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KHAN, FAHAD AHMAD. "Developing Robot assisted Plastic 3D Printing Platform." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-295472.
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This project was initiated by Dr. Sasan Dadbaksh upon listening to the requirements I presented for my master thesis. My requirements were to do a master thesis project in the field of additive manufacturing specifically fused deposition modeling that should not only involve the research work but should also present an opportunity to develop hardware and should involve experimental testing. Then Sasan came up with the idea of developing a system capable to perform 3D printing with the extruder fixed in one position and the motion required for 3D printing will be provided by the robotic arm. The title of developing green build strategies for robot assisted plastic 3D printing came into being. The main concept behind the title of developing robot assisted plastic 3D printing platform is to develop such a system that can offer additive manufacturing services, specifically of fused deposition modeling 3D printing, as an inbound process during the manufacturing of any part through subtractive processes with the help of a robotic arm along with the repair of any kind of parts with the assistance of fused deposition modeling 3D printing. The main objectives of the master thesis include building a stationary filament extrusion module to interact with a robot hand and establishing a strategy for a robot hand to move the part to appropriate locations to complete building a part on a preform without support structures. The targets that were achieved with the completion of this thesis project includes the development of the complete hardware that consists of a mechanical structure with the option of mounting the components required to run the extrusion setup, learning the basic working of the software that are able to simulate the 3D printing process with the robotic arm (Robot Studio and Robo DK), creation of the simulation of the whole process, achieving communication between the robotic arm and the microcontroller of the extruder and finally the printing of a simple part for the demonstration. The components needed to be installed on the structure includes the motor, extruder, hot end, nozzle, filament. The structure also accumulated the required electronics that includes power supply, microcontroller, and an LCD to monitor the extrusion parameters. The developed machine runs on the state-of-the-art components that belong to the few of the best manufacturers of the technology.
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Peña, del Olmo Magali Noemi. "Additive manufacturing of non plastic porcelain material by direct writing and freeze casting." Thesis, De Montfort University, 2011. http://hdl.handle.net/2086/5620.
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Two direct consolidation methods usually used for advanced ceramics have been combined in this project in order to develop a novel fabrication route for traditional ceramics. Specifically the method used is based on the Additive Manufacturing extrusion process using direct writing of high solid loading ceramic pastes and then freeze-casting to solidify the deposited material. This novel fabrication method, for which a patent has been granted, has been christened “Direct Writing Freeze-Casting” (DWFC). Although the DWFC process is the subject of investigation by other researchers for a range of different applications, including the production of medical implants with alumina, the research presented in this thesis focuses on its use in the manufacture of white wares, giftware, and applied arts and crafts in general. This new system will provide designers, potters, artists, craft makers and manufacturers with a flexible and automated way of manufacturing porcelain objects. One of the major challenges to be overcome to exploit the DWFC process is the development of suitable slurry material formulations. Initial trials demonstrated that it is not possible to use conventional clay based porcelain materials with a platelet shaped microstructure which inhibits freeze casting. In this thesis the development and characterisation of non plastic porcelain slurry, based on substitution of kaolin (clay) with a calcined clay material (molochite), which can be processed using this new method is presented. The new non plastic porcelain formulation, which has a high solid load of 75.47% wt., has been subjected to detailed analysis to assess its suitability at each stage of the process; extrusion, freeze-casting (solidification) and firing.
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Griffiths, Robert Joseph. "Dynamic and Post-Dynamic Microstructure Evolution in Additive Friction Stir Deposition." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104664.
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Metal additive manufacturing stands poised to disrupt multiple industries with high material use efficiency and complex part production capabilities, however many technologies deposit material with sub-optimal properties, limiting their use. This decrease in performance largely stems from porosity laden parts, and asymmetric solidification-based microstructures. Solid-state additive manufacturing techniques bypass these flaws, using deformation and diffusion phenomena to bond material together layer by layer. Among these techniques, Additive Friction Stir Deposition (AFSD), stands out as unique for its freeform nature, and thermomechanical conditions during material processing. Leveraging its solid-state behavior, optimized microstructures produced by AFSD can reach performance levels near, at, or even above traditionally prepared metals. A strong understanding of the material conditions during AFSD and the phenomena responsible for microstructure evolution. Here we discuss two works aimed at improving the state of knowledge surrounding AFSD, promoting future microstructure optimization. First, a parametric study is performed, finding a wide array of producible microstructures across two material systems. In the second work, a stop-action type experiment is employed to observe the dynamic microstructure evolution across the AFSD material flow pathway, finding specific thermomechanical regimes that occur within. Finally, multiple conventional alloy systems are discussed as their microstructure evolution pertains to AFSD, as well as some more unique systems previously limited to small lab scale techniques, but now producible in bulk due to the additive nature of AFSD.<br>Doctor of Philosophy<br>The microstructure of a material describes the atomic behavior at multiple length scales. In metals this microstructure generally revolves around the behavior of millions of individual crystals of metal combined to form the bulk material. The state and behavior of these crystals and the atoms that make them up influence the strength and usability of the material and can be observed using various high fidelity characterization techniques. In metal additive manufacturing (i.e. 3D printing) the microstructure experiences rapid and severe changes which can alter the final properties of the material, typical to a detrimental effect. Given the other benefits of additive manufacturing such as reduced costs and complex part creation, there is desire to predict and control the microstructure evolution to maximize the usability of printed material. Here, the microstructure evolution in a solid-state metal additive manufacturing, Additive Friction Stir Deposition (AFSD), is investigated for different metal material systems. The solid-state nature of AFSD means no melting of the metal occurs during processing, with deformation forcing material together layer by layer. The conditions experienced by the material during printing are in a thermomechanical regime, with both heating and deformation applied, akin to common blacksmithing. In this work specific microstructure evolution phenomena are discussed for multiple materials, highlighting how AFSD processing can be adjusted to change the resulting microstructure and properties. Additionally, specific AFSD process interactions are studied and described to provide better insight into cumulative microstructure evolution throughout the process. This work provides the groundwork for investigating microstructure evolution in AFSD, as well as evidence and results for a number of popular metal systems.
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Borille, Anderson Vicente. "Decision support method to apply Additive Manufacturing Technologies for plastic components in the aircraft industry." Instituto Tecnológico de Aeronáutica, 2009. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1916.
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Additive Manufacturing Technologies (AMT) are a collection of manufacturing processes driven by CAD data to produce physical models and parts by means of additive techniques. They are based on a layer-by-layer material consolidation process instead of the traditional methods. Due to machine and material developments, such processes may be used to produce final products, not only prototypes. The use of AMT to produce end-use parts is known as Rapid Manufacturing (RM). The main advantages AMT are related to the ability to build geometrically complex shapes without tooling and with high process automation. At small lot sizes, such as with customized products, traditional manufacturing technologies become expensive due to high costs of required tooling. Small lot sizes and complex shaped parts are typical features encountered in the aircraft industry. Nowadays, two Additive Manufacturing Technologies are able to process plastic materials which comply flammability requirements: Fused Deposition Modeling (FDM) and Selective Laser Sintering (SLS). The main objective of this work is to propose a decision support method based on processes technological information concerning Rapid Manufacturing of plastic parts for aircraft cabin interiors. Thus, both FDM and SLS process are compared regarding their functionality (software interface), tensile strength, accuracy and part definition, surface roughness, build time and costs. The analyzed materials are the Polyamide with flame retardant (PA2210FR) additives and the Polyphenylsulfone (PPSF) for SLS and FDM process respectively. These materials were selected because they were the available flame retardant materials for AMT as the beginning of this work. A method is proposed to consider AMT possible advantages and restrictions when considering the manufacturing process. It is proposed that design modifications to improve part';s functionality or performance may be manufactured by AMT. Further, the method proposes the decision procedure to evaluate quality, production time and cost. The author illustrates the method with examples on the selection of manufacturing technology to produce a customized decoration part and an air duct. Typical costs and manufacturing time of injection molding processes were also compared and analyzed with the proposed method. It is possible to define the break-even point, when conventional processes become preferred then AMT.
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Schaefer, Carolyn (Carolyn E. ). "Irradiated recycled plastic as a concrete additive for improved chemo-mechanical properties in hardened cement pastes." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/114051.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Page 37 blank. Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 33-36).<br>Portland cement based concrete production contributes heavily to greenhouse gas emissions. Thus a need exists for the development of durable and sustainable concrete with a lower carbon footprint. This can be achieved when Portland cement is partially replaced with another material without compromising the concrete's strength. The use of waste plastics in concrete has been explored as a means of improving concrete's mechanical properties while also providing an efficient way to both re-purpose waste plastic and partially displace cement for the purpose of reducing carbon emissions. This replacement, however, typically comes with a sacrifice of compressive strength. This work discusses the design for and progress toward a high-strength concrete with a dense cementious matrix that contains an irradiated plastic additive. Cement samples containing various combinations of cement binder and plastic content were prepared; compressive strength tests showed that for all cement binder types, the addition of high dose irradiated plastic resulted in increased compressive strength as compared to the strengths achieved by samples with regular, non-irradiated plastic. This suggests that irradiating plastic at a high dose is a viable potential solution for gaining some of the strength back that is lost when plastic is added to concrete. To assess the internal structure of the samples and gain some insight into what aspects of their chemical compositions' contributed to the observed strength differences, a microstructural analysis -- consisting of XRD, SEM, and X-ray microtomography -- was performed. XRD analysis showed that various differences in C-S-H and C-A-S-H phase formation from the addition of both irradiated plastic and mineral additives helped to form high-density phases that contributed to higher relative strengths. BSE analysis showed that an increased alumina content among fly ash samples helped to form the high-density phases that contributed to higher relative strength among the fly ash samples, as evidenced through a ternary phase diagram. X-ray microtomography showed that the addition of high dose irradiated plastic consistently contributed to a decrease in segmented porosity, indicating that irradiated plastic may have acted as a pore-blocking agent. The results presented clearly show the benefit of using irradiated plastic as a concrete additive for improved compressive strength. By partially replacing Portland cement with a repurposed waste material, this design, when scaled to the level of mass concrete production, could contribute to reduced carbon emissions and provide a long-term solution for waste plastic storage.<br>by Carolyn Schaefer.<br>S.B.
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Kim, Sangho. "Comparative Life Cycle Assessments of Conventional Products and 3D-Printed Wood-Plastic Composite Alternatives." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-287737.
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As additive manufacturing gains market potential as a mainstream process in various sectors of industry, there is a growing need for addressing environmental aspects of this technology and the materials associated with it. In this master thesis, comparative life cycle assessments (LCAs) from cradle to grave between the conventional products and 3D-printed alternatives made of wood-plastic composite (WPC) were conducted based on the ISO 14044:2006 standard. Environmental impacts of each product were quantified for 10 impact categories. The goal of the LCAs was to determine whether the use of the 3D-printed WPC products may suggest a sustainable alternative to the conventional ones. This master thesis presents three case studies in which comparative LCAs were carried out. The first two case studies are about storage compartments for trucks from Scania, and the third one is about ceiling boards from Veidekke. The results showed that, in all case studies, the 3D-printed WPC alternatives would have smaller environmental impacts compared with the conventional products. The most significant difference was observed in the first two case studies because of the light- weighting effect. The alternatives showed 51%, 68% and 13% lower global warming potential (GWP) than the conventional products in each case study, respectively. However, the results of the cradle-to-gate LCAs suggested that the 3D-printed WPC alternative might cause greater environmental impact than the conventional products regarding some impact categories. Therefore, in the LCA context, the 3D-printed WPC alternatives would be much more beneficial to the environment compared with the conventional products, but theenvironmental benefits might be insignificant from the manufacturer’s perspective.<br>Eftersom additive tillverkningsteknik ökar marknadspotentialen som en vanlig process inom olika industrisektorer, finns det ett växande behov av att ta itu med miljöaspekterna av denna teknik och de material som är associerade med den. I detta examensarbete avhandling genomfördes jämförande livscykelanalys (LCA) från vagga till grav mellan de konventionella produkterna och 3D-printade alternativ av träplastkomposit (WPC) baserat på ISO 14044: 2006-standarden. Miljöpåverkan av varje produkt kvantifierades för 10 miljöeffekter. Målet med LCA var att avgöra om användningen av de 3D-printade WPC-produkterna kan vara ett hållbart alternativ till de konventionella. Denna avhandling presenterar tre fallstudier där jämförande LCA utfördes. De två första fallstudierna handlar om förvaringsutrymmen för lastbilar från Scania, och den tredje om takskivor från Veidekke. Resultaten visade att de 3D- printade WPC- alternativen i alla fallstudier skulle ha mindre miljöpåverkan jämfört med konventionella produkter. Den mest signifikanta skillnaden observerades i de två första fallstudierna på grund av den lägre vikte viktningseffekten. Alternativen visade 51%, 68% och 13% lägre global uppvärmningspotential (GWP) än de konventionella produkterna i respektive fallstudie. Emellertid föreslog resultaten av vaggan-till-grind-LCA att det 3D-printade WPC-alternativet kan orsaka större miljöpåverkan än de konventionella produkterna avseende vissa miljöeffekter. Därför, i LCA-sammanhang, skulle de 3D-printade WPC-alternativen vara mycket mer fördelaktiga för miljön jämfört med konventionella produkter, men miljöfördelarna kan vara obetydliga ur tillverkarens perspektiv.
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Fumelli, Giovanni. "Valutazione primaria degli impatti ambientali nel processo Arburg Plastic Freeforming." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20773/.
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Il crescente impiego di tecnologie inerenti al campo dell’additive manufacturing nel settore della produzione industriale necessita di testimonianze scientifiche su quelli che possono essere gli impatti ambientali connessi all’utilizzo di questo tipo di processi.
Questo documento si propone di analizzare attraverso lo strumento di Life Cycle Assessment (LCA) la tecnologia additiva Arburg Plastic Freeforming (APF) con un approccio del tipo “Craddle to Gate”. Tale studio vuole fornire un modello di riferimento in grado di valutare gli impatti ambientali legati ad una lavorazione additiva che fonda i suoi meccanismi sulle dinamiche dello stampaggio ad iniezione. Il modello proposto va interpretato come uno strumento di supporto per le fasi di progettazione di un nuovo processo/prodotto, indirizzando le scelte operative nella direzione della sostenibilità.
Il sistema viene mappato nel suo insieme in funzione di tutte le fasi connesse al ciclo di vita del prodotto. L'unità funzionale rispetto cui rapportare gli impatti ambientali è l’oggetto costruito attraverso lavorazione additiva: per quantificare efficacemente gli impatti, lo studio introduce come parametri di allocazione la massa del prodotto da realizzare ed il tempo di costruzione. Il modello è stato applicato coerentemente alla fabbricazione di un oggetto, presentando gli impatti ambientali attraverso due step procedurali: visualizzazione dei MidPoint (MP) ed EndPoint (EP), calcolati mediante ReCiPe v.1.1 in una prospettiva gerarchica. Vengono poi riportati i risultati ottenuti rispetto i quali è possibile individuare i contributi maggiormente influenti del processo in termini ambientali. Vengono proposti quelli che sono i parametri maggiormente impattanti della lavorazione. Sono presentate inoltre le dinamiche relative ad analisi comparative che modellano il confronto tra due materiali costitutivi sottoposti alla stessa lavorazione, di cui se ne riportano i risultati.
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Krehl, Valentin. "PLASTIC ADDITIVE MANUFACTURING AND ITS POTENTIAL EFFECTS ON A SUPPLY CHAIN : A case study concerning selection of beneficial parts for additive manufacturing through utilizing a methodological part evaluation framework." Thesis, KTH, Industriell produktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226329.
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Recently additive manufacturing (AM) is rapidly growing and evolving due to the advancements made in speed, quality, resolution and performance. Consequently, AM is starting to become, beyond prototyping, increasingly important for the manufacturing of end-use parts. Several successful case studies are reported and companies are starting to investigate in the opportunities of using AM for production processes and supply chain integrations. The purpose of this research is to evaluate the potential of using AM for manufacturing plastic end-use parts in a supply chain. Different AM technologies for plastic manufacturing are described and the main advantages and challenges are identified. Based on the company’s plastic part scope, a methodical framework for assessing parts regarding their AM suitability is established, in order to research the potential benefits of an AM implementation. The framework contains a methodical preselection and scoring process utilizing a top-down approach and an analytical hierarchical process (AHP), followed by a technical and economic assessment of the promising parts. In the research, only the existing design is taken into account: the same part, designed for conventional manufacturing technologies, is manufactured by AM without changes in geometry. Both cases, in-house manufacturing and purchasing from a service provider, were investigated with the employment of a cost model for FDM technology and a request for quotation from a general AM service provider. Both cases are compared to each other and the current conventional manufacturing technology. It was found that, currently, utilizing an AM service provider is more beneficial for the company, due to the low number of parts that could be currently produced with AM. Hereby the lead time for AM profitable parts could be significantly reduced. Using AM, a centralized production with one AM service supplier is clearly seen as the preferable supply chain configuration in the case of the company. The research provides guidance for the evaluation of part suitability concerning AM production of end-use plastic parts and contributes to the research concerning AM implementation in a supply chain in general and the aim of the company to acquire valuable AM knowhow in particular.<br>På sista tiden växer Additive Manufacturing (AM) snabbt och framläggar på grund av de framsteg som gjorts i hastighet, kvalitet, upplösning och performans. Följaktligen börjar AM, förutom prototypning, att blir viktigare för tillverkning av användningsdelar. Flera framgångsrika fallstudier rapporteras och företagen börjar undersöka möjligheterna att använda AM för produktionsprocesser och integrering pa supply chain. Ändamål med denna forskning är att utvärdera potentialen att använda AM för tillverkning av plastdetaljer för slutanvändning i en supply chain. Olika AM-tekniker för plasttillverkning beskrivs och de viktigaste fördelarna och utmaningarna identifieras. På grundval av företagets plast delar omfång etableras en metodisk ram för bedömning av delar om deras AM-lämplighet för att undersöka de potentiella fördelarna med en AM implementering. Ramverket innehåller en metodisk förhandsval och poängprocess som utnyttjar en top-down-strategi och en analytisk hierarkisk process (AHP), följt av en teknisk och ekonomisk bedömning av de lovande delarna. I undersökningen beaktas endast den ekonomiska synvinkel: samma del, konstruerad för konventionell tillverkningsteknik, tillverkas av AM utan ändringar i geometri. Båda fallen, egen tillverkning och inköp från en tjänsteleverantör, undersöktes med anställning av en kostnadsmodell för FDM-teknik och en offertförfrågan från en allmän AM-tjänsteleverantör. Båda fallen jämförs med varandra och den nuvarande konventionella tillverkningstekniken. Det konstaterades att det för närvarande är en AM-tjänsteleverantör som är mer fördelaktig för företaget på grund av det låga antal delar som kan för närvarande produceras med AM. Härav kan ledtiden för AM-lönsamma delar minskas betydligt. Med AM används en centraliserad produktion med en AM-tjänsteleverantör tydligt som den föredragna leveranskedjekonfigurationen när det gäller företaget. Forskningen ger vägledning för utvärdering av delkompatibilitet avseende AM-produktion av plastdetaljer för slutanvändning och bidrar till forskningen om AM-genomförande i en supply chain i allmänhet och syftet med företaget att förvärva värdefullt AM-knowhow i synnerhet.
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Ting, Huang, and Nordqvist Daniel. "Design and manufacturing of SLM printed tooling for plastic injection molding." Thesis, Jönköping University, Tekniska Högskolan, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-54170.
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The thesis work is to show that the use of SLM (Additive Manufacturing) compared with the traditional process to make injection molds will have advantages in design, especially in waterways. This thesis work gives seven different versions of design applied to the SLM method to analyze and compare them in Solidworks® and Moldflow® to figure out what design is suitable for the SLM method. Through analysis of different versions, the finding of this thesis work is that the conformal waterway of design and lighter but stead structure in the SLM method causes the SLM molds' cooling performance to be almost 15% better than the conventional way and shorten the production time by 18% per product. Based on the advantages of the SLM method in cooling system design and structure optimization, the company can use the SLM method in the production process to improve economic and environmental benefits.
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Stellmar, Justin. "Predicting the Deformation of 3D Printed ABS Plastic Using Machine Learning Regressions." Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1587462911261523.
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Edmonds, Hannah. "Interlaminar bonding in ultrasonic consolidation." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10999.
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Ultrasonic Consolidation (UC) is a solid state additive manufacturing process which fabricates three-dimensional objects by ultrasonically joining metal foils together, layer-bylayer, to form a solid part. A wide range of materials can be used to fabricate parts by UC and products with complex internal geometry can be generated by shaping the crosssection throughout the build using Computer Numerically Controlled (CNC) milling. As a result of its ability to embed various secondary materials and fibres in metal matrices, UC has emerged as a potential method of fabricating multi-functional materials and structures.
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Sojiphan, Kittichai. "Effects of Very High Power Ultrasonic Additive Manufacturing Process Parameters on Hardness, Microstructure, and Texture of Aluminum 3003-H18 Alloy." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1418667794.
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Bäckman, Tobias. "Utredning om konstruktion och beräkning för additiv tillverkning - Markforged." Thesis, Mälardalens högskola, Innovation och produktrealisering, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-40172.
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The following thesis work was performed by Tobias Bäckman between 2018-01-15 – 2018-06-01 on behalf of Deva Mecaneyes. Deva Mecaneyes had identified a need and a possible application area for additive manufacturing based on the Markforged Mark Two 3D-printer which they had purchased. However, many question marks remained regarding how the materials from the printer would behave. How to design against this manufacturing method and which applications that could be beneficial for the company. At the start of the project it was identified that Deva Mecaneyes main limitations for not implementing 3D-manufacturing more extensive in their product development process was partly the lack of experience of additive manufacturing methods but mainly due to the lack of reliable material data for the printed parts. Based on this, three research questions were formulated. These research questions discuss how to replace traditional manufacturing methods, which material relationships are possible to identify, and which factors should be considered when designing against additive manufacturing. The bulk of the work thus consisted of producing material data for materials that are compatible with Markforged mark Two. This was done based on ASTM standards that treat tensile tests, bending tests and fatigue tests. Two already existing products from Deva Mecaneyes in the field of lifting gear for manufacturing industries were selected with the purpose to redesign these products to be manufactured with the Mark Two 3D-printer instead. In this way, an alternative way for these applications could be showed by replacing the traditional manufacturing methods with additive manufacturing methods. The reconstructed lifting gear was also manufactured to be verified against the produced material data but also to demonstrate improvement or deterioration against the existing lifting gear. The measurable goals for the project were to prove cost and time reduction by at least 50% by replacing the traditional manufacturing methods with additive manufacturing methods while maintaining the same reliability. The result demonstrated two redesigned lifting gears with many improvement areas. A great result that stood out was a cost reduction of approximately 80% and 90% respectively. Several material relationships have been identified during the work and new experiences regarding printed details have arisen. The author believes that the work, with addition to the accomplished goals, has laid a good ground to begin to understand the materials more and more and thus a good beginning to obtaining a reability from 3D-printed details. Which is a decisive factor to begin replacing the traditional manufacturing methods.<br>Följande examensarbete är utfört av Tobias Bäckman mellan 2018-01-15 – 2018-06-01 på uppdrag av företaget Deva Mecaneyes. Deva Mecaneyes hade identifierat ett behov och ett möjligt användningsområde för additiv tillverkning baserat på en 3D-skrivare av modellen Markforged mark Two som de köpt in. Dock kvarstod det många frågetecken hur materialen i de utskrivna detaljerna beter sig, hur man skall konstruera mot denna tillverkningsmetod samt vilka tillämpningsområden som skulle kunna vara fördelaktiga. Vid uppstart av projektet identifierades de största begränsningarna till varför Deva Mecaneys inte implementerar 3D- utskrifter mer omfattande i deras konstruktionsarbete som delvis den bristande erfarenheten av additiva tillverkningsmetoder, men främst på grund av avsaknaden av trovärdig materialdata och beräkningsunderlag att tillämpa för fysiska 3D-utskrivna detaljer. Utifrån detta formulerades tre stycken forskningsfrågor. Dessa forskningsfrågor behandlar hur man skulle kunna ersätta traditionella tillverkningsmetoder, vilka materialsamband som är möjliga att identifiera samt vilka faktorer som bör tas hänsyn till vid konstruktion mot additiva tillverkningsmetoder.Huvuddelen av arbetet har därmed bestått av att producera materialdata för materialen som är kompatibla med Markforged Mark Two. Detta har skett baserat på ASTM-standarder som behandlar dragprover, böjprover och utmattningsprover.Två befintliga produkter från Deva Mecaneyes inom området lyftredskap valdes sedan ut för att omdesignas mot additiva tillverkningsmetoder. På så vis redovisas en alternativ väg att gå genom att ersätta de traditionella tillverkningsmetoderna med additiva tillverkningsmetoder. De omkonstruerade lyftredskapen tillverkades även för att dels verifieras mot den framtagna materialdatan men även för att redogöra förbättring alternativt försämring mot de befintliga lyftredskapen.De mätbara målen för arbetet var att kunna påvisa kostnads och tidsreducering med 50% genom att byta ut de traditionella tillverkningsmetoderna mot additiva tillverkningsmetoder. Resultatet påvisade två omkonstruerade lyftredskap med många förbättringsområden. Där framförallt en kostnadsreducering på cirka 80% respektive 90% identifierades.Under arbetets gång har ett antal materialsamband kunnat identifieras och nya erfarenheter angående utskrivna detaljer från Markforged Mark Two har uppstått. Författaren anser att arbetet, utöver de uppfyllda målen, har lagt en god grund till att börja förstå materialen mer och mer och därmed en god början till att börja erhålla en tillförlitlighet hos 3D-utskrivna detaljer som är en avgörande faktor till att börja ersätta vissa av de traditionella tillverkningsmetoderna.
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Sreedhar, Aldric, and C. L. Kaushik Gupta. "Pre-study on the use of additive manufacturing to produce low volume complex parts and its environmental sustainability." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-52800.
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With the rapid increase in demand for more high-value customized products and a more sustainable approach to manufacturing, companies are focusing on being more flexible while also trying to minimize environmental impact. As it is not possible to meet these current demands using traditional manufacturing techniques, manufacturing industries are searching for better manufacturing alternatives to address these issues in order to stay competitive. In this thesis, the two issues of manufacturing complex, low volume parts and environmental sustainability were investigated with the use of the additive manufacturing (AM) technology and possible improvements/recommendations were suggested. The conclusions drawn suggested that AM could be used to produce complex parts more efficiently and also proved to be a more sustainable alternative with decreased energy and resource consumption when compared to traditional methods.
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Hermabessiere, Ludovic. "Les microplastiques et leurs additifs dans les produits de la pêche : développements méthodologiques et prévalence." Thesis, Littoral, 2018. http://www.theses.fr/2018DUNK0492/document.
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L'augmentation de la production de matière plastique depuis les années 1950 combinée à une mauvaise gestion des déchets plastiques ainsi qu'aux mauvais comportements des citoyens conduit à la contamination des écosystèmes terrestres comme marins. L'ingestion par des organismes marins de particules plastiques mesurant moins de 5 mm, appelées microplastiques, a été décrite. L'objectif de ces travaux de thèse était d'évaluer le danger "microplastique" pour le consommateur de produits de la pêche. Afin de répondre à cet objectif, la sélection et la caractérisation d'une méthode permettant de digérer les tissus des produits de la pêche a été. En parallèle, une méthode de Pyrolyse-GC/MS a été optimisée afin d'identifier les microplastiques les plus petits possibles. Ses limites d'applications ont été calculées puis la méthode a été appliquée sur des microplastiques provenant de différents produits de la pêche. Ces deux méthodes ont été appliquées dans la recherche de microplastiques dans deux espèces de bivalves et trois espèces de poissons. Pour les bivalves, la contamination aux microplastiques était comprise entre 0.15 et 0.74 MP/g de chair humide alors que pour les poissons la contamination était assez faible : 0,01 MP/g de tractus gastro-intestinal et 0,001 MP/g de filet. Pour finir, une étude exploratoire de la lixiviation d'un additif plastique en utilisant un modèle de digestion in vitro a été entreprise. Globalement, ces travaux de thèse permettent de proposer des voies d'harmonisation des méthodes pour l'étude des microplastiques dans les produits de la pêche pour, in fine, évaluer le danger pour le consommateur<br>Increase in plastic production since the 1950's in combination with plastic waste mismanagement lead to the presence of plastic particle in terrestrial and marine environment. Plastic particles measuring less than 5 mm, called microplastics, are ingested by a wide range of organisms. The goal of this PhD thesis was to evaluate the microplastic hazard for seafood consumers. firstly, method for digesting seafood tissue without degrading plastic polymer was selected and applications limits were determined for digestion of fish digestive tracts. Concurrently, a Pyrolysis-GC/MS method was optimized, limit of detection were determined and this method was applied on environmental samples. Both methods were used to study microplastics contamination in bivalve and fish species used for human consumption. Bivalve contamination was between 0.15 and 0.74 MP/g of tissue wet weight whereas contaminations in fish were low. Indeed, digestive tracts were contaminated by in mean 0.01 MP/g of tissue wet weight and muscles were contaminated by in mean 0.001 MP/g of tissue wet weight. Lately, leaching of a plastic additive was studied using an in vitro enzymatic model of digestion. However, such phenomenon was not highlighted. Overall, these results will help to standardize the study of microplastics in seafood products
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Ogbobe, Okoro. "Dispersion of additive masterbatches in polyolefin plastics." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/15384.
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There has been a growing trend in recent years for polymer product manufacturers to use natural polymer and additive masterbatches instead of premixed compounds. For both polymer converters and polymer manufacturers, masterbatching makes economic sense. For the converter, the advantage is in the ability to buy and store in bulk a small number of base polymers which may be modified according to the dictates of the order book. This prevents the need to maintain an inventory of a large number of special compounds. Masterbatch base is very often low molecular weight polyethylene or some suitable low molecular weight compound. They are usually used with a wide range of polymer compounds. Manufacturers assume good additive dispersion in the products with use of masterbatch. This study investigates the quality of dispersion in masterbatches and the extent they can be used with varying polyolefin polymers. Also investigated is how additive particles are transferred from the masterbatch to another polymer during mixing and any morphological features that might relate to the degree of dispersion. A quantitative dispersion procedure in polyolefin products is also sought. X-ray microradiography, light microscopy and ultraviolet microscopy have enabled pigment and ultraviolet absorber dispersion in masterbatches and products to be studied. Pigment dispersion in low density polyethylene masterbatch is almost invariably bad. Iron oxide particularly was found to be the most poorly dispersed compared to other inorganics such as zinc sulphide, titanium dioxide and cadmium sulphide. On the other hand, the distribution of Cyasorb 531 in LDPE masterbatch is uniform. The degree of dispersion of UV absorber in polyethylene products depends on the difference between the melt flow index between the masterbatch base and the base polymer. Simulated sunlight exposure experiments have shown that increased absorber distribution significantly increases photostability of a high MFI HDPE/LDPE UV masterbatch blend. A semi-automatic procedure for quantifying pigment dispersion in polyolefin products has been developed. It involves a motorised stage scanning of a microtomed section of a polyolefin product with measurements being made with a photometer operating in a dark-field illumination and interfaced to a microcomputer. The procedure has enabled the point of significant agglomeration as well as the effect of shear rate and temperature on degree of dispersion in extruded products to be determined.
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Engkvist, Gustav. "Investigation of microstructure and mechanical properties of 3D printed Nylon." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-66304.
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This thesis presents a multiscale investigation and characterization of additive manufactured Polyamide material using fused deposition modelling technique. Manufacturing was performed using Markforgeds – Mark one 3D printer. A multiscale investigation dedicated to minimizing the effect of shape distortion during 3D printing are presented, focusing on both molecular alignment in microstructure and implementing internal structures in mesostructure. Characterization on samples investigating microstructure was performed with coefficient of linear thermal expansion measurement and 3-point bending experiment. Different samples with varying infill patterns are tested and results indicates an isotropic behaviour through the manufactured samples and implies no molecular alignment due to printing pattern. In meso-structure, an implemented internal pattern is investigated. All samples are measured with 3D scanning equipment to localize and measure the magnitude of shape distortion. Attempts to find relationships in shape distortion and porosity between the samples resulted in no observed trends. Compressive experiments where performed on samples in axial- and transverse directions resulting in anisotropic behaviour. The largest compressive stiffness is recorded in axial direction reaching 0,33 GPa. The study is done in collaboration with Swerea SICOMP and Luleå University of Technology.
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Bardi, Marcelo Augusto Gonçalves. "Avaliação do impacto ambiental gerado por tintas gráficas curadas por radiação ultravioleta ou feixe de elétrons em materiais para embalagens plásticas convencionais ou biodegradáveis pós-consumo." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-17032015-101014/.
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O alto nível de poluição gerado pelo descarte inadequado de materiais poliméricos vem motivando pesquisas por sistemas e técnicas ambientalmente corretos, tais como a aplicação de polímeros biodegradáveis e a substituição dos sistemas de pintura à base de solventes por aqueles com alto teor de sólidos, à base de água ou, praticamente isentos de compostos orgânicos voláteis (VOCs) e curáveis por radiação. Todavia, os revestimentos poliméricos curados são insolúveis e infusíveis, aumentando o grau de complexidade do seu reprocessamento, da sua reciclagem e da degradação desejável. Assim, este trabalho apresenta, como objeto de contribuição científica, a obtenção de tintas modificadas com agentes pró-degradantes, curadas por reações químicas induzidas por radiação ultravioleta ou feixe de elétrons (UV/EB), para impressão em embalagens plásticas, biodegradáveis ou não, para produtos de baixa vida útil. Foram estudadas combinações de seis revestimentos, sendo um verniz não pigmentado e cinco tintas nas cores amarela, azul, branca, preta e vermelha; três agentes pró-degradantes (estearatos de cobalto, cério e manganês), cinco substratos poliméricos (Ecobras®, polietileno de baixa densidade e suas respectivas modificações com os agentes pró-degradantes). Os revestimentos foram aplicados nos substratos e curados por radiação UV ou EB, resultando em 180 amostras. Estes materiais foram, então, expostos ao envelhecimento acelerado em câmara tipo QUV e à compostagem em ambiente natural. De modo a se compreender o efeito dos revestimentos poliméricos no processo de degradação das amostras, foram selecionadas aquelas com valores extremos de grau de conversão, a saber: amarela e preta, as quais foram expostas à compostagem em ambiente controlado via respirometria, reduzindo de 180 para 16 o número de amostras. O composto orgânico gerado pelo processo de biodegradação foi analisado por testes de ecotoxicidade. Foi observado que a camada de revestimento atua como barreira que inibe a degradação do plástico quando exposto às intempéries. Adicionalmente, constatou-se que quanto maior o grau de conversão das formulações pigmentadas pastosas em sólidas durante a cura por radiação ultravioleta, maior foi sua mineralização em ambiente de compostagem. As amostras curadas por EB apresentaram menor taxa de biodegradação do que as curadas por UV. Isso se deu em virtude da rede de ligações cruzadas entre as cadeias poliméticas, geradas na cura por EB. A adição dos agentes pró-degradantes promoveu uma aceleração no processo de degradação, ocasionando, inclusive, a migração do íon metálico para o meio, porém sem afetar a qualidade do meio de compostagem.<br>The high level of pollution generated by the inadequate disposal of polymeric materials has motivated the search for environmentally friendly systems and techniques such as the application of biodegradable polymers and the replacement of the solvent-based paint systems by those with high solids content, based water or cured by radiation, practically free of volatile organic compounds. However, the cured polymer coatings are neither soluble nor molten, increasing the complexity of the reprocessing, recycling and degradation. Thus, this work aimed to develop print inks modified with pro-degrading agents, cured by ultraviolet radiation or electron beam, for printing or decoration in plastic packaging products of short lifetime, which are biodegradable or not. Six coatings (varnish and inks in five colors: yellow, blue, white, black and red), three pro-degrading agents (cobalt stearate, cerium stearate and manganese stearate), five polymeric substrates (Ecobras®, low density polyethylene and its respective modifications with pro-degrading agents). The coatings were applied to the substrates and cured by ultraviolet radiation or electron beam, resulting in 180 samples. These materials were then exposed to accelerated aging chamber, type \"QUV\", and composting in natural environment. In order to assess the effects of the polymer coatings on the degradation process of the specimens, only the yellow and black samples were exposed to a controlled composting environment via respirometry, reducing to 16 the number of samples. The organic compound generated by the biodegradation process was analyzed by the ecotoxicity tests. It was observed that the coating layer acted as a barrier that inhibits degradation of the plastic when exposed to weathering. The addition of pro-degrading agents promoted acceleration in the degradation process, promoting the migration of the metal ion to the medium without affecting the final quality of the organic compost.
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Börno, Fabian. "Analyse von Kunststoffadditiven mittels Laserablation gekoppelt mit induktiv gekoppelter Plasma Massenspektrometrie." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17679.
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Die Laserablation gekoppelt mit der Massenspektrometrie mit induktiv gekoppeltem Plasma ist eine vielversprechende direkte Feststofftechnik, die sich jedoch bei der Analyse von Kunststoffen wegen des Mangels an matrixangepassten zertifizierten Referenzmaterialien nicht durchsetzen konnte. Vorherige Arbeiten belegen polymerabhängige Abtragsraten. Das oft als interner Standard verwendete Intensitätssignal des Kohlenstoffisotopes 13C zur Korrektur dieser Unterschiede wird in der Literatur kritisch diskutiert. In dieser Arbeit als ein Teil des BMBF-geförderten MaxLaP-Projektes wurden matrixangepasste Standards auf Polyethylen- und Acrylnitril-Butadien-Styrolbasis entwickelt. In diese Standards wurden Br, Cd, Cu, Cr, Fe, Sb in organischer und anorganischer Form ihrer Verbindungen mittels Extrusion eingearbeitet. Die quantitative Zusammensetzung der Materialien wurde mittels ETV-ICP-OES, DC-arc-OES, RFA und ICP-MS nach Mikrowellendruckaufschluss überprüft. Die Verfahren wurden für die Kunststoffanalyse optimiert. Die mikroskopische Homogenität der Einarbeitung wurde mittels µ-SYRFA und LA-ICP-MS untersucht. Zur Untersuchung der Matrixeffekte während der LA-ICP-MS und der matrixunabhängigen Kalibrierung für Kunststoffe wurden der Einfluss der chemischen Verbindung der Additive, die Größe, der bei der Laserablation gebildeten Partikel und die Art des Kunststoffes auf die Laserablation analysiert. Die Korrektur des verschiedenen Materialabtrages über die Verwendung des 13C-Signals konnte für 21 verschiedene Kunststoffe erfolgreich durchgeführt werden. Allerdings zeigen die zugesetzten Additive ein nicht identisches Verhalten hinsichtlich Transport und Ionisierung. Weitere Ergebnisse belegen eine Anreicherung der Additive in verschiedenen Partikelgrößen sowie eine deutlich unterschiedliche Partikelbildung bei Ablationen von verschiedenen polymeren Matrices, was zu einer verstärkten Elementfraktionierung bei einer nicht matrixangepassten Kalibrierung führt.<br>Laser ablation coupled to a mass spectrometer with inductively coupled plasma (LA-ICP-MS) is a promising direct solid sampling technique. Due to the lack of matrix matched standard materials laser ablation is not well established in polymer analysis. In a recent study a polymer dependent interaction with the laser beam was reported, which resulted in a polymer depending ablation rate. The usage of the carbon-13-signal intensity as internal standard to correct these differences as commonly applied has been critically discussed in literature. In this work as part of a BMBF-supported MaxLaP-project (matrix effects during laser ablation of polymers) matrix matched standards based on polyethylene and acrylonitrile butadiene styrene were developed. In these materials Br, Cd, Cu, Cr, Fe and Sb were incorporated as organic and inorganic compounds through extrusion. Quantitative composition of the materials was determined by ETV-ICP-OES, DC-arc-OES, XRF and ICP-MS after high pressure microwave digestion. Analytical methods were optimized for trace analysis in plastic matrices. Microscopic homogeneity was examined by µ-SyXRF as well as LA-ICP-MS. In order to investigate the matrix effects and to determine the possibility of a matrix independent calibration for plastic materials, the influence of the chemical form of the additives, size of the formed particles and the type of the plastic on the LA-ICP-MS measurements were analyzed. The correction of the material uptake by the carbon-13-signal was successfully applied for 21 different types of plastic. However, different incorporated additives show a different transport and ionization behavior. Furthermore, our results confirm a different enrichment of the additives depending on particle size and a significantly different particle formation for different types of plastic, which leads to a more pronounced elemental fractionation by not using a matrix matched calibration.
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HoaÌ€ng, Eric MiÌnh. "Additives interactions in the thermo-oxidative degradation of metallocene polyethylene." Thesis, Manchester Metropolitan University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289422.
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During the 1990's the development of metallocene catalysts has made a dramatic impact on the polyethylene industry. A large amount of work can be found in the literature regarding the degradation and stabilisation of conventional polyethylenes. However, very few studies have been devoted to these novel metallocene polymers. The first part of this thesis deals with the thermo-oxidative degradation of various metallocene polyethylenes (mPE's) in the solid state (oven ageing at 90°C in air) and the melt state (via mastication in air in a Brabender® mixer). For each mPE, essentially one characteristic (melt index, molar mass distribution, density and ash content) was changed at a time. In the second part, the effect of different grades (animal versus vegetable) and types (calcium versus zinc stearates) of metallic stearates in combination with phenolic and phosphite antioxidants was investigated in the melt stabilisation of a standard metallocene LLDPE (mLLDPE). Finally, interactions between additives present in a typical stabiliser package used for film grade LLDPE were assessed in the stabilisation of the mLLDPE with help of a two-level factorial design of experiments. The response included melt flow protection and discolouration during processing, as well as long-term stability. Outstanding thermo-oxidative stability was exhibited for all the mPE's in the solid state. This remarkable oxidative stability was believed to be due to the presence of low concentrations of innocuous metal catalyst residues, as well as low initial vinyl unsaturation content and degree of branching. Furthermore, polymer density/crystallinity appeared to reduce the spreading rate of oxidation. In the case of thermo-oxidation in the melt state, the polymer melt viscosity appeared to govern the processing stability of the metallocene polymers. In the second part, it was found that the quality of the metal stearates, i.e., peroxide content, metal oxide and unsaturation, may affect the performance of the phenolic and phosphite antioxidants in the melt stabilisation of the mLLDPE. Finally, the statistical design of experiments proved to be a very useful tool for screening the effects of each additive and the possible interactions between additives present in the investigated stabiliser system.
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Armstrong, Kenneth Mark. "Catalytic synthesis of organophosphate plastics additives from white phosphorus." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2587.
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Triaryl phosphates were synthesized from white phosphorus and phenols in aerobic conditions and in the presence of iron catalysts and iodine. Full conversion to phosphates was achieved without the use of chlorine or chlorinated solvents, and the reactions do not produce acid waste. Triphenyl phosphate, tritolyl phosphate and tris(2,4-di-tert-butyl)phenyl phosphate were synthesized by this method with 100% conversion from P₄. Various iron(III) diketonates were used to catalyse the conversion. Mechanistic studies showed the reaction to proceed via the formation of phosphorus triiodide (PI₃), then diphenyl phosphoroiodidate (O=PI(OPh)₂) before the final formation of triphenyl phosphate (O=P(OPh)₃). The nucleophilic substitution of O=PI(OPh)₂ with phenol to form O=P(OPh)₃ was found to be the rate determining step. It was found that by modifying the reaction conditions the same catalytic systems could be used to synthesize triphenyl phosphite directly from P₄. Triphenyl phosphite was synthesized in selectivities of up to 60 %. The mechanism of these transformations was also elucidated. Independent syntheses of the intermediate in the reaction mechanism, O=P(OPh)₂I and its hydrolysis products diphenyl phosphate (O=P(OPh)₂OH) and tetraphenyl pyrophosphate ((O)P(OPh)₂-O-P(O)(OPh)₂) were developed from PI₃. The 2,4-di-tert-butyl phenol analogues of these compounds were also prepared. Bis-(2,4-di-tert-butylphenyl) phosphoroiodidate was then reacted with various alcohols to produce a series of mixed triorgano phosphates.
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Mulcahy, Ciara(Ciara Renee). "Analysis of patent data for flame-retardant plastics additives." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/131011.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020<br>Cataloged from the official PDF version of thesis.<br>Includes bibliographical references (pages 33-35).<br>Plastics are commercially produced by selecting a polymer resin and incorporating chemical additives to affect specific mechanical, chemical or aesthetic properties of the plastic products. The number of possible combinations of polymers and additives yields an enormous engineering space to meet the design requirements of the many applications of plastic materials. However, the broad scope of plastics science hinders both the invention of new plastics formulations and efforts to investigate potentially harmful polymer resins and plastic additives. In this thesis, a method of representing and analyzing the claims section of patents is presented and applied to a set of patents that refer to flame retardants. The claims section of a patent is presented as a graph, with individual claims as points and references between claims as lines connecting those points.<br>The chemical terms mentioned in the text of each of the claims were split into individual words or short sequences of words, called "tokens", by an existing materials tokenizer that had been trained on scientific journal articles. The term frequency - inverse document frequency (tf-idf) statistic for each token within each claim was computed, using the entire claims section of the individual patent to calculate the document frequency. Each claim was attributed the tokens that had tf-idf scores greater than the highest-scoring term shared with a claim to which that claim referred. By researcher inspection, this method served to extract relevant chemical terms, while omitting words that did not contribute to the chemical relevance of the claim or patent as a whole. A visualization of these labelled graphs of the claims was generated.<br>This reduced, graphical representation of materials patents could be implemented to aid in researcher review or computational tasks to survey for chemical components or resin-additive compatibilities. Such a representation of patent data could make the prioritization and review of commercial chemicals a more tractable task.<br>by Ciara Mulcahy.<br>S.B.<br>S.B. Massachusetts Institute of Technology, Department of Materials Science and Engineering
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Rodrigues, Mayza Loureiro Araújo. "Adição de resíduo de argamassas mistas na produção de tijolos modulares de solo-cimento." Universidade Federal de Goiás, 2008. http://repositorio.bc.ufg.br/tede/handle/tde/2859.
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Vigren, David. "Migration of Xenoestrogens from Plastic Food Containers during Cooking." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-43957.
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Xenoestrogens are compounds, foreign from the body, that can enter cells and interact with the estrogen receptors (ER) to produce an estrogenic response. Many additives used in plastics are compounds with estrogenic activity. Some of these additives are known to slowly leach from the plastics. When using plastic containers as lunchboxes for reheating or food storage, these additives can leach from the plastics and end up in the food. In this project, food simulates were cooked in six different thermoplastic containers, made of polypropylene, in an oven at 100 °C for 15 minutes. Three of the thermoplastic containers were lunchboxes marketed to be able to withstand cooking in a microwave. The other three were provisional lunchboxes made from various food storing containers originally made for refrigeration purposes. The estrogenic activity in the different samples was measured using an ER-CALUX in vitro assay. The results were measured in 17β-estradiol equivalent (Bio-EEQ) values in pg/ml. The purpose of this project was to investigate whether or not these plastic containers leach xenoestrogens that can be measured with an ER-CALUX assay, and compare the results with the results from other existing toxicological studies, and also to see if there is a difference in Bio-EEQ levels between the plastic containers made for microwave usage and those made for refrigerated purposes. The results from this project indicate that most of these plastic containers do leach estrogenic compounds that can be detected in the ER-CALUX, even the ones made for microwave usage. Fortunately, compared to other toxicological studies, the Bio-EEQ levels in these food samples cooked in plastic containers are low. However the potential adverse effects in prenatally exposed children cannot be ignored as other studies have shown that very low levels of xenoestrogens are enough to potentially cause a disturbance in the reproductive development and fertility.
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Issart, Ambre. "Potentiel d'antioxydants naturels pour la stabilisation de polymères pour emballages alimentaires et le développement de méthodes pour évaluer leur migration." Thesis, Pau, 2019. http://www.theses.fr/2019PAUU3019.
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Les emballages plastique sont tristement connus pour la pollution accrue qu’ils entrainent. Les effets directs sur l’homme sont principalement dus à la migration de composés depuis le plastique vers les aliments qu’il contient. Ces composés ont des origines diverses : additifs, impuretés, produits de dégradations, réactions non contrôlées… A défaut de savoir arrêter cette migration, nous avons choisi d’en tirer profit grâce à de nouveaux matériaux, appelés matériaux actifs. Ces derniers ont pour objectifs de prolonger la durée de vie des aliments grâce à une migration dite « positive ». L’utilisation d’additifs naturels pose cependant un problème lié à leur résistance à la température. La problématique est donc de trouver des additifs naturels résistant à la température de mise en œuvre des polymères, tout en les stabilisant. C’est dans ce contexte que mon sujet de thèse a été mis en place, au sein du projet Foodyplast (POCTEFA). La thèse se découpe en quatre parties. Un état de l’art est tout d’abord présenté. Le chapitre suivant détaille les différentes techniques utilisées pour la réalisation et la caractérisation de nos matériaux ainsi que le développement d’une nouvelle méthode basée sur la spectrométrie de masse (LESA-MS). Le troisième chapitre aborde en détail la mise en œuvre de nouveaux matériaux stabilisés par des additifs naturels ainsi que leurs caractérisations physico-chimiques. Nous avons prouvé que l’utilisation conjointe de ces additifs (alpha-tocopherol/acide ascorbique et alpha-tocopherol/tannins) permet d’accroitre significativement l’effet de stabilisation sur la matrice polymère (innovation brevetée). Ces matériaux ont également montré être recyclable jusqu’à 9 fois sans dégradations. Enfin, le dernier chapitre reprend la nouvelle méthode du LESAMS, développée au chapitre 2, pour l’appliquer à la caractérisation de nos matériaux. Cette méthode est comparée à celle de la norme européenne en vigueur et ouvre de réelles perspectives d’analyses performantes dans les polymères pour différentes applications<br>Plastic packagings are notorious for the increased pollution they cause. The direct effects on humans are mainly due to the migration of compounds from plastic to the foods it contains. These compounds have various origins: additives, impurities, degradation products, uncontrolled reactions… For lack of being able to stop this migration, we chose to take advantage of it with new materials, called active materials. The objectives of these materials are to extend the shelf life of foods through a so-called “positive” migration. However, the use of natural additives is complicated due to their poor resistance to temperature. The problem is therefore to find natural additives resistant to the polymers’ extrusion temperatures, while stabilizing them. It is in this context that my thesis topic was set up within the Foodyplast project (POCTEFA). The thesis is divided into four parts. A state of the art is first presented. The following chapter details the various techniques used to produce and characterize our materials and the development of a new method based on mass spectrometry (LESA-MS). The third chapter discusses in detail the implementation of new materials stabilized by natural additives and their physico-chemical characterization. We have shown that the joint use of these additives (alpha tocopherol/ascorbic acid and alpha-tocopherol/tannins) significantly increases the stabilization effect on the polymer matrix (patented innovation). These materials have also shown to be recyclable up to 9 times without degradation. Finally, the last chapter potential of the new LESA-MS method (developed in Chapter 2) for its efficient of our materials. This method is compared to that of the current European standard and opens up real prospects for performing analyses in polymers for different applications
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Saracoglu, Mehmet. "FROTH FLOTATION PERFORMANCE ENHANCEMENT BY FEED CAVITATION AND MAGNETIC PLASTIC PARTICLE ADDITION." UKnowledge, 2013. http://uknowledge.uky.edu/mng_etds/9.
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Froth flotation is the most commonly used process to recover and upgrade the portion of the coal preparation plant feed that has a particle size smaller than 150 microns. Problems that occur when employing froth flotation in the coal industry include i) coal surfaces that are weakly-to-moderately hydrophobic, and ii) flotation systems that are overloaded and limited by insufficient retention time.
Research was performed to evaluate techniques that could be implemented to improve flotation performance under the aforementioned scenarios. Pre-aeration of flotation feed using a cavitation system was extensively evaluated in laboratory and full-scale test programs. The benefits of adding hydrophobic, magnetic plastic particles were also investigated to improve froth stability and increase bubble surface area.
Laboratory tests revealed that pre-aeration through a cavitation tube improved coal recovery by as much as 20 absolute percentage points in both conventional cells and flotation columns when treating difficult-to-float coals. Carrying capacity increased by 32% which was projected to provide a 4 t/h increase in flotation recovery for a typical 4-m diameter flotation column. Product size analyses suggest that the improved particle recovery was more pronounced for the finest coal fractions as a result of particle agglomeration, resulting from the use of the nucleated air bubbles on the coal surfaces as a bridging medium. In-plant testing of a commercial-scale cavitation system found that feed pre-aeration could reduce collector dosage by 50% when no additional air is added and by 67% when a small amount of air is added to the feed to the cavitation system. At a constant collector dosage, recovery increased by 10 absolute percentage points with cavitation without additional air and 17 absolute points when additional air is provided.
The addition of hydrophobic plastic particles to the flotation feed at a 10% concentration by weight was found to substantially improve froth stability thereby elevating the recovery and enhancing carrying-capacity. Test results showed that the primary flotation improvements were directly linked to the coarsest particle size fractions in the plastic material which supports the froth stability hypothesis. Combustible recovery was increased up to 10 percentage points while producing the desired concentrate quality.
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Hoover, Luke Daniel. "Large Strain Plastic Deformation of Traditionally Processed and Additively Manufactured Aerospace Metals." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1627570139729633.
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Demir, Hasan Ülkü Semra. "Synergistic effect of natural zeolites on flame retardant additives/." [s.l.]: [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/kimyamuh/T000514.rar.
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Cole, Thomas J. (Thomas Jonathan). "Manufacturability of microcellular foamed plastics : design of gas-addition device." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13058.
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Dawidson, Gabriella. "Determination of antioxidants and UV-stabilizers in the environment." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-158484.
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Synthetic antioxidants and UV-stabilizers are additives used in plastic products in order to protect the polymers from degradation caused by oxygen and ultraviolet light. Few studies have been performed about the presence of these compound groups in the environment and there is very sparse data on their distribution in the environment in Sweden. The objective of this study was to investigate the presence of ten common antioxidants and UV-stabilizers and two antioxidant metabolites [2-tert-butyl-4-methoxyphenol (1); 2,6-di-tert-butyl-4-methylphenol (2); 3,5-ditert-butyl-4-hydroxybenzaldehyde (3); 2,6-ditert-butylcyclohexa-2,5-diene-1,4-dione (4); 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)-methyl]-1,3,5-triazinane-2,4,6-trione (5); tris(2,4-ditert-butylphenyl) phosphite (6); [3-[3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoyloxy]-2,2-bis[3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoyloxymethyl]-propyl]3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate (7); octadecyl 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate (8); 2-tert-butyl-4-(5-tert-butyl-4-hydroxy-2-methylphenyl)sulfanyl-5-methylphenol (9); bis(2,2,6,6-tetramethylpiperidin-4-yl) decanedioate;2-hydroperoxy-2-methylpropane; octane (10); bis(3,3,5,5-tetramethylpiperidin-4-yl) decanedioate (11) and 4-methylhexyl-3-[3-(benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl]propanoate (12)] in water and snow in Stockholm and its surroundings. A method was developed for the determination in water by solid phase extraction (SPE) in order to extract and concentrate the compounds, followed by analysis by liquid chromatography – electrospray – tandem mass spectrometry (LC-ESI-MS/MS). Three compounds (2, 4, 11) were excluded from the method development since (2) and (11)could not generate a signal on the mass spectrometer whereas (4) could not produce a linear response. Due to the wide range of physicochemical properties of the analytes low recoveries were observed. Sampled water and snow from the Stockholm area was analysed and (3) and (9) were found in two of the water samples whereas (10) was observed in all water samples, below the quantification limit. Due to the lack of time, no methods were developed for the determination of the selected plastic additives in other environmental compartments.
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Wright, Stephanie. "The potential for microplastics to cause harm in the marine environment." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/18868.
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Plastic debris is an emerging environmental issue, with >10 million tons of plastics debris per annum entering the sea. Exposure to marine conditions facilitates the exponential fragmentation of plastic to micro-sized particles (microplastics). Marine and coastal sediments are a sink for microplastic pollution. Consequently, the ingestion of microplastics by a range of benthic marine invertebrates, including polychaete worms, has been reported in situ. Microplastics are vectors for priority pollutants capable of eliciting adverse health effects. However, the particle and chemical toxicity which microplastics could incur to ecologically-important marine invertebrates is unknown. This thesis aims to determine the potential for microplastics to cause harm in the marine environment, with a focus on benthic polychaete worms. Specifically, it assesses the potential particle toxicity which could arise from chemical-free microplastics; and the potential chemical toxicity which could arise from leached endogenous chemical additives or sorbed chemical pollutants. To address these, an integrative approach was employed, primarily using laboratory-based whole-sediment in vivo exposures, established cellular and whole-tissue toxicity assays, and analytical chemistry. For the first time, this thesis reports that chemical-free microplastics cause particle toxicity in the lugworm Arenicola marina. Feeding activity was reduced during exposure to 5% microscopic unplasticised polyvinylchloride (UPVC) by sediment weight, whilst exposure to ≥1% UPVC by sediment weight significantly reduced energy reserves relative to control animals. Evidence for the transfer and toxicity of endogenous additives from PVC to lugworms is provided. Lugworms exposed to 1% PVC by sediment weight exhibited a 70% increase in additive concentration, coinciding with inhibited mucus production and enhanced lipid reserves and oxygen consumption, compared to control lugworms. Ragworms (Hediste diversicolor) exposed to leached toxicants from bioplastic cigarette debris were found to exhibit significantly longer burrowing times, >30% weight loss, and >2-fold increase in DNA damage compared to control ragworms. Bio-concentration factors for nicotine – the biomarker of exposure - were 500 fold higher from leachates in seawater than from microfibres in sediment. Overall, this thesis provides evidence to suggest that the incorporation of microplastics into marine sediments can significantly impact the health of marine polychaete worms due to both particle and chemical effects. This emphasises the need to reconsider the classification of plastic as non-hazardous and questions whether we as humans are also at risk.
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Kilinc, Mert. "Production And Characterization Of Boron-based Additives And The Effect Of Flame Retardant Additives On Pet-based Composites." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610635/index.pdf.
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For the aim of production of poly(ethylene terephthalate), PET based flame retardant composites<br>boron based flame retardant additives, 3.5 mole hydrated zinc borate and boron phosphate were synthesized. Zinc borate was synthesized with the reaction of boric acid and zinc oxide in both laboratory and pilot scale reactors. Effects of reaction parameters on kinetics of reaction and final product particle size were evaluated. Boron phosphate was synthesized via dry, wet and microwave methods. In addition to the synthesized flame retardant additives, several non-halogenated flame retardant additives, which were commercially available, were also used. Composites were prepared using twin screw extruder and molded by injection molding, followed by characterization in terms of flame retardancy behavior, mechanical and thermal properties, and morphologies. Based on the results of first stage experiments, aiming to determine effective additives, different amounts and combinations of triphenyl phosphate, triphenyl phosphine oxide, zinc borate and microwave produced boron phosphate were chosen and used in PET matrix. Flame retardancy of the composites were determined by conducting horizontal burning rate and limiting oxygen index (LOI) tests. Smoke emissions during fire were also measured. According to the LOI test results, LOI of neat PET was determined as 21%, and with the addition of 5% boron phosphate and 5% triphenyl phosphate together, LOI was increased up to 36%. The smoke density analysis results implied that, boron phosphate was a successful smoke suppressant for PET matrix. In addition to flammability properties, tensile and impact properties of the composites were also improved with flame retardant additives and expecially with the addition of triphenyl phosphate.
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Yan, Yan, and 甄昕. "Automatic draft angles addition for moulded parts in an assembly." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29368960.
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Björnsdotter, Maria. "Leaching of Residual Monomers, Oligomers and Additives from Polyethylene, Polypropylene, Polyvinyl Chloride, High-density Polyethylene and Polystyrene Virgin Plastics." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-45888.
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Plastic debris are accumulating in our oceans and are degraded into smaller pieces which eventually becomes small enough to be available to lower thropic level organisms. Microplastics, commonly defined as plastic particles <5 mm, are globally distributed and found at remote locations far away from industrialized and populated areas. The effects of macro sized plastics is well understood whilst the effects of microplastics is hard to predict. It is known that microplastics act as transfer vectors for a wide range of toxic chemicals into organisms, and it is also known that the particle itself can cause toxic responses such as increased immune response and endocrine disruption. Researchers utilize virgin plastic pellets in order to determine the toxicological effect of the plastic particle itself, but resent research suggest that these virgin plastics may release chemicals that contribute to the toxic response and thus complicates the interpretation of the results. In present study, five different virgin plastics were allowed to leach in artificial seawater under conditions that mimic those used in particle toxicity studies. Plastics included were polyethylene, polypropylene, polyvinyl chloride, high-density polyethylene and polystyrene. Leachable monomers and oligomers were found in three of the five plastics tested: polyvinyl chloride, high-density polyethylene and polystyrene. Leached compounds from polyvinyl chloride were not identified due to time limitations. Aliphatic hydrocarbons in the size C14-C22 were leached out from high-density polyethylene in the concentration range 0.47 × 10-3 – 1.13 × 10-3 μg ml-1 within 24 hours. Polystyrene was found to leach styrene monomer which reached a concentration of 0.17 μg ml-1 within 24 hours.
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Custódio, Letícia. "Estratégias de controle de perdas em silagens de cana-de-açúcar." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11139/tde-12112013-110321/.
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O objetivo desse trabalho foi descobrir melhores estratégias de controle de perdas em silagens de cana-de-açúcar, utilizando combinações de aditivos químicos e microbianos ou estratégias de vedações. No primeiro experimento o intuito foi estudar estratégias de controle de clostrídios em silagens de cana-de-açúcar aditivadas com cal virgem. Os tratamentos foram: 1) controle; 2) 1,5% cal virgem (Cal); 3) 1,5% cal virgem + 5×105 ufc/g Lactobacillus plantarum Ma 18/5U (Cal+LP); 4) 1.5% cal virgem + 5×105 ufc/g Lactobacillus buchneri 40788 (Cal+LB); 5) 1,5% cal virgem + 0,07% nitrito de sódio (Cal+Nitrito); 6) 1,5% cal virgem + 0,15% benzoato de sódio (Cal+Benzoato). Como silos experimentais foram utilizados baldes plásticos com capacidade de 20 L. A cal não foi eficiente em diminuir perdas em relação ao controle (20,6% e 19,1%, respectivamente) já as combinações cal+Benzoato, cal+Nitrito, cal+LB e cal+LP, diminuíram perdas, apresentando os valores de 11,2%, 14,1%, 14,1% e 13,9%, respectivamente. A estabilidade aeróbia das silagens tratadas com cal (172 h), cal+Benzoato (155 h) e cal+Nitrito (223 h), foram maiores em comparação às tratadas com cal+LB (49 h), cal+LP (48,4 h) e controle (51,9 h). A silagem controle apresentou menores contagens de clostrídios (3,26 log ufc/g) e os tratamentos Cal e Cal+LB apresentaram as contagens mais altas (6,74 log ufc/g e 5,96 log ufc/g, respectivamente), enquanto Cal+nitrito (5,24 log ufc/g), Cal+LP (4,63 log ufc/g) e Cal+benzoato (4,41 log ufc/g) apresentaram contagens intermediárias. Nenhum tratamento imposto foi capaz de controlar o crescimento de clostrídios estimulado pela cal virgem. No segundo ensaio o objetivo foi comparar filmes plásticos na vedação de silagens de cana-de-açúcar. Os tratamentos impostos foram: 1) filme de poliamida 45?m, recoberta com manta de polietileno para proteção contra raios ultravioleta e danos físicos (PA45+M); 2) filme de polietileno coextrusado com poliamida, dupla face, 125?m (PA125); 3) filme de polietileno, dupla face, 200?m (DF). Três silos tipo trincheira foram preenchidos simultaneamente e durante o abastecimento a cana-de-açúcar picada foi tratada com benzoato de sódio na dose 0,15% da matéria natural. Decorridos 90 dias de armazenamento, os silos foram abertos e as silagens utilizadas como ingredientes para alimentação de vacas em lactação. Quinze vacas Holandesas (615 kg PV) foram alocadas aleatoriamente em três Quadrados Latinos 3x3, com períodos de 18 dias. O consumo de matéria seca (CMS). Amostras de leite foram coletadas para análises de proteína, gordura, lactose, caseína, ácidos graxos livres, sólidos totais, Nuréico e contagem de células somáticas. O óxido de cromo foi utilizado como marcador externo para estimar a produção fecal. As diferentes estratégias de vedação não influenciaram a qualidade das silagens e, consequentemente, não afetaram o CMS 19,9 kg/dia, a produção 25,1 kg/dia e a composição do leite (gordura 3,5%, proteína 3,3%, lactose 4,4%), das vacas. As diferentes estratégias de vedação utilizadas não influenciam a qualidade das silagens de cana-de-açúcar e o desempenho de vacas leiteiras e se mostraram efetivas para vedação de silos horizontais. No presente estudo, tanto a utilização de aditivos como a adoção de estratégias de vedação não foram efetivas em controlar perdas em silagens de cana-de-açúcar.<br>The aim of this study was to discover the best strategies to control losses in sugarcane silages, using combinations of chemical and microbial additives or covering strategies. In the first trial the aim was to compare strategies to prevent clostridium grow in sugarcane silages added with lime. Treatments were Control: no additives; L: 1.5% lime; L + LP: 1.5% lime + Lactobacillus plantarum Ma 18/5U (5×105 cfu/g fresh forage); L + LB: 1.5% lime + Lactobacillus buchneri 40788 (5×105 cfu/g fresh forage); L + N: 1.5% lime + 0.07% sodium nitrite; L + B: 1.5% lime + 0.15% sodium benzoate. As experimental silos were used plastic buckets with a capacity of 20 L. Mini bags were prepared with the following treatments 1) control, 2) 1.5 % of lime and 3) 1.5 % of lime + 5 × 105 cfu/g of L. plantarum, in order to analyze the pH drop at the onset of fermentation. The lime was not effective in decreasing losses compared to control silages (20.6% and 19.1%, respectively) however the treatments lime+Benzoate, lime+nitrite, lime+LP and lime+LB, decreased losses, showing lower values: 11.2%, 14.1%, 14.1% and 13.9%, respectively. The aerobic stability of silages treated with lime (172 h), lime+Benzoate (155 h) and lime+Nitrite (223 h) were higher compared to those treated with lime+LB (49 h), lime+LP (48.4 h) and control (51.9 h). The control treatment showed the lowest counts of clostridia (3.26 log cfu/g) and treatment with lime and lime+LB had the highest counts (6.74 log cfu/g and 5.96 log cfu/g, respectively), while lime+nitrite (5.24 log cfu/g), lime+LP (4.63 log cfu/g) and lime+benzoate (4.41 log cfu/g) showed intermediate counts of clostridia. None of additives combined with lime were able to provide butyric acid free silages. In the second trial the aim was to compare plastic films for sealing sugarcane silages. Treatments were: 1) polyamide film 45?m plus a protection against physical damage and ultraviolet light (PA45 + P), 2) polyethylene film coextruded with polyamide, black-on--white, 125?m (PA125), 3) polyethylene film, blackon- white 200?m (BW). Three trench silos were filled out simultaneously with chopped sugarcane treated with 0.15% of sodium benzoate (as fed basis). After 90 days of storage, the silos were opened and silages fed to lactating cows as total mixed rations. . Fifteen Holstein cows (615 kg BW) were randomly allocated into 3x3 Latin square with periods of 18 days. Dry matter intake, diet apparent digestibility, milk yield and milk composition were evaluated on days 14 to 18 in each period. Chromium oxide was used as external marker to estimate fecal excretion. Sealing strategies had no influence on silage quality and cows performance. Dry matter intake (19.9 kg /day), milk yield (25.1 kg/day), and milk composition (fat 3.5%, 3.3% protein, and 4.4% lactose) were quite similar across treatments. The different sealing strategies do not affect sugarcane silage quality and dairy cows performance and proven effective for sealing horizontal silos. In the present study, neither additives nor covering strategies were effective in reducing losses in sugarcane silages.
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Lott, Joseph Robert. "Design, Synthesis and Incorporation of Functional Additives into Multilayered Polymer Films." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1295673932.
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Monteiro, Aline Gomes de Sousa. "Desenvolvimento de aditivo plastificante e retardador de pega para gesso a partir da mucilagem da palma forrageira." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/9103.
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Previous issue date: 2015-09-30<br>The use of gypsum in the building industry has been growing since 1990. The current plaster coating quick and easy application and is being widely used in construction due to its low cost. However, implementation of this coating generates a huge amount of waste, since it has high speed hardening and have not yet developed economically feasible technologies or applications that allow its reuse. To reduce the waste generated by the production of gypsum, adding a fire retardant additive that provides increased setting time is needed, offering longer workability of the product. This study aims to develop an additive retardant plasticizer for gypsum blocks from the mucilage of Opuntia Ficus Indica forage Palma and the evaluation of their performance through laboratory tests. The following steps were followed: Processed palm mucilage extraction, specific additive mass testing and determination of pH, application in gypsum slurry for setting time tests, absorption, compression and consistency. Based on the results it can be concluded that the additive to be used as fire retardant and plasticizer values obtained satisfactory for use. The setting time of the evaluation confirmed their retarding action on the handle start and end time grip. In compression analysis, the smaller the percentage of the additive used, greater strength. The absorption test showed that the specimen was more moisture containing the A(wather) / G(Gipsum) ratio largest and the smallest value corresponds to the smallest amount of water with the addition of the additive. As for the consistency test, the pulp with the addition of the additive possessed satisfactory values compared to reference values.<br>O uso de gesso na construção civil vem crescendo desde 1990. O revestimento de gesso atual possui rápida e fácil aplicação e está sendo muito utilizada na construção civil devido ao seu baixo custo. No entanto, a execução deste revestimento gera um enorme volume de resíduos, já que possui alta velocidade de endurecimento e ainda não foram desenvolvidas tecnologias ou aplicações economicamente viáveis que possibilitem a sua reutilização. Para reduzir os resíduos gerados pela confecção do gesso, é necessário a adição de um aditivo retardador que propicie aumento no tempo de pega, oferecendo mais tempo de trabalhabilidade do produto. Diante essa situação, o presente trabalho tem como objetivo o desenvolvimento de um aditivo retardador plastificante para blocos de gesso a partir da mucilagem da Palma Forrageira Opuntia Ficus Indica e a avaliação do seu desempenho através de testes em laboratório. Nos procedimentos metodológicos foram seguidas as seguintes etapas: processo de extração da mucilagem da palma, ensaios de massa específica do aditivo e determinação de ph, como também a aplicação na pasta de gesso para os ensaios de tempo de pega, absorção, compressão e consistência. Com base nos resultados pode-se concluir que o aditivo para ser utilizado como retardador e plastificante obteve valores satisfatórios para o uso. A avaliação do tempo de pega confirmou sua ação retardadora no tempo de início de pega e final de pega. No ensaio de resistência à compressão, quanto menor a porcentagem utilizada do aditivo, maior e resistência. O ensaio de absorção mostrou que o corpo de prova com maior umidade era o que continha a relação a/g maior, e o menor valor corresponde a menor quantidade de água com a adição do aditivo. Quanto ao ensaio de consistência, as pastas com a adição do aditivo possuíram valores satisfatórios comparados aos valores de referência.
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Kuchnier, Caroline Nogueira 1983. "Estudo do efeito de aditivo extensor de cadeia multifuncional em blendas de PLA/PBAT." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266107.
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Previous issue date: 2014<br>Resumo: O poli(ácido lático), PLA, é um polímero biodegradável muito promissor para aplicações industriais e médicas. Contudo, algumas de suas características, como fragilidade à temperatura ambiente limitam sua potencial utilização e restringem sua degradação às condições de compostagem. Para promover modificações de propriedades do PLA este trabalho tem como objetivo o estudo de blendas com Poli(adipato-co-tereftalato de butileno), PBAT, outro polímero biodegradável. Buscou-se ainda, melhorar a compatibilidade entre os dois polímeros com a utilização do agente extensor de cadeia multifuncional Joncryl ADR-4368, que contém grupos epóxido reativos. Dois tipos de processamento foram adotados: em homogeneizador Drais e em reômetro de torque. Amostras dos polímeros puros e blendas em diferentes composições foram preparadas com e sem adição do extensor de cadeia. Na análise de calorimetria diferencial de varredura (DSC), a temperatura de transição vítrea (Tg) dos polímeros originais mostraram-se inalteradas nas blendas e revelou a imiscibilidade entre PLA e PBAT. O comportamento associado à fração cristalina apresentou variações em função da composição dos polímeros nas blendas e as transições térmicas não foram alteradas pelo extensor de cadeia. Análises de termogravimetria (TGA) mostraram o efeito de aumento na estabilidade térmica gerada pelo extensor de cadeia e o aumento da degradação térmica no processamento por injeção. A espectroscopia do infravermelho (FTIR) mostrou que grupos epóxido podem ter reagido com carboxilas e hidroxilas dos polímeros. A cromatografia por permeação em gel (GPC) mostrou que o extensor de cadeia promoveu aumento na massa molar do PLA, mas não apresentou o mesmo efeito no PBAT. Pela microscopia eletrônica de varredura (SEM), observou-se a presença de duas fases distintas. O extensor de cadeia promoveu a diminuição significativa no tamanho dos domínios da fase dispersa. Ensaios de resistência à tração mostraram que o PBAT aumentou a flexibilidade do PLA. Testes de resistência ao impacto mostraram aumento na resistência mecânica do PLA pela incorporação do PBAT. O extensor de cadeia reduziu a flexibilidade do PLA puro, mas aumentou a flexibilidade e a resistência mecânica nas blendas PLA/PBAT. Palavras-chave: Blendas poliméricas, plástico biodegradável, poli(ácido lático), aditivos<br>Abstract: Poly (latic acid) (PLA) is an attractive biodegradable polymer for industrial and medical applications. Although, some PLA properties like brittleness at room temperature restrict its potential applications and limit its full degradation only for composting conditions. The purpose of this work is to promote modifications in PLA properties by blending it with other biodegradable polymer, Poly (butylene-adipate-co-terephtalate) (PBAT). Joncryl ADR-4368, a multifunctional chain extender with epoxy functional groups was also used to increase polymers compatibility. Two processing methods were adopted: the samples in different compositions were processed in Drais homogenizer and torque reometer. Polymers and blends were processed with and without the chain extender. Differential Scanning Calorimetry (DSC) showed that the glass transition temperature (Tg) of the polymers did not change, which reveals immiscibility between PLA and PBAT. The behavior of the crystalline fraction exhibited variations depending on the composition of the blends and thermal transitions were not changed by chain extender. Thermo gravimetric analysis (TGA) showed that the chain extender caused an increase on thermal stability, and an increase of thermal degradation caused by injection molding processing. Infrared spectroscopy (FTIR) indicated that epoxy groups may be reacted with carboxyl and hydroxyl polymers functional groups. Gel permeation chromatograph (GPC) revealed that chain extender promoted molecular weight increasing in PLA but did not have the same effect on PBAT. Using Scanning electron microscopy (SEM) two phases morphology was detected. Chain extender promoted remarkable domains size reduction of the dispersed phase. Tensile strength tests demonstrated that PBAT enhanced flexibility and reduced brittleness of PLA. Impact strength tests showed an increment on PLA strength due to the presence of the PBAT. Chain extender reduced flexibility of PLA but also increased flexibility and tensile strength in PLA/PBAT blends. Keywords: polymer blends, biodegradable plastic, poly (latic acid), additives<br>Mestrado<br>Ciencia e Tecnologia de Materiais<br>Mestra em Engenharia Química
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Kleinfehn, Alex Patrick. "Scale-Up of Modifiable Poly(propylene fumarate) and Surface Functionalization of Additive Manufactured Scaffolds for Bone Tissue Regeneration." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1562679460809562.
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Bouscher, Robert F. "Advancements in Powder Coating Processing and in Real-time Film Formation Analysis of Thermoset Coatings." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1627566578541715.
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Soualhi, Hamza. "Optimisation de la viscosité des bétons à faible impact environnemental." Thesis, Cergy-Pontoise, 2014. http://www.theses.fr/2014CERG0712.
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Il est possible de modifier la composition des bétons utilisés dans le domaine de la construction pour réduire sensiblement le dégagement de CO2 associé à leur fabrication. Ceci est obtenu en réduisant significativement la quantité de clinker et en incorporant des matériaux de substitution appelés additions. Elles sont généralement moins réactives et demandent, pour maintenir un niveau acceptable de performances mécaniques et de durabilité, une réduction importante du dosage en eau. C'est le cas des bétons à faible impact environnemental. L'utilisation de superplastifiant dans ces bétons permet d'augmenter leur fluidité mais leur viscosité plastique reste toujours élevée ce qui induit des problèmes de mise en œuvre. La maîtrise de la viscosité plastique de ce type de béton est donc cruciale pour le développement de ces produits.Avec cet objectif fixé, dans la première partie de cette étude, un rhéomètre à béton, adapté aux spécificités des bétons à faible impact environnemental, a été développé. Associé à un protocole d'essai pertinent cet appareil permet de caractériser le comportement rhéologique non seulement des bétons courants mais également des bétons à faible impact environnemental.Ensuite, l'utilisation de ce rhéomètre dans un programme expérimental a permis de mettre en évidence l'effet des paramètres de compositions et notamment le taux de substitution et la nature des additions sur leur comportement rhéologique.Les résultats obtenus à partir de ce programme ont permis de proposer et valider un modèle de calcul de la viscosité plastique en considérant que le béton est constitué de deux échelles : pâte et granulats. Le modèle est applicable pour les bétons ordinaires et pour les bétons à faible impact environnemental. Une méthode d'optimisation de la viscosité a été proposée à l'aide du modèle<br>It is possible to modify the composition of conventional concrete used in the building field in order to reduce the emission of CO2 associated with their manufacture, particularly in the production of their constituents. This is can be achieved by significantly reducing the amount of clinker and incorporating alternative materials (mineral and chemical additions), which are generally have a lower reactivity and require a low quantity of water, with an adequate level of mechanical performance and durability. This is the case of concrete with low environmental impact. The use superplasticizer in the production of concrete allows increasing their flowability, despite the using of low content of water, but their plastic viscosity remains high and may cause problems of implementation. Controlling the plastic viscosity of this type of concrete is crucial to ensure the development of these products.Within this objective, a rheometer for concrete was developed. The relevant test protocol used for this apparatus enables to characterize the rheological behavior not only for conventional concrete, but also for concrete with low environmental impact.The use of the developed rheometer within an experimental program permits then to highlight the effect of the parameters of concrete compositions, and in particular the used additions (type and rate of substitution) on their rheological behavior.The obtained results from this program propose and validate a mathematical model for assessing the plastic viscosity, which is applicable for ordinary concrete and concrete with low environmental impact. An optimization method for calculating the plastic viscosity of the concrete has been proposed using this model
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Pinto, Maria Clara Cavalini 1987. "Avaliação das propriedades do gesso reciclado contendo aditivos." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258271.
Full textAbstract:
Orientador: Gladis Camarini<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo<br>Made available in DSpace on 2018-08-27T20:22:32Z (GMT). No. of bitstreams: 1
Pinto_MariaClaraCavalini_M.pdf: 8053440 bytes, checksum: bbe81de24c0023c7d27c30c6e2aeb3c0 (MD5)
Previous issue date: 2014<br>Resumo: As novas leis ambientais vem forçando a sociedade e empresas a mudar suas atitudes com relação à geração e destino dos resíduos. A produção indiscriminada desses rejeitos e a deposição incorreta do material vem causando impactos ambientais, apresentando-se como um grave problema de gestão pública, pois precisam ser descartados em aterros especiais. Um número limitado desses aterros especiais foram construídos para receber os resíduos de gesso, o que pode motivar a destinação dos resíduos de gesso para centrais de reciclagem. O gesso reciclado é obtido por meio de um simples processo de moagem e calcinação em temperaturas relativamente baixas. Comprovou-se, em trabalhos anteriores, que o gesso reciclado endurece rapidamente, reduzindo seu tempo de aplicação. Aditivos retardadores de pega do gesso têm sido estudados, contudo os testes são baseados em gesso comercial. A escolha de um aditivo adequado, bem como de sua dosagem, pode melhorar o tempo de pega do gesso reciclado, de modo a permitir a reaplicação do produto em obras e na produção de componentes. O objetivo deste trabalho foi estudar as propriedades do gesso reciclado, tanto no estado fresco como no endurecido, com o uso de aditivos retardadores: ácido cítrico, tânico, tartárico e citrato de sódio. Foram avaliadas a consistência, tempo de pega, cinética da temperatura, resistência à compressão, dureza e microestrutura. Os resultados mostraram que alguns aditivos foram capazes de alterar as propriedades do gesso reciclado. No estado fresco, o gesso reciclado teve seu tempo de pega aumentado por influência do ácido cítrico e do citrato de sódio. No estado endurecido, o ácido cítrico e o citrato de sódio reduziram a resistência à compressão e a dureza do gesso reciclado. O ácido tânico e o ácido tartárico, por outro lado, não alteraram significativamente o comportamento do gesso reciclado<br>Abstract: The new environmental laws are forcing the society and the enterprises to change their attitudes regarding the generation and the destination of wastes. The indiscriminate production of these wastes is causing environmental impacts, presenting itself as a serious problem of public management because it must be discharged in special landfills. A limited number of cells have been built for receiving sulfate waste, which may encourage this waste transfer to special recycling stations. The recycled gypsum plaster is obtained by a simple process of crushing and heating at relatively low temperatures. Previous works on gypsum recycling show that recycled gypsum plaster has fast setting and lack of workability. Gypsum retarders have been studied intensively, but the emphasis was always laid on commercial gypsum. The selection of suitable retarders and dosage can adjust the setting times of recycled gypsum plaster to a desired level to use this material again in construction works or to make components. The present study investigated the properties of recycled gypsum plaster with added citric, tannic, tartaric acid and sodium citrate to improve the performance in fresh and hardened states. The consistency, the setting times and kinetics of temperature, compressive strength, hardness and microstructure were evaluated. The results show that some admixtures can modify the recycled plaster properties. Setting times of the recycled plaster increased by influence of the citric acid and sodium citrate. Compressive strength and hardness were reduced by using citric acid and sodium citrate. On the other hand, tannic and tartaric acid did not change significantly the recycled plaster behavior<br>Mestrado<br>Arquitetura e Construção<br>Mestra em Engenharia Civil
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Mittag, Nadine. "Kombination von instrumentell-analytischen Verfahren und Biotests zur Untersuchung von Migraten aus Lebensmittelverpackungen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-25042.
Full textAbstract:
An Lebensmittelverpackungen wird heutzutage durch die zunehmende Nachfrage nach einfach zubereitbaren Fertigprodukten eine Vielzahl von Anforderungen gestellt. Diese Verpackungen sollen das Lebensmittel zum Beispiel vor Licht und Mikroorganismen schützen, weiterhin sollen sie verformbar, temperaturbeständig, mechanisch und chemisch belastbar sein. Sie sollen das Lebensmittel vor Aromaverlust bewahren, einen Gasaustausch ermöglichen und einen konstanten Feuchtigkeitshaushalt erhalten. Für den Verbraucher dagegen sind hauptsächlich das optische Erscheinungsbild und die Qualität des verpackten Lebensmittels von Bedeutung. Um diesen hohen Anforderungen entsprechen zu können, sind moderne Lebensmittel-verpackungen technologisch sehr hochwertige Produkte, die sich durch eine Kombination von unterschiedlichen Materialien auszeichnen. Im vielschichtigen Aufbau der Verpackung liegt gleichzeitig die Migrationsproblematik begründet. Durch den Einsatz von unterschiedlichen monomeren Ausgangsstoffen und resultierenden Reaktionsprodukten besteht ein Migrationspotential, welches von der Verpackung auf das Lebensmittel ausgeht. Das Ziel dieser Arbeit war es, die Migration aus verschiedenen Konservendosen und Kunststoffverpackungen, welche zum größten Teil derzeit als Verpackung im Lebensmittelsektor eingesetzt werden, zu untersuchen. Dazu wurden Gesamtmigrate mit unterschiedlichen Simulanzien (für wässrige, alkoholische und fetthaltige Lebensmittel und Milchprodukte) hergestellt. Einen Schwerpunkt stellte dabei die Analytik von speziell in fetthaltige Simulanzien migrierende Substanzen dar, da es sich hierbei um den sogenannten worst case handelt. Zusätzlich wurde versucht die migrierenden Substanzen mittels chromatographischen Methoden zu identifizieren und quantifizieren. Die kommerziell erhältlichen Standardsubstanzen beziehungsweise die isolierten Migrationsprodukte und die Gesamtmigrate wurden in einem Zellkulturtest (Neutralrottest) an humanen Zelllinien (Hep-G2, HT-29) auf ihr zytotoxikologisches Potential untersucht und bewertet. Ein Hauptaugenmerk sollte dabei auf migrierende Substanzen mit einem Molekulargewicht von unter 1000 Da gelegt werden. Moleküle von dieser Größe bilden eine mögliche Gefahr für den menschlichen Organismus, da sie durch den Gastrointestinaltrakt potentiell absorbierbar sind. Im Migrat des untersuchten Epoxyanhydrid-Coating (EP-AH-Coating) wurden die gesetzlich geregelten Substanzen BADGE, BADGE*2H2O und BPA identifiziert und quantifiziert. Deren Anteil an der Toxizität des Gesamtmigrates war mit circa 0,5 % sehr gering. Zur weiteren Aufklärung der Gesamttoxizität wurde das Migrat in vier Fraktionen (&lt; 400 Da, 400-700 Da, 700-1000 Da, &gt; 1000 Da) eingeteilt. Es wurde gezeigt, dass eine Fraktionierung des Migrates keinen Verlust des zytotoxikologischen Potentials auslöste. Weiterhin konnte gezeigt werden, dass die Fraktionen &lt; 400 Da und &gt; 1000 Da keinen zytotoxischen Effekt hervorriefen, im Gegensatz zu den Fraktionen zwischen 400-700 Da und 700-1000 Da. Die Fraktion 400-700 Da besaß das höchste zytotoxikologische Potential. Die Effekte der einzelnen Fraktionen lagen aber unter den bestimmten zytotoxikologischen Effekten im Gesamtmigrat. Bei der Untersuchung der gesammelten Fraktion 400-1000 Da konnte festgestellt werden, dass sich das zytotoxikologische Potential im Gegensatz zum Gesamtmigrat erhöht hat. Dies lässt auf Wechselwirkungen zwischen den Molekülen der einzelnen Fraktionen schließen, wobei offensichtlich die Substanzen &lt; 400 Da und &gt; 1000 Da eine inhibierende Wirkung auslösten. Neben den genannten gesetzlich geregelten Substanzen wurde die Substanz Cyclo-diBADGE als Leitsubstanz für die Fraktion 400-700 Da identifiziert, quantifiziert und im Zelltest untersucht. Durch diese vier (BADGE, BADGE*2H2O, BPA, Cyclo-diBADGE) Substanzen konnten nun 18 % (Hep-G2) bzw. 22 % (HT-29) der Gesamttoxizität des Gesamtmigrates unter der Annahme von additiven Effekten aufgeklärt werden. Für die Ketchupverpackung konnte der Aufbau der einzelnen Schichten aufgeklärt werden. Von der lebensmittelzugewandten Seite wurden 60 % des Gesamtmigrates durch migrierende Kunststoffadditive aufgeklärt und 17 % des Migrates von der Außenseite. Ein Problem stellte dabei das Antioxidans Irgafos 168 dar, welches sich während der Probenvorbereitung und der Probenlagerung zu seinem Oxidationsprodukt umwandelte und somit als Summenparameter bestimmt wurde. Die anderen migrierenden Substanzen lagen nach der Probenvorbereitung und Lagerung der Probe unverändert vor. 97 % der migrierenden Substanzen aus der Innenseite der Verpackung und 38 % aus der Außenseite besaßen ein Molekulargewicht &lt; 1000 Da und waren somit toxikologisch relevant. Im Migrat der lebensmittelzugewandten Seite wurden die Substanzen TBAC, DEHA, DBP, N-Ethyltoluolsulfonamid, Ölsäureamid, Erucamid, Irgafos-168-Äquivalente und Irganox 1076 identifiziert und quantifiziert. Diese Substanzen stellten 58,9 % des Gesamtmigrates dar. Das Migrat der Außenseite konnte nur zu 17,1 % durch die Substanzen TBAC, DEHA, DBS, DBP, N-Ethyltoluolsulfonamid, Ölsäureamid und Erucamid aufgeklärt werden. Von den in den Migraten der Kunststofffolie identifizierten Substanzen konnte nur für TBAC, DBP, N-Ethyltoluolsulfonamid und Ölsäureamid ein IC50-Wert im Neutralrottest ermittelt werden. In Abhängigkeit der untersuchten Zelllinie wurde ebenfalls für die genannten vier Substanzen der Anteil an der Toxizität des Gesamtmigrates unter Annahme, dass additive Effekte vorherrschen abgeschätzt. Dementsprechend konnte für die dem lebensmittelzugewandte Seite 16 % (Hep-G2) bzw. 9 % (HT-29) und für das Migrat der Außenseite 11 % (Hep-G2) bzw. 5 % (HT-29) der Gesamttoxizität aufgeklärt werden<br>Today many of demands are make on food contact material particularly in the field of convenience food. The packaging should protect the food before light and microorganism; the packaging should be also flexible, temperature and mechanical resistant and chemical inert, but also the nutrient-providing elements of foods ought to be protected. For the consumer are primarily the appearance and the quality of the food from interest. To meet these high requirements modern food contact materials are products of high technological quality. They mostly consist of a combination of variably materials, resulting in a multilayer structure. This composition of the packaging causes not only the desired positive effects, but also the migration risk of substances and substance groups from the packaging material into the food. Analyzing the migrating substances from different cans and plastic packing materials, which for the most part are currently in use in the food industry, was the aim of this work. For this purpose overall migrates were made with different kinds of food simulants (aqueous food (100 % H2O), alcoholic beverages (10% EtOH), diary products (50% EtOH) and fatty food (95% EtOH)). The main focus was set on the analytic of the migrating substances in fatty foods or simulants respectively, which is also called as the worst case. At first the migrating substances were identified and quantified chromatographically. Afterwards the cytotoxic potential of the commercial standard substances and isolated migrating substances were investigated by a cell culture assay (Neutral Red Assay) on human cell cultures (Hep-G2, HT-29). The attention was set on migrating substances with a molecular weight below 1000 Da. These substances are potentially able to be absorb by the gastrointestinal and so they might be a risk for the human health. The legally regulated substances BADGE, BADGE*2H2O and BPA were identified and quantified in the migrate of the investigated epoxy anhydride coating (EP-AH-Coating). Only 0.5 % of the cytotoxicity of the overall migrate could be explained via this three substances. For the further investigation of the cytotoxic effect of the overall migrate, the migrate was divided in four parts with different molecular weights (&lt; 400 Da, 400-700 Da, 700-1000 Da, &gt; 1000 Da). The single fractions were also determined in the neutral red assay for their cytotoxic potential. The fractions &lt; 400 Da and &gt; 1000 Da did not inhibit the cell viability. The fraction with the molecular weight 400-700 Da induced the highest cytotoxic effect on both cell lines. The single cytotoxic effects of the fractions 400-700 Da and 700-1000 Da were lesser than the effect of the overall migrate. But the effect of the fraction 400-1000 Da was higher than the effect of the overall migrate. Obviously there are interactions between the molecules of the single fractions, whereas the substances with a molecular weight &lt; 400 Da and &gt; 1000 Da had an inhibitive effect of the cytotoxic potential of the overall migrate. In the fraction 400-700 Da Cyclo-diBADGE was identified as a marker substance. Cyclo-diBADGE was isolated, quantified and investigated in the neutral red assay. Finally 18 % (Hep-G2) or 22 % (HT-29) of the cytotoxic effect of the overall migrate was estimate under the assumption of additional cytotoxic effects by these four (BADGE, BADGE*2H2O, BPA, Cyclo-diBADGE) substances. The multilayer structure of a second food packaging material for single ketchup portions was clarified. About 60 % of the migrating substances from the food contact side of the lamination were characterized by plastic additives and 17 % of the migrating substances of the non food contact side. 97 % of the migrating substances from the food contact side of the lamination exhibited a molecular weight below 1000 Da and might be a toxicological relevant. TBAC, DEHA, DBP, N-Ethyltoluolsulfonamide, Oleamide, Erucamide, Irgafos-168-äquivalents and Irganox 1076 were identified and quantified in the migrate on the food contact side of the lamination. In the neutral red assay a cytotoxic effect (IC50) was determined for the substances TBAC, DBP, N-Ethyltoluolsulfonamide and Oleamide. Depending on the investigated cell line 16 % (Hep-G2) and 9 % (HT-29) of the migrating substances from the food contact side of the lamination and 11 % (Hep-G2) and 5 % (HT-29) of the migrating substances of the non food contact side explained the cytotoxic effect of the overall migrates respectively
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Moammer, A. A. "Thermal management of moulds and dies : a contribution to improved design and manufacture of tooling for injection moulding." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6652.
Full textAbstract:
Thesis (PhD (Industrial Engineering))--University of Stellenbosch, 2011.<br>ENGLISH ABSTRACT: Injection moulding of polymer components is subject to ever increasing demands for improved
part quality and production rate. It is widely recognised that the mould cooling strategy employed
is crucial to achieving these goals. A brief overview of injection moulding units and different types
of injection moulds is given.
The modern Additive Manufacturing (AM) technology for processing metal powders such as
Direct Metal Laser Sintering (DMLS) and Selective Laser Melting (SLM) offers almost full
freedom to the mould designer. Some of these modern manufacturing methods based on metal
powders, which are able to produce complex cooling channels are analysed.
A drastic change has entered the mould design domain - shifting the paradigm from design for
manufacture to manufacture for design. In combination with suitable AM methods the concept of
surface cooling moulds can now be efficiently implemented.
This study presents a new approach of predicting the minimum cooling time required for the
produced part. Different cooling layouts are analysed taking the heat transfer into consideration.
The lumped heat capacity method is implemented in this research in order to determine the
minimum cooling cycle time required.
A new approach was developed to determine the most suitable cooling layout configuration, such
as conventional cooling, conformal cooling or surface cooling, required for a moulded part based
on its characteristics such as shape complexity, space available for the cooling layout, part
quality requirements, production volume, and product life cycle.
A mould cooling design process including simulation, reverse engineering and manufacturing of
the mould insert was implemented in this study.
In order to validate the generic model developed during the course of this research comparative
experiments were carried out to determine the difference in performance of injection moulding
using conventional or surface cooling methods. The experimental results showed a significant
improvement in part quality produced with reduced cycle times using the surface cooling method.<br>AFRIKAANSE OPSOMMING: ‘Injection Moulding’ van polimeer komponente word al meer gedruk vir verbeterde kwaliteit en
vinniger produksie tyd. Dit is orals bekend dat die gietvorm afkoeling strategie ‘n groot rol speel
om hierdie twee doelwitte te bereik. Eers word ‘n kort oorslag gegee van ‘Injection Moulding’
eenhede en van verskillende ‘Injection Moulding’ vorms.
Die moderne Aditatiewe Vervaardigingstegnologie vir die prosessering van metaal poeiers soos
bv. Direkte Metaal Laser Sintering (DMLS) en Selektiewe Laser Smelting (SLM) bied basies volle
vryheid ten opsigte van gietvorm ontwerp. Party van die moderne vervaadigings metodes, wat op
metaal poeiers gebaseer is, wat komplekse koelings kanale kan produseer word geanaliseer.
Die ontwerpers arena het ‘n groot verandering ondergaan deurdat die fokus van ontwerp vir
vervaardiging verskuif het na vervaardiging vir ontwerp. In kombinasie met toepaslike aditatiewe
vervaardigings metodes kan oppervlak verkoeling nou effektief geïmplementeer word.
Hierdie studie bied a nuwe manier om die minimum verkoelings tyd benodig vir ‘n part te
voorspel. Verskeie verkoelings uitlegte word geanaliseer waar hitte oordrag in ag geneem word.
Die “lumped heat capacity” metode word gebruik om die minimum siklus tyd te bepaal.
‘n Nuwe benadering is ontwikkel om die mees geskikste verkoelings uitleg soos bv.
konvensionele verkoeling, konvorme verkoeling of oppervlak verkoeling te bepaal vir ‘n spesifieke
part gebaseer op die part se vorm kompleksiteit, spasie beskikbaar vir verkoelings kanale,
kwaliteit vereistes en produk lewensiklus.
Die volgende is in die studie geïmplementeer: ‘n vorm verkoelings ontwerp proses met simulasie,
‘reverse engineering’ en vervaardiging van die vorm insetsel.
Om die generiese model te verifieer gedurende die studie is vergelykende eksperimente
uitgevoer om die verskil in prestasie te bepaal tussen die gebruik van konvensionele en
oppervlak verkoelings metodes. Die eksperimentele resultate het ‘n beduidende verbetering in
part kwaliteit getoon met ‘n verkorte siklus tyd tydens die gebruik van die oppervlag verkoelings
metode.
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Paul, Nadine. "Entwicklung chromatographischer und spektroskopischer Screeningmethoden zur Bestimmung der Migration aus Lebensmittelverpackungen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-61685.
Full textAbstract:
Neben der Sicherheit für Lebensmittel stehen auch immer mehr die Lebensmittelverpackungen im Fokus der Öffentlichkeit. Der Übergang von Stoffen aus der Verpackung in das Lebensmittel ist unerwünscht und gesetzlich reglementiert. Um den Verbraucherschutz zu gewährleisten, müssen Grenzwerte und gesetzliche Anforderungen eingehalten werden. Der Übergang von rechtlich geregelten und nicht geregelten Substanzen muss überprüft werden, was eine analytische Herausforderung darstellt. Die Untersuchung der migrierenden stickstoffhaltigen Substanzen aus Doseninnenbeschichtungen mittels eines Screenings aller migrierenden nicht-flüchtigen stickstoffhaltigen Substanzen mit einer molaren Masse kleiner 1000 Da wurde durchgeführt. Die Anwendbarkeit eines Stickstoff-selektiven Detektors für das Screening von Coating-Extrakten, welche stickstoffhaltige Verbindungen enthalten konnte gezeigt werden. Gegenstand der Untersuchung waren Vernetzersubstanzen, Flüssiglacke sowie Migrate der fertigen Beschichtung. Stickstoffhaltige potenziell migrierende Substanzen wurden zunächst in den Ausgangsmaterialien der Beschichtung identifiziert, um diese dann im Migrat der Beschichtung zu quantifizieren. Es sollte gezeigt werden, ob Substanzen, welche als Ausgangsstoffe im Lack eingesetzt werden, oder entstehende Reaktionsprodukte in ein Lebensmittelsimulanz migrieren. Um die Relevanz der migrierenden stickstoffhaltigen Verbindungen im Hinblick auf weitere nicht stickstoffhaltige migrierende Verbindungen zu zeigen, wurde das Gesamtmigrat der zur Verfügung stehenden Coatings bestimmt. Es zeigte sich, dass der Anteil von NCS an den insgesamt migrierenden Verbindungen zwischen 0,2 und 6,3 % liegt. Der Fokus des zweiten Teils der vorliegenden Arbeit liegt auf Lebensmittelverpackungen aus Kunststoff. Zunächst wurde eine HPLC-Methode mit Hilfe des Verdampfungslichtstreudetektors zur Bestimmung der Gesamtmigration mit dem Simulanz Sonnenblumenöl etabliert werden. Das Ziel dieser Untersuchungen ist, den Einfluss von Temperatur, Zeit und Schichtdicke auf das Migrationsverhalten von Siegelschichten für den Hochtemperaturbereich (> 70 °C) mit fetthaltigen Lebensmitteln mit Hilfe von statistischer Versuchsplanung vorherzusagen. Mit Hilfe einer statistischen Software konnte eine Regressionsgleichung zur Berechnung der Gesamtmigration auf der Grundlage eines Box-Behnken-Versuchsplans erstellt werden. Dabei hatte die Temperatur den größten Einfluss auf die Gesamtmigration. Die Einflüsse von Zeit und Schichtdicke waren im untersuchten Bereich des hier gezeigten Modells linear und stiegen mit Erhöhung der Temperatur. Weiterhin konnte je 10 °C Temperaturerhöhung eine Verdopplung des ermittelten Gesamtmigrationswertes beobachtet werden. Die Bestimmung der Additive aus den Ersatzsimulanzien 95 % Ethanol und Iso-Octan von Verpackungen sollte ebenfalls gezeigt werden. Ein Screening-Gradient zur Bestimmung von 25 Additiven in den Ersatzsimulanzien wurde etabliert. Die Identifizierung der migrierenden Additive erfolgte mittels der Detektoren UVD (DAD), FLD, ELSD und CLND. Mit Hilfe der verschiedenen Detektionsarten ist es möglich, die strukturelle Vielfalt der eingesetzten Additive abzudecken. Eine Absicherung der Ergebnisse konnte zudem über MS-Detektion erfolgen. Mit Hilfe der Untersuchungen wurden die gesamtmigrierenden Substanzen aus Verbundfolien zu 50 % (95 % Ethanol-Migrat) bzw. 10 % (Isooctan-Migrat) aufgeklärt. Die Konzentration der quantifizierten Additive zeigte im Verhältnis gesehen annähernd gleiche Werte. Der Unterschied in den ermittelten Gesamtmigraten (95 % Ethanol: 1,2 mg/dm2, Iso-Octan: 5,6 mg/dm2) konnte demnach nicht über die migrierenden Additive erklärt werden. Als weitere migrierende Substanzen wurden Ethylen-Oligomere identifiziert. Die Quantifizierung dieser erfolgte erstmals mit Hilfe der 1H-NMR-Spektroskopie. Die nahezu vollständige Aufklärung der Gesamtmigration einer Verbundfolie in den Ersatzsimulanzien konnte gezeigt werden. Die migrierenden Ethylen-Oligomere des Iso-Octan-Migrats wurden eingehender untersucht. Mit Hilfe von verschiedenen chromatographischen und spektroskopischen Methoden gelang eine Charakterisierung dieser im Migrat identifizierten Substanzen<br>Besides the safety of food the focus on food packaging material increases in public. The migration of substances from the packaging into food is undesired and regulated by law. To ensure consumer protection legal limits and requirements have to be kept. The migration of regulated und not regulated substances has to be verified which means an analytical challenge. The determination of nitrogen containing substances (NCS) from food can coatings by screening of migrating, non-volatile substances with a molecular mass below 1000 Da from the coatings was carried out. The applicability of a nitrogen selective detector for the screening of coating extracts which contain nitrogen containing susbtances was shown. For the investigations crosslinking substances, liquid lacquers as well as migrates of the finished coatings have been available for determination. Nitrogen containing and potential migrating substances have been identified first in the raw marterial of the coating in order to quantify them in the migrates of the coating. It should be shown if substances from the raw materials or reaction products migrate into the food simulant. In order to show the relevance of the migrating nitrogen containing substances in respect to other non nitrogen containing compounds the overall migration of the available coatings was determined. It could be shown that the amount of NCS in the overall migrating substances was between 0.2 and 6.3 %. Focus of the second part of the work was on food packing made of plastic. First an HPLC-method with ELS detection for the determination of the overall migration in sunflower oil was developed. Purpose of this determination was to predict the influence of temperature, time and thickness of the layer on the migration behavior with fatty food of sealing layers in high temperature range (> 70 °C) by means of design of experiments. A statistical software computed a regression equation for the calculation the overall migration based on a Box-Behnken-Design. The highest influence could be shown for the temperature. The modell showed a duplication of the determined overall migration with 10 °C increase of temperature. The determination of plastic additives out of the 95 % ethanol and isooctane migrates of packaging material should also be conducted. An HPLC-screening method for the determination of 25 additives in the fat substitutes was established. The identification of the migrating additives was carried out with UV detection (DAD), FLD, ELSD and CLND. By means of the different detection systems it was possible to cover the structural diversity of the mainly used additives. To insure the results MS detection was used. By means of this investigations a clarification of the total migrating substances of a multilayer film was 50 % (95 % ethanol) and 10 % (isooctane), respectively. The concentration of the migrating substances on the scale of things is nearly identical. The difference in the overall migration (95 % ethanol: 1.2 mg/dm2, isooctane: 5.6 mg/dm2) can not be clarified by migration of additives. As other migrating substances ethylen oligomers can be identified. The quantification was carried out for the first time with 1HNMR spectroscopy. An almost complete identification of migration substances of the overall migrate in food simulants can be shown. The migrating ethylen oligomers have been further investitgated. With the help of different chromatographic and spectroscopic methods a further characterisation of the migrating ethylen oligomers was successul
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Schneider, Jana. "Beitrag zur Wirkungsweise von Verzögerern beim Abbinden von Stuckgipsen." Doctoral thesis, TU Bergakademie Freiberg, 2009. https://tubaf.qucosa.de/id/qucosa%3A22717.
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In dieser Arbeit wurde der Einfluss verschiedener Additive (Carbonsäuren, Phosphonsäuren und Retardan P) auf die einzelnen Teilprozesse des Abbindens von Gips an technischen und synthetischen Halbhydraten unter vergleichbaren Bedingungen untersucht. Vorrangig bei der Keimbildung und beim Kristallwachstum wurde ein Einfluss der Additive beobachtet. Das pH-abhängige Wirkungsoptimum kann mit der Speziation der Additive erklärt werden. Ihre Wirkung wird durch Adsorption auf CaSO4-Oberflächen verursacht. Die Untersuchungen ergaben eine bevorzugte Ca-Affinität mit den Flächen (120) und (001) zunehmend von Citronensäure über Weinsäure, HEDP zu HDTMP. Die in verdünnten homogenen Lösungen erhaltenen Ergebnisse sind nicht direkt auf den Abbindeprozess in Pasten übertragbar. In-situ Ramanspektroskopie und Auswaschexperimente weisen in Pasten auf irreversible Adsorption und ein Überwachsen der Additive hin, was zur Abnahme ihrer Wirkung führt. Auf die Festigkeit der abgebundenen Gipskörper zeigen die Additive kaum Einfluss.
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Xu, Liqun. "Integrated analysis of liquid composite molding (LCM) processes." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1095688597.
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Thesis (Ph. D.)--Ohio State University, 2004.<br>Title from first page of PDF file. Document formatted into pages; contains xix, 245 p.; also includes graphics. Includes bibliographical references (p. 233-245).
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Schneider, Jana. "Beitrag zur Wirkungsweise von Verzögerern beim Abbinden von Stuckgipsen." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2010. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-27696.
Full textAbstract:
In dieser Arbeit wurde der Einfluss verschiedener Additive (Carbonsäuren, Phosphonsäuren und Retardan P) auf die einzelnen Teilprozesse des Abbindens von Gips an technischen und synthetischen Halbhydraten unter vergleichbaren Bedingungen untersucht. Vorrangig bei der Keimbildung und beim Kristallwachstum wurde ein Einfluss der Additive beobachtet. Das pH-abhängige Wirkungsoptimum kann mit der Speziation der Additive erklärt werden. Ihre Wirkung wird durch Adsorption auf CaSO4-Oberflächen verursacht. Die Untersuchungen ergaben eine bevorzugte Ca-Affinität mit den Flächen (120) und (001) zunehmend von Citronensäure über Weinsäure, HEDP zu HDTMP. Die in verdünnten homogenen Lösungen erhaltenen Ergebnisse sind nicht direkt auf den Abbindeprozess in Pasten übertragbar. In-situ Ramanspektroskopie und Auswaschexperimente weisen in Pasten auf irreversible Adsorption und ein Überwachsen der Additive hin, was zur Abnahme ihrer Wirkung führt. Auf die Festigkeit der abgebundenen Gipskörper zeigen die Additive kaum Einfluss.
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Carter, Justin B. "Vibration and Aeroelastic Prediction of Multi-Material Structures based on 3D-Printed Viscoelastic Polymers." Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1627048967306654.
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Keerthi, Sandeep. "Low Velocity Impact and RF Response of 3D Printed Heterogeneous Structures." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1514392165695378.
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