cardanol qui est un sous-produit de l'industrie de la noix de cajou. Puis un produit non biosourcé, mais non classé, du nom de TACTIX a été étudié également. Et enfin des bioressources non commercialisées actuellement, tels que l'isosorbide qui est un dérivé du sucre et le phloroglucinol, qui est extrait d'écorce d'arbres ont également été étudié pour la synthèse de prépolymère VE et de matériaux VE. Le diluant réactif le plus utilisé actuellement est le styrène, qui est un composé très volatile et classé nocif. Plusieurs diluants réactifs ont donc été testés avec les prépolymères VE synthétisés afin de remplacer le styrène par des composés peu volatiles et non nocifs. Enfin, trois matériaux composite renforcés par des fibres de lin, ont été fabriqués par mini-pultrusion, à partir des systèmes étudiés (prépolymère VE synthétisé et diluant réactif) The study presented concern the development of composite material (polymer matrix + fibres) in order to produce windows profiles by a pultrusion process. In the context of this work, several biobased vinylester polymers have been developed as matrix of the composite material. A vinylester resin is formed in two steps: firstly the synthesis of vinylester prepolymer, corresponding to a (meth)acrylated monomer carrying an ester function and having polymerizable double bonds at its ends. Next, the formulation of vinylester material is performed by mixing the vinylester prepolymer with a copolymerizable monomer, called reactive diluent. Finally, the material is crosslinked by radical polymerization, using a radical initiator.First, a model study was conducted: in the synthesis of vinylester prepolymer from a template molecule (DGEBA) to the formulation of a vinylester material by radical polymerization. Severals bioresources were then studied in order to replace the DGEBA which is from bisphenol A, compound CMR, group 2. The strategy was first to study marketed bioresources, such as vegetable oils and cardanol which is a by-product of the cashew nut shell industry. Next, a non-biobased but not listed compound, of the name of TACTIX has also been studied. Finally, bioresources not currently marketed, such as isosorbide which is a sugar derivative and phloroglucinol, which is extracted of bark of trees have also been studied for the synthesis of VE prepolymers and VE materials. The reactive diluent the most currently used is styrene, which is a very volatile and harmful compound. Several reactive diluents were tested with the VE prepolymers synthesized in order to replace the styrene by compounds with low volatility and less harmful. Finally, three composites materials reinforced with flax fibres, were made by mini-pultrusion, from the systems studied (VE prepolymer synthesized and reactive diluent)

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BARBIERI, VIRGINIA. "Scarti cerealicoli: una risorsa rinnovabile e sostenibile per il settore edilizio." Doctoral thesis, Università degli studi di Modena e Reggio Emilia, 2020. http://hdl.handle.net/11380/1200735.

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Il grano è il più comune cereale impiegato in tutto il mondo. In Unione Europea, la quantità di scarto ottenuto dalla sua lavorazione è stimata a circa 10 milioni di tonnellate nel 2020. Attualmente non esiste una precisa strategia che preveda il recupero di questo sottoprodotto, il cui smaltimento, spesso incontrollato, provoca forti problemi ambientali. Recentemente, numerosi progetti finanziati dalla UE hanno evidenziato le possibilità di impiegare scarti agricoli nel settore edilizio, senza tuttavia prendere in considerazione uno dei principali sottoprodotti dalla lavorazione del grano: la lolla. Sebbene i materiali attualmente impiegati per l'isolamento termico dell'involucro edilizio abbiano prestazioni eccellenti, essi sono sintetici (polistirene estruso, polistirene espanso, schiuma di poliuretano, ecc.). Al contrario, i cosiddetti biocompositi sono eco-sostenibili. Tra questi, il più comune sul mercato è il calce-canapulo, ottenuto dalla combinazione della parte legnosa dello stelo di canapa e un legante a base di calce idrata e/o idraulica. Tale materiale ha buone proprietà di isolamento termico (0,05-0,12 W/(m*K)), eccellenti valori di Moisture Buffer e proprietà acustiche. Un'alternativa, ai leganti a base di calce calcica, sono i cementi magnesiaci. Il presente lavoro è finalizzato all'impiego della lolla di grano per lo sviluppo di un materiale isolante in alternativa al calce-canapulo. In tale contesto, sono state combinate le esigenze di due settori produttivi trasformando un materiale di scarto agro-industraiale in risorsa per l’edilizia. I risultati delle caratterizzazioni iniziali degli scarti di grano hanno mostrato valori di conducibilità termica (0,05 W / (mK)) e Moisture Buffer Value (2,06 g / (m2.% RH )) paragonabili al canapulo. Dunque, tale scarto è stato considerato una valida alternativa come riempitivo leggero per realizzare biocompositi. In successive indagini, il biocomposito a base di lolla e calce è stato preparato e confrontato con il canapulo-calce. Nonostante la maggiore densità apparente del primo, la porosità totale (circa 80%) e la conducibilità termica (0,09 W /(m.K)) sono simili per entrambi i biocompositi. Prestazioni meccaniche leggermente inferiori sono state riscontrate per il composito contente la lolla (~ 0,20 MPa) rispetto all’equivalente con canapulo (0,24 MPa), ciò è stato attribuito alla minore adesione riempitivo-legante. Al fine di ottenere un materiale con migliori prestazioni meccaniche, il lavoro successivo è stato dedicato allo studio di un legante alternativo caratterizzato da una migliore compatibilità con il nuovo riempitivo vegetale. In particolare, è stato studiato un cemento magnesiaco, la cui presa e indurimento si basa sull'idratazione del MgO reattivo in presenza di MgSO4 e una farina vegetale. Il risultato è una microstruttura porosa complessa composta da fasi di magnesio ossisolfato a forma di ago e idrossido di magnesio. I biocompositi lolla-matrice magnesiaca e canapulo-matrice magnesiaca sono stati preparati e confrontati con i corrispondenti biocompositi a base di calce precedentemente studiati. Migliori prestazioni meccaniche sono state riscontrate per i compositi preparati con legante magnesiaco. Nel particolare, sono state osservate le più alte resistenze a compressione per i compositi preparati con la lolla. Indagini microstrutturali hanno dimostrato che sia la minore porosità che la maggiore adesione dello riempitivo con la fase legante sono responsabili delle migliori prestazioni meccaniche. Concludendo, questa ricerca di dottorato ha evidenziato la possibilità di utilizzare scarti di lavorazione del grano, senza pretrattamenti energivori, per lo sviluppo di materiali destinati all’isolamento termico in alternativa ai materiali isolanti tradizionali più inquinanti. Wheat is the most common type of cereal used worldwide and the production of wheat husk waste from the refinement process is estimated to ca. 10 million tons in 2020 only in the EU. Since now, no well-defined recycling strategy exists and natural decomposition with the consequent production of polluting greenhouse gases is often the final destination of these materials. Recycling of agricultural by-products, in particular in the building sector, have recently been in focus through many EU-funded project. However, wheat husk has not yet been investigated. Although current thermal insulation materials have excellent performances, they are generally based on petroleum-derived raw materials (e.g. extruded polystyrene, expanded polystyrene, polyurethane foam, etc.). So-called bio based building material are more environmental-friendly alternatives, the most common one available on the market being lime hemp concrete. This material contains hemp hurds as filler and hydrated and/or hydraulic lime as binder. The material has good thermal insulation properties (0.05-0.12 W/m*K) and excellent moisture buffering and acoustic properties. An alternative to lime-based binders, having the same or even better green value, are magnesia-based ones. The present work was aimed to the design of wheat husk insulating material as potential alternative to hemp lime concrete. The idea was to combine the necessity of finding valid recycling alternative for wheat husk with the need of the building sector for environmental-friendly insulation materials. The results from initial physical characterizations of wheat husk showed a low dry thermal conductivity (ca. 0.05 W/(m.K)), comparable to hemp hurd, as well as good hygric regulation performances (MBV equal to 2.06 g/(m2.%RH)). Hence, the material was considered a viable alternative as filler in biocomposites. In subsequent investigations, lime wheat husk concrete was prepared and compared to a lime hemp concrete. Despite the higher dry apparent density of the former, the total porosity (around 80%) and dry thermal conductivity (ca. 0.09 W/(m.K)) were similar for both types of concrete. The somewhat lower mechanical performance of lime wheat concrete (~0.20 MPa) with respect to lime hemp concrete (0.24 MPa), although in line with those expected for infilling walls without load bearing requirements, was found to be due to lower adherence of wheat husk to the lime-based binder. In order to obtain a material with improved mechanical performance, subsequent work was dedicated to investigated an alternative binder with better compatibility with the novel vegetal filler. In particular, a magnesia-based cementitious materials was investigated. Setting and hardening of the investigated system relied on hydration of reactive MgO in the presence of MgSO4 and a vegetal flour leading to a complex porous microstructure composed of needle-shaped magnesium oxy sulfate cement phases as well as magnesium hydroxide with carbon uptake potential. Wheat husk magnesia concrete and hemp hurd magnesia concrete were prepared and compared to the corresponding lime-based materials previously investigated. Mechanically stronger composites were obtained with magnesia-based binder. In addition, the best mechanical performance was observed for composites containing wheat husk as filler. Microstructural investigations showed that both lower porosity and stronger adhesion of wheat husk aggregate with the binder phase are responsible for the improved mechanical performance. Concluding, the results obtained during this PhD research showed that direct utilization, i.e. without any energy-consuming pre-treatments, of wheat husk for the production of bio based building materials intended for thermal insulation purposes is a viable recycling option and a valid alternative/substitute for less environmental-friendly traditional insulation materials.

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Roumeas, Laurent. "Étude des voies de dépolymérisation chimique des tanins condensés : vers une production industrielle de composés phénoliques biosourcés." Thesis, Montpellier 1, 2013. http://www.theses.fr/2013MON13522.

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La substitution des composés carbonés d'origine fossile par des matières premières renouvelables représente un enjeu majeur et stratégique pour l'environnement, l'économie, et la santé publique. Nous nous sommes particulièrement intéressés au cas des dérivés du phénol, largement utilisés dans le domaine des matériaux synthétiques (résines, plastiques). Des travaux antérieurs ont démontré le potentiel des monomères de flavanols, sous-unités constitutives des chaines polymériques des tanins condensés comme substituts aux phénols issus de la pétrochimie, tels que le bisphénol A, l'objectif du présent travail a été de contribuer au développement d'une voie industrielle d'accès à de tels composés par dépolymérisation des tanins condensés (proanthocyanidines), une ressource végétale abondante mais actuellement peu exploitée pour ce type d'applications. Cette dépolymérisation peut être obtenue par rupture de la liaison interflavanique en milieu acide et piégeage des carbocations formés par un réactif nucléophile. Différentes stratégies et conditions ont été étudiées pour mieux comprendre le rôle de l'acide, du nucléophile, du solvant et l'impact de la température sur la réaction de dépolymérisation. Les stratégies sélectionnées, menées sur un dimère B2 pur servant de modèle et sur un extrait industriel de tanins de pépins de raisins blancs issus de marcs à l'échelle du gramme, ont été comparées en termes de rendement, de cinétique, de stabilité des produits, et de facilité de mise en œuvre et de traitement dans la perspective d'une production à plus grande échelle respectant au mieux les objectifs du développement durable et les contraintes de l'industrialisation The substitution of fossil carbon by renewable raw materials is a major strategic challenge for the environment, economy and public health. Our thesis focuses on the utilisation of phenol derivatives, which are widely used in the field of synthetic materials (resins, plastics). Previous studies have demonstrated the potential of plant flavanol monomers as substitutes for petrochemical phenols such as bisphenol A. The objective of this work was to contribute to the development of an industrial access to such compounds by depolymerization of condensed tannins (proanthocyanidins), an abundant plant resource currently untapped for such applications. Depolymerization can be performed by breaking the interflavan bonds in acidic medium and scavenging the released carbocations by a nucleophilic reagent. Various strategies and conditions were studied and compared to better understand the role of the acid, the nucleophile and the solvent and temperature in the depolymerisation reaction. The selected strategies, applied on a pure B2 dimer used as a model and an industrial seed tannins extract from white grape pomace at the gram scale, were compared in terms of performance, kinetics, product stability, ease of implementation and work-up in the context of a larger scale production complying with the objectives of sustainable development and the constraints of industrialization

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Rosén, Therese. "RosaNovum : En studie om att skapa materialacceptans genom en Material driven designprocess för en cirkulär ekonomi." Thesis, Malmö universitet, Institutionen för konst, kultur och kommunikation (K3), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-44451.

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Cirkulär ekonomi bygger på principerna om att designa bort avfall, där avfall ses som en råvaruresurs. För att övergå till ett fossilfritt samhälle kommer material från förnyelsebara råvaror att behövas. Biobaserade material har oftast inte samma tekniska egenskaper och estetiska uttryck som befintliga material, biobaserade DIY-material utvecklade från okonventionell råvaruresurs kan väcka starka positiva och negativa reaktioner hos användarna. Studien har undersökt hur man i en Material driven designprocess genom form och kultur kan skapa acceptans för ett biobaserat DIY material från en okonventionell råvaruresurs. Studiens huvudsyfte har varit att bidra med ny kunskap för att underlätta för designers i en Material Driven Designprocess, att identifiera användningsområden och produktform som kan stärka materialacceptans hos användare. Fördjupningsområden i studien är teorier för Hållbar utveckling, Cirkulär ekonomi, Bioekonomi, Material Driven Design for Sustainability och Culture Sensitive Design. Huvudmetoden i studien har varit Material Driven design, vilket innefattas av ett flertal designmetoder. Studien visar på att den kulturella koppling mellan användarna och råvarans ursprung har i denna studie haft en signifikant betydelse för material acceptansen genom att skapa mening för användaren och att materialet primärt behöver applicerat i en produkt på ett sådant sätt att användaren känner tillit till dess prestanda. Resultatet presenteras i form av ett förslag på en användare studie och en produktprototyp. A circular economy is based on the principles of designing away waste, where waste is seen as a raw material resource. To move to a fossil-free society, materials from renewable raw materials will be needed. Bio-based materials usually do not have the same technical characteristics and aesthetic expressions as existing materials, bio-based DIY materials developed from unconventional raw material resources can provoke strong positive and negative reactions among users. This study has investigated how a Material-driven design process through form and culture can create acceptance for a bio-based DIY material from an unconventional raw material resource. The study's main purpose has been to contribute with new knowledge to make it easier for designers in a Material Driven Design process to identify uses and product forms that can strengthen material acceptance among users. In-depth areas in the study are theories for Sustainable Development, Circular Economy, Bioeconomy, Material Driven Design for Sustainability and Culture Sensitive Design. The main method of the study has been Material Driven Design, which is covered by several design methods. The study shows that the cultural link between the users and the origin of the raw material has had a significant impact on material acceptance by creating meaning for the user and that the material primarily needs to be applied in a product in such a way that the user has confidence in its performance. The results are presented in the form of a proposal for a user study and a product concept.

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McMaster, Michael S. "Optoelectronic Applications For Bio-Based Materials." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case155257775382127.

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Hu, Chaohe. "Versatile biobased particles of acrylate vegetable oils : Synthesis and applications." Thesis, université Paris-Saclay, 2022. http://www.theses.fr/2022UPAST081.

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Depuis ses débuts, au début des années 1920, l'industrie des polymères dépend fortement des ressources en combustibles fossiles. Environ 4 à 8 % du pétrole, du gaz et de leurs dérivés sont aujourd'hui transformés en matériaux polymères. La plupart d'entre eux sont non recyclables et non dégradables, ce qui entraîne de graves problèmes environnementaux, préjudiciables à la faune et à l'homme. Dans ce contexte, il est nécessaire de développer des produits polymères alternatifs qui, à partir de matières premières renouvelables, présenteront le même niveau de complexité que les produits actuels issus de l'industrie pétrolière.Parmi les différentes matières premières biosourcées utilisées pour fabriquer des matériaux polymères, les huiles végétales sont prometteuses pour leur faible coût et leur dégradabilité intrinsèque, mais aussi parce que leur production est déjà optimisée pour l'industrie alimentaire. L'huile de soja époxydée acrylée (AESO) est un exemple des dérivés d'huiles végétales qui sont utilisés comme additifs plastifiants pour la formulation du PVC. Seule, l'AESO peut être facilement et rapidement polymérisée pour donner un polymère thermodurci. Cependant, en raison de sa viscosité intrinsèque élevée, la plupart des recherches sur les polymères à base d'AESO se sont concentrées jusqu'à présent sur les propriétés de masse, de revêtement ou de film de ce matériau, laissant dans l'ombre la possibilité de fabriquer des matériaux à haute valeur ajoutée.Ce travail se concentre sur la fabrication et l'application des microparticules d'AESO. Nous présentons d'abord une approche simple à travers un mélangeur vortex pour préparer les particules AESO polydispersées basées sur la photopolymérisation en émulsion. Les microparticules AESO synthétisées présentent une bonne dégradabilité dans des conditions chimiques et enzymatiques. Ensuite, nous développons un dispositif microfluidique " one pot " avec une structure de focalisation du flux pour l'émulsification et une zone serpentine pour la réticulation induite par les UV, qui peut être utilisé pour produire en continu des particules AESO monodispersées avec une taille réglable. Nous démontrons également la méthode basée sur les puces microfluidiques modifiées pour préparer les particules non sphériques, où une puce avec une jonction de focalisation d'écoulement en forme de Y est utilisée pour préparer les particules AESO en forme de croissant et une autre puce avec une double jonction de focalisation d'écoulement est utilisée pour synthétiser les particules AESO structurées en coquille de trou. De plus, des microcapsules d'AESO sont fabriquées par la puce personnalisée et elles sont disponibles pour encapsuler des solutions ou des substances aqueuses. Enfin, nous montrons la capacité des microparticules AESO à transporter les molécules organiques dans leurs réseaux réticulés et utilisons des méthodes similaires pour charger les médicaments (curcumine et ibuprofène). Le comportement de libération des médicaments dans le fluide corporel simulé peut être observé, ce qui peut constituer un support prometteur pour d'autres applications pharmaceutiques Since its beginning, in the early 1920's, polymeric industry relies heavily on fossil fuel resources. Approximately 4%-8% oil, gas and their derivatives are nowadays transformed into polymeric materials. Most of them are non-recyclable and non-degradable, hence leading to serious environmental issues, detrimental to wildlife and humans. In this context, there is a need for the development of alternative polymeric products, which, starting from renewable commodities, will share the same level of complexity than current ones derived from oil industry.Among the various bio-sourced raw products used to make polymeric materials, vegetable oils are promising for their low cost and intrinsic degradability, but also because their production is already optimized for the food industry. Acrylated epoxidized soybean oil (AESO) is one example of the vegetable oil derivatives that are used as e.g. plastifying additives for the formulation of PVC. Alone, AESO can be readily and rapidly polymerized to give a thermoset polymer. However, as a consequence of its high intrinsic viscosity, most of the research on AESO-based polymer so far is only focused on the bulk, coating or film properties of this material, leaving the possibility to fabricate high added value materials a blind spot.Herein, this work focuses on the fabrication and application of the AESO microparticles. We first present a simple approach through a vortex mixer to prepare the polydispersed AESO particles based on the emulsion photopolymerization. The synthesized AESO microparticles present a good degradability in the chemical and enzymatic conditions. Then, we develop a “one pot” microfluidic device with a flow-focusing structure for emulsification and the serpentine zone for UV-induced reticulation, which can be used to continuously product the monodispersed AESO particles with a tunable size. We also demonstrate the method base on the modified microfluidic chips to prepare the non-spherical particles, where a chip with Y-shape flow-focusing junction is used to prepare the crescent-shaped AESO particles and another chip with a double flow-focusing junction is utilized to synthesize the hole-shell structured AESO particles. In addition, AESO microcapsules are fabricated by the customized chip, and they are available to encapsulate the aqueous solutions or substances. Finally, we show the ability of AESO microparticles to carry the organic molecules into their crosslinked networks and use the similar methods to load the drugs (curcumin and ibuprofen). The release behavior of drugs in simulated body fluid can be observed, which may be act as a promising drug carrier for further pharmacy applications

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Chard, Jonathan Michael. "The development of bio-based composite materials." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616320.

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Owing to the increasing global population and more widespread industrialisation (particularIy with respect to the developing world's aspirations to equality of standard of living), the extraction and use of materials is expanding. This ever-increasing demand for materials has meant that certain resources are under pressure. Polymer matrix composites, which are normally derived from petrochemicals with synthetic fibres requiring high amounts of energy during manufacture, are increasingly used for both structural and non-structural applications. The development of composites using bio-derived fibres or resins (or both) is an important area of research. This study considers the mechanical propelties of various bio-derived fibres, laminated with a range of standard (commercially available) and modified (tailored or with bio-derived content) thelIDosetting resins, in comparison with synthetic equivalents. The sta11ing point for the current work was to manufacture composites using commonly available natural fibres (hemp, in both chopped strand mat and unidirectional form) with commercial resin systems, primarily to investigate a potential marketing opportunity. This work has shown that it is possible to manufacture such composites, but that their mechanical properties are not particularly useful: in some cases they are in fact worse than the bulk resin. In part this is due to the compatibility of the resin with the fibres. This has been addressed to some extent by the optimisation of the composite with a coupling agent to the formulation. Of more interest however has been the identification of a processed-cellulose fibre, available in a continuous form. Composites made from this have interesting prope11ies and, due to the comparatively low density of the fibres, the specific mechanical propelties of the composites are comparable with those of glass based systems. In addition, this study has also conducted an environmental LCA of thermosetting resin manufacture; the conclusions of this have informed the corporate sponsor (Scott BadeI') of strategies for reducing the environmental impact of resin manufacture.

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Zhang, Rui Liang, and Lukas Rask. "A cost estimation of an industrial scale production of nanocellulose filaments utilizing PBCM and TRL : A case study at RISE Research Institutes of Sweden AB." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264079.

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Producing the strongest bio-based material called nanocellulose, in the form of filaments, has shown to be technically feasible at lab-scale, but the production costs remain unknown. The research has focused on technical feasibility and less on costs, which is a common phenomenon when developing new technologies. Constructing a Process-Based Cost Model (PBCM) can link the technical aspects of a technology to its costs of production. However, the accuracy of such a model might be dependent on the data availability of the technology. In this study, the technology of producing nanocellulose filaments has been evaluated along the scale of Technology Readiness Level (TRL) to understand the maturity of the technology and a PBCM has been constructed to show the economic prerequisites for the production of nanocellulose filaments. The main results indicate that at TRL 4, with parts of TRL 5 fulfilled, parameters such as Capital Expenditures cannot be allocated to unit production cost, only Operational Expenditures. Therefore, the relevant cost elements become material and energy as these constitute the currently available data. The PBCM can thus be used to estimate the production costs of different scenarios while highlighting the areas of future research. In the empirical context of nanocellulose filament production, utilizing deionized water in the production is a more promising option compared to utilizing solvents as the cost of recovering the solvent becomes high. Furthermore, using deionized water also becomes more promising due to the fact that other scenarios have not yet been evaluated experimentally. However, as the technology matures and more data becomes available, the model accuracy will increase as more parameters can be included in the model and the basis increases for decisionmaking regarding techno-economic concerns of the technology. Produktionen av världens starkaste biobaserade material, nanocellulosa i filamentform, har visat sig vara tekniskt möjligt på labbskala, men produktionskostnaderna är idag okända. Forskning som fokuserar mer på den tekniska genomförbarheten och mindre på produktionskostnader är ett vanligt förekommande fenomen i utveckling av ny teknologi. Genom att konstruera en processbaserad kostnadsmodell (PBCM) kan en teknologis tekniska aspekt länkas till dess produktionskostnader. Dock påverkas en sådan modells noggrannhet av datatillgängligheten för teknologin. I denna studie har teknologin för produktionen av nanocellulosa filament utvärderats längs med Technology Readiness Level (TRL) skalan för att förstå teknologins mognadsgrad. Därefter har en PBCM konstruerats för att visa de ekonomiska förutsättningarna för en produktion av nanocellulosafilamenten på industriell skala. Huvudresultaten indikerar att på TRL 4, med delar av TRL 5 uppfyllda, kan somliga parametrar såsom investeringskostnader inte allokeras till enhetsproduktionskostnaden, utan bara löpande kostnader. De relevanta kostnadselementen blir därför material och energi då dessa utgör den aktuellt tillgängliga datan. PBCM kan därför användas för att beräkna produktionskostnader av olika scenarion och lyfta fram områden för framtida forskning. I den empiriska kontexten av produktionen av nanocellulosafilament är användningen av avjoniserat vatten ett mer lovande alternativ jämfört med användningen av lösningsmedel då kostnaden för återvinningen av lösningsmedlet blir högt. Dessutom är användningen av avjoniserat vatten mer lovande eftersom övriga scenarion inte har testats experimentellt än. Allteftersom teknologin mognar och mer data blir tillgänglig, så kommer modellens noggrannhet öka då fler parametrar kan inkluderas i modellen och därmed kan underlaget öka för beslutsfattning gällande teknoekonomiska frågor om teknologin.

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Yang, Yunxian. "Bio-based flame retardant for sustainable building materials." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/668530.

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As new promising alternatives, novel bio-based materials are already developed to apply in construction sectors due to biodegradability, low toxicity, sustainability, renewability, and acceptable general properties. However, their flammability and need to guarantee a low fire risk in the constructions is also an essential factor to restrict their further application. This thesis focused on investigation of bio-based material with good flame-retardant performance and corresponding flame-retardant mechanism. The detailed investigation was developed by following stages: synthesis of bio-based flame retardant and its application in PLA; effect of bio-based flame retardant on the fire resistance and other properties of natural fiber reinforced PLA. Finally, the smouldering and combustion performances of the bio-based thermal insulation material made from natural fiber were studied as well. 1) On basis of bio-based concept, PA and THAM were selected as raw material to synthesize a novel flame retardant and the chemical structure was confirmed via some characterizations. Afterwards, this synthetic product PA-THAM was employed as an efficient flame retardant to PLA by melt mixing. This binary system showed an improvement in flame retardancy, which was achieved by a combination of heat transfer effect, slight dilution and barrier action. For example, only 3 wt% loading of PA-THAM imparted PLA-based biocomposite LOI value of 25.8% and UL 94 V-0 level, as well as a significant self-extinguishing ability was observed. Besides, the molten viscosity of biocomposite also demonstrated more reduction compared with neat PLA due to the lubrication of PA-THAM, while there was little change in the mechanical properties. 2) PA-THAM and corn pith cellulose (OCC) were combined via in-situ modification and used to prepare a PLA-based biocomposite. After OCC was modified by PA-THAM successfully, which was proved by SEM/ EDS, FTIR, and TGA, the effect of PA-THAM on thermal stability and fire behaviors of PLA-based composite were also investigated accordingly. 5 phr addition of PA-THAM enabled this natural fiber reinforced polymer biocomposite (NPC) to illustrate a 50 °C higher temperature at maximum degradation rate than control sample without additive, and an improvement was also obtained in flame retardant properties with an increase of LOI value, a reduction of PHRR, and more char residue. The predominant flame-retardant mechanism focused on the synergistic effect of PA-THAM and OCC that occurred in condensed phase. Besides, the same level introduction of PA-THAM improved the interfacial affinity between PLA and OCC that maintained good mechanical properties as well. 3) A bio-based thermal insulation material was made from corn pith cellulose, alginate, and bio-efficient flame retardants. After introducing these bio-based additives, the smouldering and flaming combustion behaviors were improved significantly. Compared with the reference sample, thermal insulation particleboard with 8 wt% loading of a mixture of PA-THAM and a sodium borate salt (DOT) increased the initial temperature of smoldering ignition by 70 ºC, and meanwhile, the value of PHRR in flaming combustion decreased by 25.5%. Furthermore, the thermal conductivity was hardly affected, while the temperature at which the maximum thermal degradation occured increased. The correlative flame retardant mechanism was attributed to a synergistic effect from both flame retardants, which promoted a formation of more stable charring layer at initial stage. Los materiales de base biológica ofrecen una alternativa prometedora para aplicaciones en el sector de la construcción, debido a que se trata de materiales biodegradables, renovables y de baja toxicidad. Sin embargo, su capacidad de inflamar y la necesidad de mantener un bajo riesgo frente a incendios en los edificios es un factor esencial para restringir su posterior aplicación. Esta tesis se ha centrado en el desarrollo de materiales de base biológica con buen comportamiento frente al fuego y la investigación de los mecanismos de los retardantes de llama involucrados. La investigación se desarrolló en tres etapas que se detallan a continuación. 1) Partiendo del concepto de base biológica, se seleccionaron PA y THAM como materias primas para sintetizar un nuevo retardante de llama y la estructura química se confirmó mediante la caracterización del compuesto resultante. Posteriormente, este producto sintético PA-THAM se empleó como un retardante de llama eficiente para PLA mediante mezcla fundida. Este sistema binario mostró una mejora en la resistencia al fuego, que se logró mediante una combinación de los efectos de transferencia de calor, ligera dilución y acción barrera. Por ejemplo, con sólo un 3% en peso de carga de PA-THAM se logró un valor de LOI de 25,8% del compuesto de PLA y un nivel UL 94 V-0, así como una capacidad de autoextinción significativa. Además, la viscosidad fundida del biocompuesto también se redujo en relación a la del PLA puro debido a la lubricación ejercida por el PA-THAM. Por otro lado, la adición del retardante ocasionó pocos cambios en las propiedades mecánicas. 2) El retardante basado en PA-THAM y la fracción fina obtenida triturando la médula de maíz (OCC) se combinaron mediante modificación in situ y se usaron para preparar un biocompuesto basado en PLA. La médula de maíz fue modificada con éxito con el PA-THAM, la cual cosa se demostró por SEM / EDS, FTIR y TGA, el efecto de PA-THAM sobre la estabilidad térmica y el comportamiento al fuego del material compuesto a base de PLA también fueron investigados. La adición de 5 phr de PA-THAM permitió a este biocompuesto reforzado con fibras naturales (NPC) alcanzar una temperatura 50 °C más alta en el punto de degradación máximo comparado con la muestra de control sin aditivo. También se obtuvo una mejora en el comportamiento al fuego con un aumento del valor de LOI, una reducción del pico máximo del ritmo de liberación de calor (PHRR), y una mayor formación de residuo carbonizado. El mecanismo ignífugo predominante se centró en el efecto sinérgico del PA-THAM y la OCC que ocurrió en la fase condensada. Además, el mismo nivel de introducción de PA-THAM mejoró la afinidad interfacial entre PLA y OCC que también mantuvo buenas propiedades mecánicas. 3) Se prepararon muestras de un material de aislamiento térmico de base biológica a partir de médula de maíz, alginato y retardantes de llama de origen biológico. La adición del retardante de llama de base biológica logró mejorar significativamente el comportamiento al fuego, y el fenómeno de combustión sin llama (smouldering). En comparación con la muestra de referencia, el panel aislante con una carga de 8% en peso de una mezcla de PA-THAM y una sal de borato de sodio (DOT) aumentó la temperatura inicial a la que se produce la combustión sin llama en 70 ºC y, permitió reducir el valor de PHRR en un 25.5%. Además, la conductividad térmica apenas se vio afectada, mientras que la temperatura a la que se produce el valor máximo de degradación térmica aumentó notablemente. El análisis del mecanismo de acción de los retardantes reveló la existencia de un efecto sinérgico de ambos retardantes de llama, que promovió la formación de una capa de carbonización más estable en la etapa inicial.

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Miranda, Michael Angelo. "Bio Based Active Barrier Materials and Package Development." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1483450387453053.

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Gea, Saharman. "Innovative bio-nanocomposites based on bacterial cellulose." Thesis, Queen Mary, University of London, 2011. http://qmro.qmul.ac.uk/xmlui/handle/123456789/2343.

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A variety natural materials that are environmentally friendly, renewable and low cost have been created. Bacterial cellulose (BC), which is produced by a harmless bacterium, Acetobacter xylinum, has been used as a reinforcement agent to form bionanocomposites. Apple and radish pulp which are themselves cellulosic, were blended with bacterial cellulose to produce a high quality nanopaper which can be used for special purposes. The resulting sheets are characterised in terms of their morphology as well as their mechanical and thermal properties. Another approach adopted was the combination of BC with bio-polymers such as poly (ε-caprolactone) and a commercially available starch based polymer, Mater-Bi. Freeze-dried BC, which was kept in its 3D shape, was used as a comparison. These innovative composite systems are non-petroleum based and are biodegradable. The morphology, structure, thermal properties and performance of the resulting bio-composites were investigated using scanning electron microscopy, Fourier Transform Infrared spectroscopy, Differential Scanning Calorimetry, Dynamic Mechanical Analysis, and by measuring the mechanical properties. Purification is a crucial step in removing impurities and another organic materials remaining in the BC. The BC gel which was purified in two steps, i.e. with 2.5 wt.% NaOH and then bleaching with 2.5 wt.% NaOCl respectively, showed a greater performance in its thermal and mechanical properties. In addition, it was shown that the cellulose I structure of BC is not converted to cellulose II. BC is an interesting material for in-vivo studies. However, to make it an interesting biological composite a suitable resin must be found. Poly (vinyl alcohol) (PVA) is a known water soluble polymer and is therefore a suitable candidate material. In this study BC was grown in PVA solution to produce an in-situ composite. The concluding work for this project is an in-vitro study of BC for scaffolds for tissue engineering. The BC network was seeded with bovine chondrocytes (bone cells) obtained from an 18 months old deer and cultured into the BC gel to establish the viability of this material for medical applications.

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Hu, Bo. "Bio-based composite sandwich panel for residential construction." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 5.24 Mb., 265 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3221055.

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Dovberg, Ludvig, and Löfgren Tobias. "LERGJORD : Stampad lerjord som ett innovationsmaterial i Skåne." Thesis, Malmö universitet, Institutionen för Urbana Studier (US), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-44670.

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Lergjord is a thesis that puts emphasis on the possibility of innovation by using local biobased material in the building industry of Skåne in Sweden. The thesis examines if rammed earth can be used in the implementation of LFM30 (Translated into English: Local Sustainable Goals in Malmö by 2030). By use of qualitative research methods, views on rammed earth as a building technique was explored by three stakeholders. This research has concluded if rammed earth is possible in Skåne as a conventional material in the future. We (Ludvig Dovberg and Tobias Löfgren) have examined the practical aspect of rammed earth on Urban Living Lab in the municipality of Lund by the use of local clay material from excavation for an expansion of a new railway between Malmö and Lund in collaboration with Trafikverket. This thesis concludes that rammed earth is feasible with clay from the excavation masses through project LERGJORD. Also, due to the vast quantity of it the resource might be useful for future rammed earth projects in Skåne. However, the building technique itself has some major drawbacks such as time-consumption and the knowledge gap is easily addressed. Although, there has been a development of a pre-fabrication concept of the building technique in Germany since the late 1990s, that could be a solution to the problem. The thesis also concludes that higher education and research is compulsory to establish a knowledge base for architects to work by. The case study showcased that a standardization of the material is needed to prevent vast material testing before being accepted for construction, like the Lehmbau-praxis in Germany. According to the material’s low impact in CO₂-emission and circularity this resourceful extraction could be of interest by the members of LFM30 to implement in the building industry of Skåne. Lergjord är ett arbete som undersöker möjligheten till innovation genom att utnyttja lokala biobaserade material i Skåne i Sverige. Arbetet undersöker om stampad jordbyggnad kan användas för att genomföra de Lokala Färdplansmålen som Malmö Stad sätter fram till år 2030 (förk. LFM30). Genom kvalitativa forskningsmetoder undersöktes stampad lerjord som byggnadsteknik hos tre intressenter. Studien har sammanfattat möjligheten om hur stampad lerjord i Skåne kan bli ett konventionellt byggmaterial i framtiden. Vi (Ludvig Dovberg och Tobias Löfgren) har utvärderat den praktiska aspekten i stampad lerjord på Urban Living Lab i Lund med användandet av lokal lerjord från utgrävningar av tillbyggnation för järnvägsspår mellan Malmö och Lund i samarbete med Trafikverket. Arbetet visar att stampjordstekniken är möjlig med utvunnen lera från schaktmassorna mellan Lund och Malmö med hänvisning till projekt LERGJORD. Med tanke på den stora kvantitet av lera som finns kan denna utvinning vara användbar för andra projekt i Skåne. Hursomhelst, byggtekniken besitter på utmaningar såsom tidskrav och kunskapsluckan är tämligen lätt att adressera. Trots det, har ett prefabriceringskoncept inom byggtekniken utvecklats sedan slutet på 1990-talet i Tyskland, som kan vara en lösning på problemet. Arbetet tyder också på att högre utbildning och forskning krävs för att etablera en kunskapsbas som arkitekter kan arbeta vidare på. Fallstudien visar på att en standardisering av materialet krävs för att undvika långa och omständliga materialtester innan godkännande för konstruktion, likt Lehmbau-lagstiftningen i Tyskland. Materialets låga klimatpåverkan och cirkularitet gör det relevant för LMF30’s medlemmar att se vidare på alternativet för implementering i den skånska byggindustrin.

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Niang, Ibrahim. "Contribution à la certification des bâtiments durables au Sénégal : cas d'étude des matériaux de construction biosourcés à base de Typha." Thesis, Reims, 2018. http://www.theses.fr/2018REIMS030.

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Ces travaux de thèse s'inscrivent dans le cadre du projet PNEEB/Typha (Programme National d’Efficacité Energétique des Bâtiments) pour la valorisation d’un roseau invasif, le Typha Australis, comme isolant thermique pour améliorer l’efficacité énergétique des bâtiments au Sénégal. Un agromatériau à base de terre argileuse et de granulats de Typha Australis est élaboré afin d’évaluer l’influence de la morphologie et de la quantité de fibres sur le comportement du matériau. Pour cela, deux modes de production de granulats sont choisis : Une découpe longitudinale et une découpe transversale. Les propriétés physiques sont étudiées (taux de porosité, densité apparente et absolue, microstructure) et la tenue mécanique est déterminée. L'absorption acoustique est également évaluée, de même que les propriétés hygrothermiques et le comportement au feu. Les résultats montrent que la morphologie du granulat de Typha affecte le comportement en flexion, cisaillement et l’absorption acoustique. Son impact sur le comportement de compression est moins prononcé. Une portion plus importante de fibres de Typha réduit la résistance mécanique. En revanche, les performances hygrothermiques sont accrues en raison de la porosité de ces granulats. La fraction transversale de Typha permet d’améliorer la résistance thermique et d’accroitre les phénomènes de transfert de la vapeur d'eau. Cette étude a également permis de montrer que ces matériaux sont d'excellents régulateurs d'humidité. Enfin, les tests au feu révèlent qu’il s’agit de combustibles ininflammables en raison de la présence d'argile. L’influence de la morphologie des granulats n’est pas relevée This work is a part of PNEEB/Typha project (National Program for Energy Efficiency of Buildings) for the valorisation of an invasive reed, the Typha Australis, as a thermal insulator to improve the energy efficiency of buildings in Senegal. An agromaterial based on clay soil and Typha Australis is elaborated in order to evaluate the influence of the amount and fibres morphology on the material behaviour. For this, two production mode of granulates are chosen: longitudinal and transversal cut. Physical properties are studied (porosity, apparent, and absolute density, microstructure) and mechanical strength is determined. Sound absorption is also evaluated, as well as hygrothermal properties, and fire behaviour. Results show that granulate morphology affects the mechanical shear and flexure behaviour, as well as the acoustic absorption. Its impact on the compression strength is less pronounced. A greater portion of Typha fibers reduces the mechanical strength. However, hygrothermal performances are increased due to the aggregates porosity. Typha transverse fraction improves thermal resistance and increase water vapor transfer. This study also shows that these materials are excellent moisture regulators. Finally, fire tests reveal that it can be classified as combustible but non-flammable due to the clay presence. The fibres shape does not have a great influence

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Merighi, Stefano <1992&gt. "Novel bio-based amine curing agents for epoxy resins: the way towards fully bio-based composite materials." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9341/1/PhD%20Thesis_Stefano%20Merighi.pdf.

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Epoxy resins are widely used in many applications, such as paints, adhesives and matrices for composites materials, since they present the possibility to be easily and conveniently tailored in order to display a unique combination of characteristics. In literature, various examples of bio-based epoxy resins produced from a wide range of renewable sources can be found. Nevertheless, the toxicity and safety of curing agents have not been deeply investigated and it was observed that all of them still present some environmental drawback. Therefore, the development of new environmentally friendly fully bio-based epoxy systems is of great importance for designing green and sustainable materials. In this context, the present project aims at further exploring the possibility of using bio-based compounds as curing agents for epoxy resin precursors. A preliminary evaluation of several amine-based compounds demonstrated the feasibility of using Adenine as epoxy resin hardener. In order to better understand the crosslinking mechanism, the reaction of Adenine with the mono-epoxy compound Glycidyl 2-methylphenyl ether (G2MPE), was study by 1H-NMR analysis. Then Adenine was investigated as hardener of Diglycidil ether of bisphenol A (DGEBA), which is the simplest epoxy resin based on bisphenol A, in order to determine the best hardener/resin stoichiometric ratio, and evaluate the crosslinking kinetics and conversion and the final mechanical properties of the cured resin. Then, Adenine was tested as hardener of commercial epoxy resins, in particular the infusion resin Elan-tron® EC 157 (Elantas), the impregnation resin EPON™ Resin 828 (Hexion) and the bio-based resin SUPER SAP® CLR (Entropyresins). Such systems were used for the production of composites materials reinforced with chopped recycled carbon fibers and natural fibers (flax and jute). The thermo-mechanical properties of these materials have been studied in comparison with those ones of composites obtained with the same thermosetting resin reinforced with chopped virgin carbon fibers.

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Cadevall, Riera Miquel. "Bismuth based (nano)materials and platforms for (bio)sensing." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/285769.

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La tesi està basada en la fabricació de nous sensors i biosensors per a la detecció de contaminants. Els micro i nanomateials basats en bismut semblen ser materials molt apropiats per aconseguir aquest objectiu, tanmateix també s’han proposat altres plataformes sensores. En el primer capítol es descriuen detalladament els principals objectius d’aquesta tesi. La introducció d’aquesta tesi descriu les aplicacions més recents i rellevants basades en la utilització de nanomaterials de bismut, com ara en els camps de la medicina, la fotodegradació de contaminants orgànics, la cosmètica, els pigments o els aliatges. Aquesta part precedeix la descripció dels mètodes de síntesi més innovadors, dels sensors més eficients, bàsicament de metalls pesants, i de les aplicacions en el camp dels biosensors. Aquest recull es pot trobar al capítol 2. Les nanopartícules de bismut són una bona plataforma per a sensors i biosensors. En aquest sentit s’ha estudiat la modificació d’elèctrodes serigrafiats amb nanopartícules de bismut. En el capítol 3, s’avaluen diferents mètodes de síntesi de nanopartícules de bismut amb l’objectiu d’obtenir les nanopartícules més eficients en la detecció de metalls pesants; en aquest cas centrat en la detecció de cadmi i plom. Al capítol 4 es presenta una nova estratègia de modificació d’elèctrodes. Aquesta estratègia es basa en la utilització de nanopartícules core-shell. Tenint en compte l’avantatge que dóna el recobriment de bismut, aquestes nanopartícules s’han utilitzat en la detecció de metalls pesants en diferents plataformes sensores. La bona modificació d’aquests elèctrodes es demostra clarament fent cicles de modificat i neteja; el comportament d’aquests elèctrodes modificat es podria considerar com a una resposta digital. L’última plataforma sensora per a metalls pesants proposada es basa en xips de paper. El capítol 5 descriu la fabricació i optimització d’aquests dispositius. Aprofitant la capacitat de filtrar del substrat de paper de filtre, aquestes simples plataformes són capaces de detectar plom i cadmi en diferents matrius, com ara solució tampó, aigua de mar o fangs. En aquest últim capítol es mostra la integració de les nanopartícules de bismut en un biosensor de fenol, basat en l’activitat enzimàtica de la tirosinasa. El capítol 6 inclou la caracterització morfològica i electroquímica del sensor. Aquests elèctrodes modificats amb nanopartícules de bismut i tirosinasa tenen una molt bona resposta en la detecció de fenol i catecol i un baix efecte de les interferències. Finalment al capítol 7 hi ha les conclusions generals i les futures perspectives que obre aquest treball. En els annexos s’hi pot trobar una descripció dels mètodes de fabricació de les diferents plataformes sensores, les abreviatures utilitzades i la producció científica derivada d’aquest treball. The thesis is focused on the fabrication of new sensing and biosensing platforms for pollutants detection. Although bismuth-based micro and nanomaterials seem to be the appropriated materials to achieve this objective nevertheless new platforms including for example those based on paper are also proposed. In the first chapter the main objectives of this thesis are described in detail. The introduction part (chapter 2) of this thesis is dedicated to the revision of the recent reports / achievements on bismuth-based nanomaterials in different application fields that include medicine, photodegradation of organic pollutants, cosmetics, pigments and alloys. An important section of this part is focused on the description of the effect of bismuth-based materials in heavy metals and biosensing applications. Bismuth nanoparticles are found as an innovative material in heavy metals sensing and biosensing applications. A study on the effect of the modification of screen-printed electrodes with bismuth nanoparticles and its use for the heavy metal detection is shown (chapter 3). Different modifications of polyol based bismuth nanoparticles synthesis have been evaluated in aim to obtain the more efficient nanoparticles with interest in heavy metal sensing. In addition the results obtained for the detection of lead and cadmium is also shown in the same chapter. In the chapter 4 a new electrode modification strategy is presented. This new strategy is based on the use of magnetic core/shell bismuth nanoparticles. Taking advantages of the bismuth oxide presence onto the shell of these nanoparticles, heavy metal detection in different On-Off sensing platforms is shown. The modification of electrodes is clearly demonstrated by doing cycles with both modification and cleaning of the electrodes obtaining a kind of digital (On-Off) response of heavy metals. To solve sampling and sample pretreatment issues a heavy metal sensing platform that uses a paper-based lateral flow chip is also developed and described at chapter 5. Fabrication and the optimization of this new heavy metal sensor are shown; it takes advantage of the use of a filter paper substrate. This new platform is capable to detect lead and cadmium in different matrixes including mud. In the last chapter (chapter 6), the integration of bismuth nanoparticles into a phenol biosensing system is shown. It takes advantages of the use of tyrosinase enzyme which brings certain selectivity in phenolic compounds detection. Morphological and electrochemical characterizations of the developed biosensor also are shown in this chapter. The developed biosensor shows good performance in catechol detection. Finally in the chapter 7 the general conclusions and some future perspectives are given.

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Uusi-Tarkka, Eija Katariina. "Bio-based nonwoven fabric-like materials produced by paper machines." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-10690.

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The purpose of this thesis is, in collaboration with the Swedish company Innventia, to explore the possibilities of using paper machines to create fabric-like nonwoven materials. As part of a relatively new research-area, it serves as some of the ground knowledge that is needed to drive this field forward. The research of this thesis is born from the increasing need for more environmental friendly textiles, and to find new uses for the paper production facilities and companies that are currently experiencing a decline in paper production. The materials used in the research were produced with the Finnish handsheet former and the StratEx sheet-maker made by Innventia. The research consists of the following tests: Tissue Softness Analysis, (TSA), tensile strength and bending stiffness. The tests are done with different combinations of lyocell, PLA, softwood and dissolving pulp in the tested sheets. It is also tested if the lyocell can be a meaningful substitution for PLA in combination with softwood pulp and dissolving pulp when creating the fabric-like materials. In conclusion of this research it can be said that, compared to benchmarking samples like bedding sheets, table cloths and cotton shirts, the sheets created and tested are competitive alternatives to existing materials when it comes to softness. It also became clear that the tensile strength has to be increased to make fabric-like nonwoven materials applicable on the same level as existing textiles. Even so, it is still evident that there is a potentiality in the use of paper machines in the development and creation of new fabric-like materials.

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Deans, Taneisha. "Using Nature as a way to Flame Retard Synthetic Materials." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case149154227971565.

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Balogh, Margareta Cristina. "New luminescent materials, bio-inspired and recyclabe, based on lanthanide complexes." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEN039.

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L’objectif de ce projet a été de concevoir des matériaux émissifs recyclables à base de lanthanide, en vue de remplacer les oxydes contenus dans les lampes fluoro-compactes (CFLs). Les lanthanides, en particulier l’Eu¹¹¹ et le Tb¹¹¹ ont été les principaux « ingrédients » dans les phosphores à cause de leurs émissions fines dans le rouge et le vert. Les complexes tris-dipicolinate de lanthanides, solubles dans l’eau sont connus pour leurs excellentes propriétés de luminescence, ce qui en fait de bons candidats pour des applications dans le domaine de l’éclairage.Cette thèse décrit l’étude des complexes de tris-dipicolinate d’Eu¹¹¹ et de Tb¹¹¹ sous forme cristalline avec différents contre-cations, ainsi que des systèmes plus complexes comme des co-cristaux ou des de cristaux cœur/coquille. Ces complexes ont également été utilisés comme dopant dans des silices mésostructurées en utilisant une méthode dites de « incipient wet impregnation » (IWI). Les propriétés photophysiques de ces matériaux ont été étudiées en détail et une forte exaltation des propriétés d’émission a été mise en évidence dans les silices. En particulier, l’influence des oscillateurs O-X a été montrée et la détermination du rendement quantique intrinsèque nous a procuré une meilleure compréhension de cette exaltation.La recyclabilité des complexes de lanthanide dans la silice a pu être réalisée avec des bons rendements. Des matériaux, émettant de la lumière blanche ont pu être obtenus en mélangeant des émetteurs rouge, vert et bleu. Le naphtalimide a été choisi comme émetteur bleu. Ainsi, le mélange des complexes d’Eu¹¹¹ et de Tb¹¹¹ et de naphtalimide au sein d’une silice mésoporeuse a conduit à la première génération de matériaux émettant de la lumière blanche et pouvant être facilement recyclés The objective of this project was to explore recyclable lanthanide based materials suitable for replacing the oxides from compact fluorescent lamps (CFLs). Lanthanides, particularly Eu¹¹¹ and Tb¹¹¹ have been the main “ingredients” in phosphors due to their colour purity and sharp emission in the red and green range of the visible spectrum. Lanthanide tris-dipicolinates are water soluble complexes, known for their excellent photophysical properties which makes them great candidates for lighting. The thesis describes the study of Eu¹¹¹ and Tb¹¹¹ tris-dipicolinate complexes in the crystalline form with different cations, as well as more complex systems like mixed co-crystals and core/shell crystals. The Eu¹¹¹ and Tb¹¹¹ complexes were also used as dopant in mesostructured silica materials via an incipient wetness impregnation method leading to homogeneous materials. The photophysical properties these different materials were thoroughly studied and a significant exaltation of the emission was evidenced in the silica. In particular, the influence of the O-X oscillators was explored and determination of the intrinsec quantum yield gave a clearer image on this exaltation. The recyclability of the lanthanide complexes from the material has been proven with high rates. Finally, white light emitting materials were obtained by mixing red, green and blue emitters. The naphthalimide moiety was chosen as blue emitter and white luminescence was successfully obtained in the solid state and for a silica material, representing a first generation of recyclable white light emitting materials based on lanthanide tris-dipicolinate complexes

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Hapuarachchi, Tharindu Dhanushka. "Development and characterisation of flame retardant nanoparticulate bio-based polymer composites." Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/532.

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Since the discovery of carbon nanotubes (CNTs) and nanoclays, there has been a great deal of research conducted for uses in applications such as: energy storage, molecular electronics, structural composites, biomedical to name but a few. Owing to their unique intrinsic properties and size means that they have an ever growing potential in the consumer and high technology sectors. In recent years the concept of using these as fillers in polymers has shown great potential. One such function is, as flame retardant additives. These possess much better environmental credentials than halogenated based additives as well as only needing to use a small loading content compared to traditional micron sized fillers. The combination of the above make these fillers ideal candidates for polymers and their composites. Especially with regards to natural fibre composites. Owing to environmental awareness and economical considerations, natural fibre reinforced polymer composites seem to present a viable alternative to synthetic fibre reinforced polymer composites such as glass fibres. However, merely substituting synthetic with natural fibres only solves part of the problem. Therefore selecting a suitable material for the matrix is key. Cellulose is both the most common biopolymer and the most common organic compound on Earth. About 33 % of all plant matter is cellulose; i.e. the cellulose content of cotton is 90 % and that of wood is 50 %. However just like their synthetic counterparts, the poor flame retardancy of bio-derived versions restricts its application and development in important fields such as construction and transportation. Abstract -vi- Traditional methods to improve the flame retardancy of polymeric material involve the use of the micron sized inorganic fillers like ammonium polyphosphate (APP) or aluminium trihydroxide (ATH). Imparting flame retardancy with these inorganic fillers is possible but only with relatively high loadings of more than 50 wt. %. This causes detrimental effects to the mechanical properties of the composite and embrittlement. Applying nanofillers can achieve similar if not better flame retarding performances to their micron sized counterparts but at much lower loading levels (<10 wt.%), thus preserving better the characteristics of the unfilled polymer such as good flow, toughness, surface finish and low density. This is the main focus of this study and it will be achieved by using various experimental techniques including the cone calorimeter and the newly developed microcalorimeter. After a comprehensive literature survey (Chapter 2), the experimental part of the thesis starts with a feasibility study of a flame retardant natural reinforced fibre sheet moulding compound (SMC) (Chapter 3). This work demonstrated that with a suitable flame retardant the peak heat release rate can be reduced. Chapter 4 deals with further improving the flame retardancy of the previously used unsaturated polyester resin. The aim is to study any synergistic behaviour by using aluminium trihydroxide in conjunction with ammonium polyphosphate whilst testing in the cone calorimeter. In Chapter 5, nanofillers are used to replace traditional micron sized fillers. In unsaturated polyester, multi-walled carbon nanotubes and sepiolite nanoclay are used together to create a ternary polymer nanocomposite. The microcalorimeter was employed for screening of the heat release rate. This work showed that the ternary nanocomposite showed synergistic behaviour with regards to significantly reducing the peak heat release rate. Abstract -vii- The same nanofillers were utilised in Chapters 6 and 7 but this time in combination with a thermoplastic (polypropylene) and bio-derived polymer (polylactic acid), respectively. In both systems an improved flame retardancy behavior was achieved whist meeting the recyclability objective. Chapter 8 attempts to show how the optimised natural fibre composite would behaviour in a large scale fire test. The ConeTools software package was used to simulate the single burning item test (SBI) and to classify the end product. This is a necessity with regards to commercialising the product for consumer usage. Finally, Chapter 9 is a summary of the work carried out in this research as well as possible future work that should be conducted.

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Seng, Billy. "Etude expérimentale et numérique du comportement hygrothermique de blocs préfabriqués en béton de chanvre." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30153.

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Le béton de chanvre est un matériau de construction biosourcé pouvant répondre aux problématiques environnementales actuelles. Utilisé comme matériau de remplissage avec une bonne capacité isolante, il possède également la capacité de réguler l'humidité relative intérieure. Son comportement hygrothermique complexe résulte notamment de performances thermiques et hydriques interdépendantes. La prédiction de ces effets est réalisée à l'aide de modélisation et simulation de transferts hygrothermiques. Toutefois, l'utilisation de données d'entrée les plus représentatives possibles de la réalité est nécessaire. Les méthodes de caractérisation courantes ont souvent été développées pour des matériaux conventionnels et peuvent montrer des limites dans le cas de matériaux biosourcés. L'objectif principal de ces travaux est de déterminer les propriétés hygrothermiques d'un bloc de béton de chanvre préfabriqués à l'échelle industrielle, de mieux appréhender cette caractérisation et de décrire son comportement hygrothermique via des simulations numériques. Le matériau étudié est formulé à partir d'un liant pouzzolanique et de granulats de chènevotte. Une partie de ce travail de thèse a donc porté sur la caractérisation des propriétés physiques, thermiques et hydriques du béton de chanvre étudié ainsi que sur les méthodes de mesure. Pour chaque paramètre hygrothermique étudié, plusieurs méthodes ont été confrontées afin d'en évaluer l'impact. Dans la mesure du possible, l'influence de la température et de l'humidité sur les différents paramètres a également été estimée. Un modèle de transferts hygrothermiques est proposé avec une évaluation d'ordre de grandeur dans le cas du béton de chanvre à partir des propriétés de la littérature. Ce modèle est appliqué à une étude expérimentale à l'échelle de la paroi, dans une enceinte bi-climatique, mettant en avant l'impact de la sorption et du changement de phase sur les transferts de chaleur. En ce qui concerne les propriétés thermiques, l'étude expérimentale à l'échelle du matériau met en évidence l'impact significatif du protocole expérimental sur le résultat de mesure, en particulier pour la chaleur massique. Pour les propriétés hydriques, les essais mettent en avant l'intérêt de réaliser une étude paramétrique de type round-robin sur les matériaux biosourcés. [...] Hemp concrete is a bio-based construction material able to meet current sustainable issues. Used as filling and insulating material, it has the capacity to regulate the indoor relative humidity. Its complex hygrothermal behavior results on interdependent thermal and hydric performances. The prediction of the hygrothermal effect is performed through heat and moisture transfer modeling and simulation. However, the use of representative inputs is necessary. Standard characterization methods have often been developed for usual building material and can show some limitations in the case of bio-based material. The main objective of these works is to determine the hygrothermal properties of a precast hemp concrete produced at industrial scale, have a better understanding of this characterization and describe its hygrothermal behavior through numerical simulations. The studied material is based on pozzolanic binder and hemp aggregates. One part of this work deals with the characterization of the physical, thermal and hydric properties of the studied material and with the measurement methods. For each hygrothermal properties, several methods have been confronted. If possible, the temperature and humidity influences have been appraised. A heat and moisture transfer model is proposed with a scale analysis based on hemp concrete properties from the literature. This model has been applied to wall scale experiments highlighting the impact of sorption and phase change phenomena on the heat transfers. With regards to the thermal properties, the experimental study at material scale highlights the significant impact of the experimental protocol on the result of the measure, particularly for the specific heat capacity. For hydric properties, the studies put forward the interest of performing a parametric round-robin test dedicated to bio-based materials. An air permeability measurement protocol designed for regular concrete has been adapted in order to evaluate the performance of a very permeable material such as the hemp concrete. The numerical model is validated on a test from a standard and a test from the literature. It manages to describe test with usual ambient solicitations performed in the bi-climatic chamber

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Schinazi, Gustavo. "Bio-Based Flame Retardation of Acrylonitrile-Butadiene-Styrene." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1605795004534958.

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Doroudgarian, Newsha. "High performance bio-based composites : mechanical and environmental durability." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/392719.

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The presented work is a part of the ongoing effort on the development of high performance bio-based composites with enhanced durability, under static and dynamic mechanical loading including the exposure to elevated humidity. The impact of relative humidity on the performance of cellulosic fibers (natural and regenerated), bio-based resins and their composites was studied. The material performance was rated against the data for glass fiber epoxy, as the reference. The comparison of water absorption results for unreinforced resins and for composites showed that the cellulosic reinforcement is primarily responsible for the transport and uptake of moisture in the composites. The effect of chemical treatment on the cellulosic fibers, as a protection against moisture, was evaluated. However, the treatment did not improve the moisture resistance in composites significantly. Quasi-static tensile tests revealed that some of the bio-based resins and their composites performed very well and comparable to the composites of synthetic epoxy, even at high humidity. However, any structural material is supposed to hold mechanical loads over a long service time and most often in harsh environmental conditions. Hence, tension-tension fatigue tests were performed on the fiber bundles as well as on the composites. The fibers of choice as the reinforcement for further mechanical testing were regenerated cellulose fibers (RCF), mainly owing to the stable geometry and properties. Due to the high nonlinearity of RCF, the fatigue tests were limited in number and the focus was on analyzing the mechanisms underlying the fatigue behavior rather than on constructing S-N curves. Strain evolution of the bio-based composites during the dynamic fatigue was very similar to that observed in the static fatigue (creep). It confirmed the strong influence of viscoelastic and viscoplastic phenomena on the overall performance of the material under the rapid loading conditions in fatigue. Since the durability of composites greatly depends on the material¿s ability to stand the internal damages (e.g. debonding, microcracking, delaminations), the interfacial properties in the bio-based composites were addressed. To investigate the fracture toughness of bio-based composites, the double cantilever beam (DCB) tests were carried out, under static and dynamic loading. Moreover, the DCB results were utilized as a measure of the fiber chemical treatment¿s efficiency to improve the adhesion between RCF and the resin. The nonlinearity of RCF strongly influenced the results obtained from DCB tests, which complicated the analysis regarding the effectiveness of the fiber surface treatment. Nevertheless, this study brings forward the issues that have to be dealt with, in order to characterize and predict the performance of these composite materials with highly nonlinear reinforcing fibers. Overall, the results presented in this thesis give an insight into the behavior of bio-based composites, at various environments and under different types of mechanical loading. Based on these findings, the potential use of these materials in structural applications can be assessed

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Claude, Sophie. "Étude expérimentale et numérique de solutions basées sur les éco-matériaux pour la rénovation thermique du patrimoine bâti urbain." Thesis, Toulouse, INSA, 2018. http://www.theses.fr/2018ISAT0008/document.

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Concilier patrimoine et amélioration de la performance énergétique du bâti ancien est un défi pour de nombreux centres historiques. La Communauté d’Agglomération du Grand Cahors, qui finance ce travail de thèse à travers une convention CIFRE, a souhaité s’attaquer à cette problématique en valorisant des isolants bio-sourcés. Le choix du matériau et du système d’isolation sont essentiels car ils influencent à la fois la performance hygrothermique de la paroi, la qualité de l’air intérieur, le coût et l’empreinte carbone de la rénovation. Dans cette étude, nous nous sommes focalisé sur la performance hygrothermique de la paroi afin d’assurer que la mise en place d’une isolation par l’intérieur ne soit pas source de dégradations futures de la paroi. Pour cela, nous avons confronté différents outils et méthodes tels que la caractérisation physique des matériaux, une instrumentation in-situ dans deux appartements du centre ancien de Cahors et des simulations hygrothermiques alliant différents outils numériques Improving the energy efficiency of buildings is essential to reduce greenhouse gas emissions and mitigate against climate change. Historic dwellings represent a large part of the French building stock that needs to be refurbished. In the city center of Cahors, France, the old medieval dwellings are considered as valuable cultural heritage and internal insulation is often the only insulation technique that can be used when the architectural value of the exterior façade is to be preserved. This PhD thesis, funded by a CIFRE agreement with the Communauté d’Agglomération du Grand Cahors, studied the suitability of bio-based materials for the internal insulation of historical dwellings in urban area. The selection of the insulation material and the system is crucial because of its impact on the hygrothermal performance of the wall, the indoor air quality, the financial cost, and the carbon footprint of the refurbishment solution. In this study we focused on the hygrothermal performance of the walls to provide a reliable risk assessment in order to avoid hygrothermal failure. Due to the complexity of the problem and the lack of needed data, we ran a multi-scale study including both experimental (laboratory characterisation and building monitoring) and numerical modelling methods

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Zhao, Lei. "Novel bio-composites based on whole utilisation of wheat straw." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7359.

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This thesis reports research work in the development of biocomposites based on whole utilisation of renewable wheat straw for industrial applications. The concept of “whole utilisation” is based on a previous work on a novel twin-screw extrusion technology for processing of feedstock in wheat straw reinforced bio-composites. It demonstrated that straw raw material could be restructurised into a feedstock with cellulose fibre finely dispersed in the non-cellulose matrix, which can be utilised as a bonding phase without having to be removed as in conventional processes to extract the cellulose. The whole straw can thus be utilised to avoid waste of materials and the negative impacts to environment associated with the extraction process. Raw wheat straw in this research was prepared in three ways: size reduction through mechanical milling, pre-treatment by aqueous NaOH solution and deep preparation with aqueous NaOH solution soaking followed by extrusion fractionation. Prepared wheat straws were processed into varieties of forms according to the applications. They were hot-compressed into self-reinforced composite with good flow ability and also processed through extrusion and compression moulding to compound with other biopolymers as good filler. The relationships of processing parameter and property, as well as formulation and property were established for each form of product, which provides a key understanding of the whole development circle of an end product. Through this research, scientific and technical problems has been addressed in materials formulation/processing, product design/manufacturing, enhancement of functionality/ performance as well as economical/environmental assessment so as to develop a series of cost-effective bio-composites and products, which satisfy diverse technical and environmental performance requirements in the industrial sectors across packaging, horticulture, building/construction and shooting sports.

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Niesbach, Alexander [Verfasser]. "Design of Reactive Distillation Processes Using Bio-based Raw Materials / Alexander Niesbach." München : Verlag Dr. Hut, 2014. http://d-nb.info/1063221722/34.

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Puchot, Laura. "Cardanol : a bio-based building block for new sustainable and functional materials." Thesis, Cergy-Pontoise, 2016. http://www.theses.fr/2016CERG0828/document.

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Récemment, la chimie des ressources renouvelables et les matériaux qui en découlent ont suscités un intérêt considérable dans le but de limiter l’utilisation des ressources fossiles. La présente thèse intitulée « Cardanol : a bio-based building block for new sustainable and functional materials » traite de la modification chimique du cardanol et de son utilisation dans diverses applications. Le cardanol est un dérivé phénolique naturel extrait de l’huile de coque de noix de cajou. Sa structure chimique est intéressante : il est substitué d’une chaîne alkyle en C15, partiellement insaturée, et il est porteur d’une fonction phénol, permettant d’envisager de nombreuses réactions chimiques.La première partie de cette étude traite de la synthèse et de la caractérisation de trois surfactants ammoniums issus du cardanol se différenciant par le degré de substitution de leurs amines. Leur capacité à favoriser l’exfoliation d’une argile lamellaire dans une matrice de type époxy a été étudiée dans le but de concevoir des matériaux composites.Le second chapitre décrit une nouvelle méthode de synthèse de monomères benzoxazines bio-basés et l’élaboration de réseaux polybenzoxazines à partir du cardanol. Une nouvelle génération de monomères benzoxazine, issus du cardanol ou de dérivés de la lignine tels que la vanilline, a récemment été développée. Cependant l’essentiel des benzoxazines bio-basées synthétisées jusqu’à présent sont monofonctionnelles ou présentent des températures de fusion trop élevées. Elles ne permettent donc pas l’élaboration de matériaux autosupportés valorisables. Afin de pallier ce problème, une synthèse originale de monomères benzoxazines asymétriques, reposant sur la combinaison de cardanol et de dérivés de la lignine, est décrite. Les matériaux autosupportés résultants présentent des propriétés améliorées par rapport à celles que ne pourraient atteindre les monomères symétriques issus de ces phénols bio-sourcés.Finalement, le troisième chapitre concerne l’utilisation d’un pré-polymère époxy issu du cardanol pour l’élaboration de matériaux époxy bio-basés. Cependant, en raison de la chaîne alkyle du cardanol, ce nouveau matériau présente une faible Tg et une forte prise en eau. Afin de renforcer ses propriétés thermo-mécaniques et de diminuer sa prise en eau, une modification chimique a été réalisé à l’échelle macromoléculaire par l’élaboration de réseaux interpénétrés de polymères à base de réseaux polybenzoxazines.Ces différents travaux ont permis de mettre en avant la modification aisée et versatile du cardanol, pouvant ainsi résulter en une large variété de synthons bio-basés et des matériaux qui en découlent. Ces travaux ouvrent la voie vers d’autres structures et architectures moléculaires aux applications nombreuses Recently, considerable interest of the chemistry of renewable ressources and their resulting materials has grown with a view to reduce the use of finite petroleum-based resources. The present thesis entitled « Cardanol: a bio-based building block for new sustainable and functional materials » is dealing with the chemical modification of cardanol and its use for various applications. Cardanol is a naturally occurring phenolic compound issued from cashew nutshell liquid. Its chemical structure is interesting because cardanol is bearing a phenolic hydroxyl function and an unsaturated alkyl chain in meta. Numerous chemical reactions can thus be considered for its chemical modification.The first part of this study is dealing with the synthesis and the characterization of three cardanol-based ammonium surfactants differing by their amine functionalities content. Their effectiveness on the exfoliation of silicate clay within an epoxy matrix was investigated with the aim to elaborate composit materials.The second chapter is describing a novel method for the synthesis of bio-based benzoxazine monomers and the elaboration of polybenzoxazine networks issued from cardanol. A new generation of benzoxazine monomers issued from cardanol or from lignin derivatives such as vanillin were recently developed. However, up to now, the majority of the synthetised benzoxazine monomers are mainly mono-functionnal or display too high melting temperatures. The elaboration of valuable self-standing materials is thus strongly impeded. To solve this problem, an innovative synthesis of asymmetric benzoxazine monomers by combination of cardanol and lignin derivatives is described. The resulting self-standing materials display improved properties in comparison to materials issued from symmetric bio-based monomers.Finally, the third chapter realtes to the use of a cardanol-based epoxy pre-polymer for the elaboration of bio-based epoxy materials. Nevertheless, this new material displays low Tg and high water uptake due to the alkyle side chain of cardanol. In order to reinforce the thermo-mechanical properties of the material and to reduce its water uptake, a chemical modification was achieved at the macromolecular scale by the elaboration of interpenetrating polymer networks with polybenzoxazine networks.These various studies allowed to highlight the easy and versatile modification of cardanol, resulting thus in a diversity of bio-based synthons and their resulting materials. This work paves the way to the elaboration of other chemical structures and molecular architectures for various applications

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McConney, Michael Edward. "Learning and applying material-based sensing lessons from nature." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29749.

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Thesis (Ph.D)--Polymer, Textile and Fiber Engineering, Georgia Institute of Technology, 2010. Committee Chair: Tsukruk, Vladimir; Committee Member: Shofner, Meisha; Committee Member: Srinivasarao, Mohan; Committee Member: Thio, Yonathan; Committee Member: Weissburg, Marc. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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Freyburger, Auriane [Verfasser], and Werner [Akademischer Betreuer] Kunz. "Novel bio-based materials from cellulose and chitin / Auriane Freyburger ; Betreuer: Werner Kunz." Regensburg : Universitätsbibliothek Regensburg, 2018. http://d-nb.info/115678042X/34.

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Chen, Chen. "Comparison of Corn and Rye Arabinoxylans for the Production of Bio-based Materials." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-282808.

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Enzymes and subcritical water can be used for the extraction of hemicelluloses from cereal by-products, making the processes eco-friendly. The polysaccharides extracted from cereal by-products can be used as matrices for development of materials for various applications. This includes bio-based materials such as films and hydrogels, which offer alternatives to existing materials produced from petrochemicals. The polymeric structure of cereal hemicelluloses contains functional groups which enable the modification of their structure by cross-linking, resulting in the formation of hydrogels. This project aims to use subcritical water extraction (SWE) to extract arabinoxylans (AXs) from corn and rye bran meanwhile the enzymatic treatment is done for purifying the samples during both pre- and post-treatment. AXs were further crosslinked by enzyme (laccase) for hydrogel preparation. During the whole project, the characterization included moisture and yield determination, starch and protein content which were tested using a spectrophotometer, monosaccharide content was analyzed by high performance anion exchange chromatography followed by pulsed amperometric detection (HPAEC-PAD) and phenolic acid content was quantified by high performance liquid chromatography (HPLC). The pretreatment for destarching and SWE process was successful. The result showed that arabinoxylans form corn bran were having higher content of arabino substituents, arabino toxylans ratio and ferulic acid content than rye samples. The enzymatic crosslinking could form strong gels in the condition that the AXs had high ferulic acid content. In terms of forming strong hydrogels or to improving the properties of AXs gel, the pre- and post-treatment should be optimized to increase the purity of the extracted feruloylated AX content. Enzymer och subkritiskt vatten kan användas för extraktion av hemicellulosa från spannmålsbiprodukter, vilket gör extraktionen miljövänlig. Polysackariderna extraherade från spannmålsprodukter kan användas som matriser för utveckling av material för diverse applikationer. Detta inkluderar biobaserade material som filmer och hydrogeler, där petrokemikalier kan ersättas som råvara. Den polymera strukturen hos spannmålshemicelluloser innehåller funktionella grupper som möjliggör formation av tvärbindningar vilket resulterar i bildandet av hydrogeler. Syftet med detta projekt är extraktion av arbinoxylaner (AXs) från majs och rågkli genom att använda subkritiskt vatten-extraktion (SWE) där rening under för- och efterbehandling utförs enzymatiskt. AX modifierades därefter enzymatiskt (laccas) med tvärbindningar för hydrogelframställning. Under hela projektet karakteriserades hydrogelen utifrån fuktinnehåll, bestämmelse av utbyte, stärkelse och proteininnehåll som testades med en spektrofotometer, monosackaridhalten analyserades med högpresterande anjonsutbyteskromatografi följt avpuls-amperometrisk detektion (HPAEC-PAD), samt kvantifierades fenolsyrahalten med högupplöst vätskekromatografi (HPLC). Resultatet visade att arabinoxylaner från majskli hade högre innehåll av arabinosubstituenter, där förhållandet mellan arabino och xylans, samt arabino och ferulsyra innehållet var högre än för rågproverna. Den enzymatiska tvärbindningen kunde bilda starka geler i det tillståndet där AX hade en hög ferulsyrahalt. När det gäller att bilda starka hydrogeler eller att förbättra egenskaperna hos AXs-gel, bör för-och efterbehandlingen optimeras för att öka renheten fördet extraherade feruloylerade AX-innehållet.

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Xiao, Ming. "BIO-INSPIRED MELANIN-BASED STRUCTURAL COLORS THROUGH SELF-ASSEMBLY." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron149927021458423.

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Le, Corre Déborah. "Starch nanocrystals : preparation and application to bio-based flexible packaging." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENI073/document.

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Ce travail examine la potentielle mise à l'échelle industrielle des procédés de préparation des nanocristaux d'amidon (SNCs). Une caractérisation approfondie (morphologie, viscosité, stabilité thermique et propriétés en nanocomposites) de 5 SNCs différents montre une faible influence de la source botanique, contrairement aux nanocristaux de cellulose. L'analyse du procédé de préparation actuel des SNCs a conduit à 3 nouvelles stratégies d'optimisation et à la définition d'une nouvelle génération de SNCs. Une nouvelle application des SNCs, en emballage multicouche, montre également que les SNCs peuvent être utilisés en couchage et contribuer à diminuer la perméabilité à la vapeur d'eau de certains biopolymères. Une analyse du cycle de vie des SNCs dans ce type d'application est également proposée. Cette étude contribue donc à l'avancée de cette thématique et propose des perspectives prometteuses The present work investigates the potential of starch nanocrystals (SNCs) for industrial scaled-up preparation and use. An extensive characterization (morphology, viscosity, thermal stability and properties in nanocomposite) of 5 different SNCs shows, contrary to nanocrystalline cellulose, the limited influence of the botanic source. The analysis of the current preparation process led to three optimization strategies, and to the definition of a new generation of SNCs with smaller dimensions and more homogeneous. A new application of SNCs is presented (multilayer packaging); and showed that SNCs can effectively reduce water vapor permeability of some biopolymers coatings. The life cycle assessment (LCA) of SNCs in this application is also proposed. This study contributes greatly to the advance of the field and offers perspectives for the industrialization of SNCs

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Claudino, Mauro. "Thiol−ene Coupling of Renewable Monomers : at the forefront of bio-based polymeric materials." Licentiate thesis, KTH, Ytbehandlingsteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-40267.

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Plant derived oils bear intrinsic double-bond functionality that can be utilized directly for the thiol–ene reaction. Although terminal unsaturations are far more reactive than internal ones, studies on the reversible addition of thiyl radicals to 1,2-disubstituted alkenes show that this is an important reaction. To investigate the thiol–ene coupling reaction involving these enes, stoichiometric mixtures of a trifunctional propionate thiol with monounsaturated fatty acid methyl esters (methyl oleate or methyl elaidate) supplemented with 2.0 wt.% Irgacure 184 were subjected to 365-nm UV-irradiation and the chemical changes monitored. Continuous (RT– FTIR) and discontinuous (NMR and FT–Raman) techniques were used to follow the progress of the reaction and reveal details of the products formed. Experimental results supported by numerical kinetic simulations of the system confirm the reaction mechanism showing a very fast cis/trans-isomerization of the alkene monomers (<1.0 min) when compared to the total disappearance of double-bonds, indicating that the rate-limiting step controlling the overall reaction is the hydrogen transfer from the thiol involved in the formation of final product. The loss of total unsaturations equals thiol consumption throughout the entire reaction; although product formation is strongly favoured directly from the trans-ene. This indicates that initial cis/trans-isomer structures affect the kinetics. High thiol–ene conversions could be easily obtained at reasonable rates without major influence of side-reactions demonstrating the suitability of this reaction for network forming purposes from 1,2-disubstituted alkenes. To further illustrate the validity of this concept in the formation of cross-linked thiol–ene films a series of globalide/caprolactone based copolyesters differing in degree of unsaturations along the backbone were photopolymerized in the melt with the same trithiol giving amorphous elastomeric materials with different thermal and viscoelastic properties. High thiol–ene conversions (>80%) were easily attained for all cases at reasonable reaction rates, while maintaining the cure behaviour and independent of functionality. Parallel chain-growth ene homopolymerization was considered negligible when compared with the main coupling route. However, the comonomer feed ratio had impact on the thermoset properties with high ene-density copolymers giving networks with higher glass transition temperature values (Tg) and a narrower distribution of cross-links than films with lower ene composition. The thiol–ene systems evaluated in this study serve as model example for the sustainable use of naturally-occurring 1,2-disubstituted alkenes at making semi-synthetic polymeric materials in high conversions with a range of properties in an environment-friendly way. Vegetabiliska oljor som innehåller dubbelbindningar kan användas direkt för thiolene reaktioner. Trots att terminala dubbelbindningar är mycket mer reaktiva än interna visar dessa studier att den reversibla additionen av thiyl radikaler till 1,2-disubstituerade alkener är en viktig reaktion. För att undersöka tiol–ene reaktionerna, som ivolverar dessa alkener förbereddes stökiometriska blandningar av en trifunktionell propionat tiol och enkelomättade fettsyrametylestrar (metyloleat eller metyl elaidat) samt 2.0 vikt.% Irgacure 184. Dessa blandningar utsattes för 365-nm UV strålning och de kemiska förändringarna studerades. De kemiska förändringarna analyserades med olika kemiska analysmetoder; realtid RT–FTIR, NMR och FT–Raman. Dessa användes för att analysera de kemiska reaktionerna i realtid och följa bildandet av produkterna. Reaktionsmekanismen bekräftades med hjälp av experimentella data och beräkningar av numeriska och kinetiska simuleringar för systemet. Resultaten visar en mycket snabb cis/trans-isomerisering av alkenmonomeren (<1.0 min) jämfört med den totala förbrukningen av dubbelbindningarna, vilket indikerar att det hastighetsbegränsande steget kontrolleras av väteförflyttningen från tiolen till slutprodukten. Förbrukningen av den totala omättade kolkedjan är lika med tiolförbrukningen under hela reaktionen, även om bildandet av produkten gynnas från trans-enen. Detta indikerar att den första cis/trans-isomerstrukturen påverkar kinetiken. Höga tiol-ene utbyten kan enkelt erhållas relativt snabbt utan inverkan av sidoreaktioner. Detta innebär att denna reaktion kan användas som nätverksbildande reaktion för flerfunktionella 1,2-disubstituted alkenmonomerer. Vidare användes fotopolymerisation i smälta på en serie globalid/kaprolaktonbaserade sampolyestrar med varierad grad av omättnad med samma tritiol vilket resulterade i bildandet av amorfa elastomeriska material med olika termiska och viskoelastiska egenskaper. Hög omsättning (>80%) uppnåddes relativt enkelt för samtliga blandningar oberoende av den initiala funktionaliteten. Homopolymerisation av alkenen var försumbar i jämförelse med den tiol–en-reaktionen. Mängden alkengrupper har inverkan på härdplastsegenskaperna där en hög andel alken ger en nätstruktur med högre glastransitionstemperatur (Tg). Tiol–ene reaktionen utvärderades i modellsystem baserade på naturlig förekommande 1,2-disubstituterade alkener för att demonstrera konceptet med tiol-förnätade halvsyntetiska material. QC 20110915

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Hussain, Atif. "Enhancement of hygrothermal properties of bio-based thermal insulation materials via sol-gel technology." Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767569.

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This study involves the modification of a bio-based aggregate, hemp shiv, using functionalised silica-based coatings. This is the first time sol-gel technology is used in the treatment of hemp shiv to develop sustainable thermal insulation building materials with enhanced hygrothermal properties. Bio-based materials such as hemp shiv have a tendency to absorb large amounts of water due to their hydrophilic nature and highly porous structure. In contrast, the high porosity of hemp shiv provides excellent moisture buffering and thermal insulating properties. In this work, the hydrophilicity of the hemp shiv was reduced without compromising its moisture buffering ability. A detailed investigation into the physical and chemical properties, surface roughness, porosity and microstructure of hemp shiv is presented. Application of coatings on hemp shiv was found to alter the properties of hemp shiv. The focus of this work was to particularly enhance the water-resistance of hemp shiv without significantly altering the morphology and microstructure of hemp shiv. The coatings were formulated by the cohydrolysis and polycondensation of tetraethoxyorthosilicate (TEOS). The effect of methytriethoxysilane (MTES) and hexadecyltrimethoxysilane (HDTMS) as functionalising agents in the coating was evaluated. The impact of precursors and their concentration in the coating formulation showed varying results on the hydrophobicity and roughness of hemp shiv. Furthermore, the porosity of hemp shiv was affected by the number of coating layers thereby blocking the pores responsible for the moisture buffering behaviour of hemp shiv. The selected coating formulation was found to increase the hydrophobicity of hemp shiv providing water contact angles up to 118° and reducing the water absorption rates by 250% without showing a significant reduction in the moisture absorption capacity. Novel thermal insulation building composites were developed using the coated hemp shiv in both a silica and a starch-based matrix. The composites were characterised for their hygrothermal, physical and mechanical properties where it was found that the sol-gel coating reduced water absorption capacity without affecting the moisture buffering ability of the composites. The newly designed light weight high performance composites have potential as sustainable thermal insulators and can establish innovative concepts for global application.

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Modi, Sunny J. "A novel use of bio-based natural fibers, polymers, and rubbers for composite materials." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1403205265.

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Krikorian, Vahik. "Bio-nanocomposites fabrication and characterization of layered silicate nanocomposites based on biocompatible/biodegradable polymers / by Vahik Krikorian." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file , 11.06 Mb, 148 p, 2005. http://wwwlib.umi.com/dissertations/fullcit/3187609.

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Svagan, Anna. "Bio-inspired cellulose nanocomposites and foams based on starch matrix." Doctoral thesis, KTH, Biokompositer, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9666.

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In 2007 the production of expanded polystyrene (EPS) in the world was over 4 million tonnes and is expected to grow at 6 percent per year. With the increased concern about environmental protection, alternative biodegradable materials from renewable resources are of interest. The present doctoral thesis work successfully demonstrates that starch-based foams with mechanical properties similar to EPS can be obtained by reinforcing the cell-walls in the foams with cellulose nanofibers (MFC). High cellulose nanofiber content nanocomposites with a highly plasticized (50/50) glycerol-amylopectin starch matrix are successfully prepared by solvent-casting due to the high compatibility between starch and MFC. At 70 wt% MFC, the nanocomposites show a remarkable combination of high tensile strength, modulus and strain to failure, and consequently very high work to fracture. The interesting combination of properties are due to good dispersion of nanofibers, the MFC network, nanofiber and matrix properties and favorable nanofiber-matrix interaction. The moisture sorption kinetics (30% RH) in glycerol plasticized and pure amylopectin film reinforced with cellulose nanofibers must be modeled using a moisture concentration-dependent diffusivity in most cases. The presence of cellulose nanofibers has a strong reducing effect on the moisture diffusivity. The decrease in zero-concentration diffusivity with increasing nanofiber content could be due to geometrical impedance, strong starch-MFC molecular interaction and constrained swelling due to the cellulose nanofiber network present. Novel biomimetic starch-based nanocomposite foams with MFC contents up to 40 wt% are successfully prepared by freeze-drying. The hierarchically structured nanocomposite foams show significant increase in mechanical properties in compression compared to neat starch foam. Still, better control of the cell structure could further improve the mechanical properties. The effect of cell wall composition, freeze-drying temperature and freezing temperature on the resulting cell structure are therefore investigated. The freeze-drying temperature is critical in order to avoid cell structure collapse. By changing the starch content, the cell size, anisotropy ratio and ratio between open and closed cells can be altered. A decrease in freezing temperature decreases the cell size and increases the anisotropy ratio. Finally, mechanical properties obtained in compression for a 30 wt% MFC foam prepared by freeze-drying demonstrates comparable properties (Young's modulus and yield strength) to expanded polystyrene at 50% RH and similar relative density. This is due to the reinforcing cellulose nanofiber network within the cell walls. QC 20100913

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Garst, Sebastian, and n/a. "Design and production of polymer based miniaturised bio-analytical devices." Swinburne University of Technology, 2007. http://adt.lib.swin.edu.au./public/adt-VSWT20071003.082618.

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The aim to provide preventive healthcare and high quality medical diagnostics and treatment to an increasingly ageing population caused a rapidly increasing demand for point-of-care diagnostic devices. Disposables have an advantage over re-usable units as cross-contamination is avoided, no cleaning and sterilising of equipment is required and devices can be used out of centralised laboratories. To remain cost-effective, costs for disposables should be kept low. This makes polymer materials an obvious choice. One method for the realisation of fluidic micro devices is the stacking of several layers of microstructured polymer films. Reel-to-reel manufacturing is a promising technique for high-volume manufacturing of disposable polymer bio-analytical devices. Polyethylene terephthalate (PET) and cycloolefin copolymer (COC) were selected as suitable polymer substrate materials and polydimethyl siloxane (PDMS) as membrane layer. Bonding of polymer films with the help of adhesives carries the risk of channel blocking. Despite this drawback, no other method of bonding PDMS to a structural layer could be identified. Bonding with solvents avoids channel blocking issues, but adversely affects biocompatibility. Thermal diffusion processes enable bonding of COC and PET without the use of any auxiliary material. The extensive process times requires for thermal diffusion bonding can be considerably shortened by pre-treating the material with plasma or UV exposure. Welding with the use of a laser energy absorbing dye was demonstrated to be particularly suitable for selective bonding around channels and reservoirs. None of the assessed bonding methods provide a generic solution to all bonding applications. Instead, the selection of an appropriate technique depends on the intended application and the required level of biocompatibility. Since this selection has implications on the feasibility and reliability of microfluidic structures on the device, design rules which ensure design for production have to be established and followed.

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Dissertations / Theses on the topic 'Bio-based material'

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