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Petrasovits, Lars-Arved. "Production of poly-3-hydroxyalkanoates in sugarcane /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18526.pdf.
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Brown, P. J. "Charge modulation spectroscopy of poly(3-alkylthiophene)." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596965.
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Field-effect transistors with conjugated organic active layers are an attractive possibility for cheap, low-end, high volume electronics. Possible applications include identity tags or smart cards, however for this to become commercial reality the field-effect mobility of the charge carriers must be comparable to those in α:Si, around 0.1-1cm<SUP>2</SUP>/Vs. Short chain oligomers deposited by vacuum sublimation have been shown to satisfy this requirement, however this deposition technique is expensive and is therefore less attractive to industry. Conjugated polymers may be fabricated so that they may be cheaply cast from solution, however until recently these materials were considered to be poor candidates for these applications due to the disorder inherent in the deposited films resulting in mobilities as low as 10<SUP>-4</SUP>-10<SUP>-3</SUP>cm<SUP>2</SUP>/Vs. Recent advances in the fabrication of poly(3-hexylthiophene) (P3HT) have resulted in high field-effect mobilities of up to 0.1cm<SUP>2</SUP>/Vs due to inter-chain self-ordering between the polymer chains. This raises interesting questions as to the nature of the charge carriers in the film as in this transport regime the mobility of the charge carriers suggests that the traditional hopping transport of localised polaronic charge carriers may require modification. The topic of this thesis is the characterisation of the charge carriers in P3HT so that the high mobilities may be explained. The technique used to probe these characteristics is Charge Modulation Spectroscopy (CMS) which allows the phase sensitive detection of the optical absorption spectra of the field-induced charge carriers in P3HT to be studied in-situ. This is a powerful technique as it allows the spectra to be studied as a function of modulation frequency, temperature and charge density. The conclusion reached for P3HT is that the charge carriers are no longer localised onto one chain, as for other disordered polymers, rather they take on a delocalised two-dimensional character. As the degree of intra and inter-chain order is of great importance to the electrical characteristics of P3HT, the characteristics of these charge carriers were also studied as a function of polymer structural purity and side-chain length (from butyl to dodecyl).
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Park, Taigyoo. "Dielectric relaxation behavior of poly(3-hydroxybutyrate)." Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06062008-163615/.
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Johnsson, Nathalie. "Composition and property study of adhesives based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate)." Thesis, KTH, Fiber- och polymerteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-301612.
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Lim klassificeras som ett ämne som kan hålla ihop två ytor så att de motstår separation. Dagens lim kan anpassas efter vilken applikation de ska användas till och kan ha ett stort antal olika egenskaper. De fysikaliska och kemiska egenskaperna av limmet är de viktigaste faktorerna för att bilda en bra limbindning. I stort sett alla syntetiska lim består idag av polymerer, varav de flesta är petroleumbaserade. För att skapa ett mer miljövänligt alternativ undersökte denna studie tillämpningen av poly(3-hydroxibutyrat- co-3-hydroxivalerat), PHBV med 36 eller 56 vikt% HV, som huvudkomponent i ett lim. Huvudfokus ligger på hur väl PHBV är lämpligt för användning som lim och hur olika tillsatser kan förbättra dess egenskaperna. Flera olika limblandningar innehållande PHBV, mjukgörare (sebacinsyra, dimetylsebacat, etylbutanoat eller tributylcitrat) och förtjockningsmedel (Abalyn eller Foralyn) skapades och undersöktes. Ett single lap skjuvtest utfördes med kopieringspapper, filterpapper och träpinnar som vidhäftningsmaterialet, medan ett avskalningstest undersökte användningen av kopieringspappersetiketter och plastetiketter på en glasflaska samt frukt. Båda testen visar att kopieringspapper har de mest lovande egenskaperna som en adherent för användningen av ett PHBV-baserat lim, både för PHBV innehållande 36 vikts% och 56 vikts% HV. Denna slutsats kunde dras då kopieringspapperet påvisade den starkaste bindningen med limmet. Ren PHBV uppvisade lovande häftstyrka och vidhäftning som ett smältlim. Tillsatsen av sebacinsyra tillsammans med Abalyn eller dimetylsebacat med Foralyn ökade limmets häftstyrka ytterligare. Vi fann också att lim som skapats med PHBV med 36 vikt% HV ger bättre hållfasthetsegenskaper. Framtida arbete innefattar mer exakta mätmetoder för att bestämma egenskaperna hos limblandningarna.<br>An adhesive is classified as a substance that holds two surfaces together and resists separation. Today’s adhesives can be modified according to various application demands, obtaining a large variety of properties. The most important factors of forming a good adhesive bond are the physical and chemical properties. Essentially all synthetic adhesives consist of polymers, most of them being petroleum-based. To obtain a more environmentally friendly option, this study investigated the use of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV with 36 or 56 wt% HV, as the main component in an adhesive. The main focus was to investigate on how well PHBV is suited for use as an adhesive and how different additives can improve the adhesive properties. Several different adhesive formulations containing PHBV, plasticizers (sebacic acid, dimethyl sebacate, ethyl butyrate, or tributyl citrate) and tackifiers (Abalyn or Foralyn) were created and investigated using various tests, such as single lap shear test, peel test, tackiness determination, optical analysis, and application testing. Single lap shear tests were performed using printing paper, filter paper, and wooden sticks as adherents, while peel tests explored the use of printing paper labels and plastic labels on a glass bottle and on fruit. It was determined that two PHBV adhesives, containing 36 wt% and 56 wt% of HV, performed best using printing paper as adherent. This conclusion could be drawn based on the good interaction between the adherent and the adhesive, thereby creating a strong bond. Pure PHBV with 36 or 56 wt% showed promising strength and tackiness properties as a hot-melt adhesive. The addition of sebacic acid together with Abalyn or dimethyl sebacate with Foralyn further increased the adhesive’s strength. It was also found that adhesive formulations created using a PHBV with a lower amount of HV (around 36 wt% of HV) yields better strength properties when used as an adhesive for paper labels. Future work involves more precise measurement methods to determine the properties of the adhesive formulations.
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Oberhoff, Ralph Wilhelm. "Modifizierung und Verarbeitung von Poly(3-hydroxybuttersäure-co-3-hydroxyvaleriansäure) (PHBV) mit kugelförmigen Mikropartikeln." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1132658328714-05584.
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Poly(3-hydroxybuttersäure-co-3-hydroxyvaleriansäure), PHBV, ist ein Copolyester, der auf biologischem Weg durch Bakterien herstellbar und ein steifes sowie relativ festes Polymer ist. Seine Biokompatibilität und biologische Abbaubarkeit weckt das Interesse für diverse Anwendungen in Pharmazie und Medizin. PHBV reagiert mit Abbau empfindlich auf zugleich thermische und mechanische Belastungen, was ein Problem für die Verarbeitung darstellt. Produkte aus PHBV aus einmal geschmolzenem und verarbeitetem Pulver sind hochkristallin. Daher ist das Material spröde. Ferner wirkt sich die hohe Kristallinität sowie eine große Änderung der Dichte beim Abkühlen der Schmelze nachteilig auf die Spinnbarkeit des Materials aus. Nach dem Passieren der Spinndüse ziehen sich die Spinnfäden zusammen, was die Gefahr eines Fadenrisses beim Spinnen erhöht. Aufgrund der relativ hohen Kristallinität des Materials und einer verzögerten Kristallisationskinetik bei gesponnenen Polymerfäden kommt es zur Nachkristallisation in einem erheblichen Ausmaß, die Fäden verkleben nach dem Aufwickeln auf den Galetten und reißen beim Abwickeln. Zur Behebung der Nachteile wurden Verarbeitungsbedingungen vor allem bei Schmelzspinnprozessen mit der Kolbenspinnanlage und bei Mischungsprozessen optimiert. Die Polymermischungen und ?verbundstoffe enthalten kugelförmige Mikropartikel verschiedener Morphologie, die zuvor synthetisiert und charakterisiert wurden. Vor allem mit Vinylgruppen modifizierte Silikat-Submikropartikel mindern die Sprödigkeit von PHBV.
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Modi, Sunny J. "Assessing the Feasibility of Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and Poly-(lactic acid) for Potential Food Packaging Applications." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1268921056.
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Dimopoulos, Alexandros Ioannis. "Characterization of poly(3-hexylthiophene) based Schottky diodes." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42227.
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This thesis describes the fabrication and electrical characterization of Schottky diodes based on the polymer semiconductor poly(3-hexylthiophene). Printed electronics may not be able to benefit from high vacuum processing, either for economic or technical reasons. The aim was to observe the effects on performance when Schottky diodes were built at atmospheric pressure. 200 nm thick films of poly(3-hexylthiophene) were formed on glass substrates by spinning a 1 wt% polymer solution in chloroform. Vacuum deposited aluminum and gold where used for the Schottky and ohmic contacts respectively. Two types of diodes were manufactured. One type (Au bottom) had its Schottky junction formed by evaporating aluminum onto the polymer under high vacuum. The other (Al bottom) had its Schottky junction formed by depositing the polymer onto aluminum at atmospheric pressure. The final yield of usable devices was 35% for Au bottom and 22% for Al bottom. The hole density and bulk mobility were derived from both DC and AC measurements. The bulk mobility was found to range from 2×10⁻⁵ cm²V⁻¹s⁻¹ to 6×10⁻⁵ cm²V⁻¹s⁻¹. The hole density was determined to be between 5×10¹⁶ cm⁻³ and 3x10¹⁷ cm⁻³. DC measurements showed that Au bottom devices had a current rectification ratio of 2×10⁴ at ±2 V, 100 times greater than Al bottom devices. The space charge limited current (SCLC) had to be considered to successfully model the DC behaviour. The small signal behaviour was modeled with a 2nd order series/parallel circuit, which was determined through impedance spectroscopy. Small signal performance of both device types was predicted to be poor. The corner frequency was determined to be less than 100 Hz for Al bottom devices, and less than 1 kHz for Au bottom devices. Large signal frequency performance of the diodes was tested with a half-wave peak rectifier. The maximum operating frequency was measured to be 40 kHz for Au bottom devices and 10 kHz for Al bottom devices.
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Zhao, Xiaoying. "Natural Rubber Toughened Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Bioplastic for Food Packaging Applications." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu154344332353769.
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Qian, Jun. "Investigation of crystallization of poly(3-hydroxybutyrate-CO-3-hydroxyvalerates) and their bamboo fiber reinforced composites." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/J_Qian_120906.pdf.
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Ding, Leiyuchuan. "Modification of High trans-Polybutadiene Copolymer and Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with Nano Fillers." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1377875542.
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Bergmann, Antje. "Alterungsmechanismen des biosynthetischen Polymers Poly-(R)-3-Hydroxybutyrat (PHB)." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=978409108.
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Miseikis, Lukas. "Attosecond transient absorption experiments in poly(3-hexylthiophene) targets." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/60582.
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In this thesis I present the development of a new type of experiment that extends the avenues of common time resolved measurements in the attosecond science field. The work presented here brings the tools of attosecond science to study electron dynamics in the systems that are the central topic in plastic electronics. A new experimental scheme is designed to study exciton formation and evolution in organic semiconductor Poly(3-HexylThiophene) (P3HT) that is used in organic solar cells. A variation of attosecond transient absorption spectroscopy was proposed to study the dynamics. The challenges of this experimental arrangement were to prepare the correct laser targets and both pump and probe pulses. Here I present the development of solid state polymer targets that were used for the transient absorption experiments. These targets have been succesfully prepared as free standing films in the range of 50 nm - 200 nm thickness and their X-ray absorption spectra were measured. Carrier envelope phase stable laser pulses centered at 1750 nm were achieved in a few optical cycle regime via Hollow Core Fiber (HCF) compression scheme developed in house. These pulses were used to drive High Harmonic Generation (HHG) beyond the 160 eV energy range in a differentially pumped Ne gas target. Strong CEP dependent half cycle cutoofs were observed in the HHG spectra confirming isolated attosecond pulses. X-ray absorption spectrum in P3HT targets was measured using this new source. Two routes for the optical pump generation have been explored. 17 fs, 2 mJ pulse was obtained from the 1750 nm driver via the cascaded third harmonic generation process in a non linear crystal and characterised using the SHG-FROG technique. This pulse was implemented as an optical pump in the transient absorption experiment. An interferometric optical setup was constructed that combines both the pump and the probe generation and the delay control between them. The setup was used to obtain the initial transient absorption experiment data.
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Lagoutte, Sébastien. "Nanocomposites polythiophènes/nanotubes de carbone alignés : élaboration, caractérisations et applications aux supercondensateurs en milieu liquide ionique." Thesis, Cergy-Pontoise, 2010. http://www.theses.fr/2010CERG0459.
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Le présent travail a porté sur l’élaboration d’électrodes à base de polymère conducteur et d’un tapis de nanotubes de carbone alignés pour les applications de supercondensateur.Dans la première partie de ce travail, nous avons porté notre attention sur le choix de nos matériaux et nous avons pu déterminer leur comportement électrochimique en milieu liquide ionique. Les deux polymères choisis : le poly(3-méthylthiophène) et le poly(3,4-diméthylthiophène) possèdent des propriétés très différentes en terme de capacitance, de potentiel d’oxydation, de résistance ou de cyclabilité. Afin d’allier ces propriétés entre elles, nous avons réalisé la synthèse de copolymères obtenus par voie électrochimique en milieu liquide ionique aprotique. Cette électro-co-polymérisation nous a permis d’obtenir une large gamme de matériaux aux propriétés variables selon la composition du polymère.Dans la deuxième partie de ce travail, nous avons optimisé la synthèse électrochimique d’un nanocomposite poly(3-méthylthiophène)/nanotubes de carbone alignés en milieu liquide ionique. Les matériaux obtenus offrent la propriété d’être « auto-supportés » et permettent ainsi de s’affranchir de collecteur de courant. La nanostructuration grâce aux nanotubes et l’absence de collecteur de courant nous ont permis d’améliorer d’un facteur 3 la capacitance spécifique de nos électrodes. Une optimisation des conditions d’élaboration des nanocomposites permettent d’atteindre une capacitance de 180F.g-1 dans EMITFSI à 30°C<br>The present work concerned the elaboration of electrodes containing electronic conducting polymer and a carpet of aligned carbon nanotubes for supercapacitor applications. In the first part of this work, we put our attention on the choice of our materials and we were able to determine their electrochemical behavior in ionic liquid. Both chosen polymers : poly(3-méthylthiopène) and poly(3.4-diméthylthiophène) possess very diffrent properties in term of capacitance, oxidation potential, resistance or cyclability. In the second part of this work, we optimized the electrochemical synthesis of a nanocomposite poly(3-méthyltiophène)/aligned carbon nanotubes in ionic liquid. The obtained materials offer the property to be "self-supported" and allow using themselves without current collector. And optimization of the conditions of nanocomposites elaboration allows reaching a capacitance of 180 F.g-1 in EMITFSI in 30°C
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venoor, varun. "Investigation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/Natural Rubber blends and Polystyrene/Polybutadiene Silica Nano-Composites." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492725718211967.
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Lauzier, Christian. "Morphology and crystallization behavior of nascent poly(3-hydroxybutyrate) granules." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41136.
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The structure of poly(3-hydroxybutyrate) (PHB) granules was examined by transmission and scanning electron microscopy (TEM and SEM). They are made of two distinct components: a solid shell (overlapping lamellar crystals) and a non-crystalline core.<br>TEM examination of sections of PHB granules revealed that, upon annealing, the core molecules transform into stacks of lamellar crystals of $ sim$50-70A in thickness. Fourier transform infrared results revealed the presence of bound water in a sample of freeze dried granules. Solid state $ sp{13}$C NMR results showed that the mobility of the granule core molecules was partly retained upon drying. A model for biosynthesis where emerging PHB chains in an extended conformation are simultaneously hydrogen bonded to water molecules is proposed.<br>Hydrolytic degradation of PHB granules in hot HCl proceeds through random scission of the molecules of both the crystalline shell and the non-crystalline core indiscriminately.
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Taidi, Behnam. "Control of the molecular weight of bacterial poly(3-hydroxybutyrate)." Thesis, University of Hull, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262472.
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Kumar, Avinesh Avi. "Charge transport in semi-crystalline poly(3-hexylthiophene) (P3HT) structures." Thesis, Queen Mary, University of London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538659.
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Marchant, Stephen. "Materials characterisation of the processible conducting polymer, poly(3-hexylthiophene)." Thesis, University of Greenwich, 1992. http://gala.gre.ac.uk/6238/.
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Kuo, Kao-Yu. "Optimisation of poly(3-hexylthiophene-2,5-diyl) based photovoltaic devices." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648726.
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Akaraonye, Everest Chukwuemeka. "Poly(3-Hydroxybutyrate), P(3HB) production and its biomedical applications." Thesis, University of Westminster, 2011. https://westminsterresearch.westminster.ac.uk/item/96500/poly-3-hydroxybutyrate-p-3hb-production-and-its-biomedical-applications.
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In this project enhancement of poly(3-hydroxybutyrate), P(3HB) production using a Gram positive bacteria, Bacillus cereus SPV and sucrose as the main carbon source was successfully achieved. Different modes of fermentation including shaken flask, batch, fedbatch and two-stage fermentation were investigated in the study. A modified G-medium was formulated and used throughout the study. Potassium and sulphate were identified as the main limiting factor for P(3HB) accumulation in Bacillus cereus SPV. By limiting the potassium phosphate concentration to 0.5 g/L K2HPO4 in the production medium, the dry cell weight, P(3HB) yield and P(3HB) concentration improved to, 7.21 g/L, 82 % dcw and 5.95 g/L respectively (i.e. 236, 115.8 and 830 % increase in dry cell weight, P(3HB) yield and P(3HB) concentration respectively). In addition, economic production of P(3HB) using agricultural/industrial waste (molasses) as the main carbon substrate was achieved. The study was also carried out in both shaken flask and 2L fermenter. The maximum P(3HB) yield achieved was 61.07 % dcw in 1L shaken flask and 51.37 % dcw in 2L fermenter. A novel wet cell PHA extraction was successfully developed in this project leading to high purity of the PHA produced with reduced crystallinity and efficient recovery. This is expected to save time, cost and enhanced continuous PHA production. Furthermore, a novel inexpensive and sustainable ‘compression moulding/particulate leaching’ technique for tissue engineering scaffold fabrication was developed. The novel technique enabled the production of biodegradable composite scaffolds of P(3HB)/microfibrillated cellulose and magnetic P(3HB) nanocomposite for possible applications in cartilage and bone tissue engineering, respectively. Detailed studies on the 2D and 3D composites showed that the inclusion of microfibrillated cellulose into the P(3HB) matrix enhanced the mechanical properties, hydrophilicity, introduced microtopography features, enhanced surface chemistry and biocompatibility of the composite material while inclusion of magnetic nanoparticles and ferrofluid, in addition to the above features added magnetic properties and microhardness to the composite materials. A unique controlled drug delivery system was developed with potential application in multiple drug delivery. The release study confirmed that the delivery system was able to control the release of BSA, a model protein. Finally, composite magnetic microspheres were also produced and characterised for their efficient use in the delivery of cancer drug and analyses performed showed that the composite constructs have superparamagnetic properties which would be useful for targeted delivery.
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Taba, Eduardo dos Santos. "Blendas com poli(3-hidroxibutirato) (PHB) e copolimeros aleatorios = comportamento de fases e cinetica de cristalização." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248788.
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Orientador: Maria Isabel Felisberti<br>Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica<br>Made available in DSpace on 2018-08-15T06:00:08Z (GMT). No. of bitstreams: 1
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Previous issue date: 2009<br>Resumo: Blendas do polímero biodegradável poli(hidroxibutirato) foram preparadas com os seguintes copolímeros aleatórios: poli(estireno-co-acrilonitrila)-SAN; poli(estireno-co-metacrilato de 2-hidróxietila)-S-Hema; poli(metacrilato de metila-co-vinil fenol-P(MMA-co-VPh). Os copolímeros SAN foram sintetizados via copolimerização em massa, enquanto os copolímeros S-Hema foram sintetizados pela copolimerização em solução utilizando DMF como solvente. Os copolímeros foram caracterizados por ressonância magnética nuclear (RMN) de H e C, cromatografia de permeação em gel (GPC), calorimetria exploratória diferencial (DSC) e análise dinâmico-mecânica (DMA). As blendas foram preparadas dissolvendo-se os polímeros em um bom solvente e adicionando-se à solução resultante um mau solvente para a coagulação dessas blendas. As análises das blendas por DSC, DMA e microscopia eletrônica de varredura (SEM) mostraram que todas elas são imiscíveis. A cinética de cristalização do PHB em blendas P(MMA-co-VPh)/PHB e SAN/PHB foi estudada por DSC. Esses estudos mostraram que a presença do copolímero P(MMA-co-VPh) causa a diminuição da taxa de cristalização do PHB e aumenta a energia de ativação do processo de cristalização do PHB. Para as blendas PHB/SAN, o efeito do copolímero em diminuir a taxa de cristalização do PHB é menor que nas blendas PHB/P(MMAco- VPh). Além disso, o teor de acrilonitrila no copolímero pouco afeta a taxa de cristalização do PHB. Os expoentes de Avrami ¿n¿ determinados para a cristalização do PHB nas blendas P(MMA-co-VPh)/PHB e SAN/PHB são aproximadamente iguais ao expoente ¿n¿ para o PHB puro indicando que o mecanismo de cristalização do PHB não se altera nas blendas. Sendo assim, este trabalho possibilitou o entendimento de aspectos importantes referentes ao comportamento de fases e à cinética de cristalização de blendas contendo PHB associado a copolímeros aleatórios.Os estudos cinéticos podem colaborar para a compreensão do comportamento de cristalização de copolímeros/PHB em equipamentos de processamento. Além disso, esse estudo pode ajudar na escolha do copolímero e de sua composição para um melhor controle da cristalização do PHB nessas blendas<br>Abstract: Blends of biodegradable poly(hydroxybutyrate) were prepared with the following random copolymers: poly(styrene-co-acrylonitrile)-SAN; poly(styrene-co-2-hydroxyethylmethacrilate)-S-Hema; poly(methylmethacrylateco- vinylphenol)-P(MMA-co-VPh).SAN copolymers were synthesized by bulk copolymerization; while S-Hema copolymers were synthesized by solution copolymerization using DMF as solvent. The resulting copolymers were characterized by nuclear magnetic resonance (RMN) of H and C, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and dynamic-mechanical analysis (DMA). Blends were prepared using coprecipitation method where a binary homogeneous soilution was added to a large volume of non solvent. DSC, DMA and scanning electron microscopy (SEM) analysis revealed that all the blends are immiscible in the entire composition range. Despite the immiscible blends, DSC analysis show that the copolymers interferes in the PHB crystallization, being capable of suppress this process in some blends. Crystallization kinetics of the PHB in PHB/P(MMA-co-VPh) and PHB/SAN blends was studied by DSC and the results revealed that the presence of P(MMA-co-VPh) copolymer decreases the PHB crystallization rate and increases the activation energy for the overall crystallization process. In respect to PHB/SAN blends, the influence of the copolymer in decrease the PHB crystallization rate is lower than the observed in PHB/P(MMA-co-VPh) blends. Moreover, the acrylonitrile concentration in the copolymer causes little effect in the PHB crystallization rate. The Avrami exponent ¿n¿ determined for the crystallization process in PHB/P(MMA-co-VPh) and SAN/PHB blends are approximately equal to the ¿n¿ exponent for pure PHB indicating that the crystallization mechanisms for pure PHB do not change in the blends. This work made possible the understanding of important aspects of the phase behavior and crystallization kinetics of random copolymers/PHB blends. The crystallization kinetics studies can collaborate for the understanding of the behavior of crystallization of these blends in processing equipments. Moreover, this study can help in the choice of the copolymer and its composition for better control of the crystallization of PHB in these blends<br>Doutorado<br>Físico-Química<br>Doutor em Ciências
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Hassaini, Leila. "Étude de la Morphologie et des Propriétés de Biocomposites Poly(3-Hydroxybutyrateco- 3-Hydroxyvalerate) (PHBV)/Farine de Grignons d’Olive." Thesis, Lorient, 2016. http://www.theses.fr/2016LORIS427/document.
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Ce travail a pour objectif de développer des biocomposites à base de poly(3-hydroxybutyrate-co-3-hydroxyvalérate) (PHBV) et de farine grignons d'olive (FGO) préparés par mélange fondu. Il s'articule autour de quatre parties. La première partie comprend une étude de la morphologie et des propriétés physiques des échantillons biocomposites PHBV/FGO aux taux de charge de 10, 20 et 30% en masse. Les résultats indiquent que le système PHBV/FGO se caractérise par une séparation de phase dont le nombre et la taille des particules de FGO augmentent avec le taux de charge. De plus, la stabilité thermique et les propriétés barrières vis à vis de la vapeur d'eau et de l'oxygène ont diminué. Par contre, l'incorporation de la FGO dans le PHBV induit une augmentation du module d'Young qui s'accentue avec le taux de charge. La même tendance est également observée avec le module de conservation déterminé par DMA. Dans la seconde partie, l'impact du PHBV-g-MA comme agent compatibilisant dans les biocomposites PHBV/FGO a été évalué en fonction du taux de charge. La caractérisation morphologique du système ternaire a révélé que la présence du PHBV-g-MA dans les biocomposites PHBV/FGO induit une meilleure adhésion interfaciale entre les particules de la FGO et la matrice PHBV en raison des interactions charge-matrice. En conséquence, une nette amélioration des propriétés mécaniques, viscoélastiques et barrières aux gaz (vapeur d'eau et oxygène) est observée. Dans la troisième partie, une modification chimique de la FGO avec le trimethoxy (octadecyl)-silane (TMOS) et son influence sur la morphologie et les propriétés physiques de biocomposites PHBV/FGO: 80/20 ont été étudiées. Les résultats révèlent une dispersion fine et homogène de la FGO traitée au TMOS dans la matrice PHBV avec en apparence moins de microvides en comparaison avec le biocomposite non modifié. Les propriétés physico-mécaniques du biocomposite PHBV/FGO modifiée sont sensiblement améliorées. La dernière partie consacrée à une étude du vieillissement hygrothermique dans l'eau de mer à 25 et 40°C de films de biocomposites PHBV/FGO: 80/20 avant et après modification, révèle que la FGO favorise la cinétique de dégradation du système PHBV/FGO indépendamment du traitement. Toutefois, le biocomposite PHBV/FGO traité avec des organo-silanes se caractérise relativement par une résistance à la dégradation hygrothermique à 25 et 40°C par rapport au reste des échantillons biocomposites<br>This work aims to develop a biocomposites based on poly(3-hydroxybutyrate-co-3-hydroxyvalérate) (PHBV) and olive husk flour (OHF) prepared by melt compounding. It's articulated around four parts. The first part includes a study of the morphology and physical properties of the PHBV/OHF biocomposite samples at the loading rates of 10, 20 and 30 wt%. The results indicate that the PHBV/OHF system is characterized by a phase separation whose number and size of OHF particles increases with the loading rate. Moreover, the thermal stability and the barrier properties against water vapor and oxygen have decreased. On the other hand, the incorporation of the OHF in the PHBV matrix induces an increase in the Young's modulus which is accentuated with filler content. The same trend is also observed with the storage modulus determined by DMA. In the second part, the effects of PHBV-g-MA used as the compatibilizer for PHBV/OHF biocomposites were evaluated as a function of the loading rate. The morphological characterization of the ternary system revealed that the presence of PHBV-g-MA in the PHBV/OHF biocomposites induces better interfacial adhesion between the OHF particles and the PHBV matrix due to filler-matrix interactions. Consequently, a significant improvement in the mechanical, viscoelastic and gas barrier properties (water vapor and oxygen) is observed. In the third part, a chemical modification of OHF with trimethoxy(octadecyl)-silane (TMOS) and its influence on the morphology and physical properties of PHBV/OHF: 80/20 biocomposites was studied. The results reveal a fine and homogeneous dispersion of the TMOS-treated OHF in the PHBV matrix with apparently fewer microvides compared to the unmodified biocomposite. The physical and mechanical properties of the modified PHBV/OHF biocomposite are significantly improved. The last part devoted to a study of the hygrothermal aging in sea water at 25 and 40°C of films of biocomposites PHBV/OHF: 80/20 before and after modification reveals that the OHF promotes the degradation kinetics of the PHBV/OHF system regardless of treatment. However, the organo-silane-treated PHBV/OHF biocomposite is relatively characterized by a resistance to hygrothermal degradation at 25 and 40°C compared to the rest of the biocomposite samples
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Novotný, Igor. "Roubování VTMOS na PHB." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-376859.
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Diploma thesis deals with the grafting of vinyltrimethoxysilane (VTMOS) onto poly(3–hydroxybutyrate)PHB. Subsequent characterization of the amount of grafted VTMOS and changes in the thermal properties associated with the rate of crystallization. The theoretical part deals with mechanism and the influences of grafting. In the experimental part VTMOS was grafted onto PHB without subjecting VTMOS to hydrolysis and subsequent crosslinking. By differential scanning calorimetry (DSC) and Avrami equation, the effect of grafted silane group on pure was studied. The MVR was used to compare the rheological properties of initial PHB, grafted PHB and crosslinked PHB by siloxane linkages.
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Ghaffar, Ahmed Mohamed el-Hadi Abdel. "Development of a biodegradable materials based on poly(3-hydroxybutyrate) PHB." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964167999.
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Rincón-Rosenbaum, Charlene. "Development of poly(3-octylthiophene) thin films for regulating osteoblast growth." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26493.
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The overall objective of this work was to assess the suitability of poly(3-octylthiophene) (P3OT) to sustain MC3T3-E1 osteoblast attachment and growth. The central hypothesis was that specific P3OT film properties (i.e., thickness, film preparation conditions, and level of doping) are able to regulate osteoblast functions (i.e., attachment and proliferation). Discrete and combinatorial techniques were utilized to prepare and characterize thin films of P3OT, a semiconductor in its undoped state, and to study its interaction with MC3T3-E1 osteoblasts.
In this work we demonstrate that P3OT is a suitable surface to sustain MC3T3-E1 attachment and proliferation with no observed cytotoxicity. We show that P3OT has an effect on MC3T3-E1 attachment and proliferation as area, circularity, and proliferation ratio are significantly different for P3OT compared to control surfaces. We also demonstrate that P3OT doping and film preparation conditions have an effect on osteoblast attachment and proliferation but that thickness over a low and high range does not affect osteoblast functions.
This work is significant because it contributes to the growing area of conducting polymers in biomedical applications and establishes P3OT as a potential cell substrate that sustains MC3T3-E1 attachment and promotes high levels of cell proliferation.
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Babinot, Julien. "Élaboration de copolymères amphiphiles à base de poly (3-hydroxyalcanoate)s." Phd thesis, Université Paris-Est, 2012. http://tel.archives-ouvertes.fr/tel-00804248.
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Les poly (3-hydroxyalcanoates) (PHAs) sont des polyesters aliphatiques produits et accumulés par des bactéries en tant que réserve de carbone et d'énergie. Ils sont constitués d'unités β-hydroxyesters et possèdent des chaînes latérales de longueur variable, pouvant être fonctionnalisées. Ils possèdent des propriétés de biodégradabilité et de biocompatibilité; ceci leur confère de vastes possibilités d'utilisation dans le domaine biomédical, notamment pour la mise au point de systèmes de libération contrôlée de principes actifs. Dans cette optique, nous nous sommes intéressés à la synthèse de copolymères amphiphiles de différentes architectures à base de PHAs, ainsi qu'à l'étude de leurs propriétés d'auto-association en milieu aqueux. Une méthode simple et efficace permettant le greffage d'oligomères de poly (éthylène glycol) (PEG) a tout d'abord été mise au point grâce à l'utilisation de la chimie " click ". Une série de copolymères diblocs bien définis PHA-b-PEG a ainsi pu être synthétisée par cycloaddition de Huisgen catalysée par le cuivre (CuAAC). Les copolymères diblocs à base de PHAs à moyennes chaînes latérales (PHA-mcl) ont montré leur capacité à s'auto-associer en milieu aqueux et à former des micelles monodisperses présentant une concentration micellaire critique très faible. Par la suite des copolymères de type greffés PHOU-g-PEG ont été synthétisés par addition thiol-ène. Les analyses par cryo microscopie électronique à transmission (cryo-TEM) ont montré que dans ce cas les copolymères s'auto-associaient en structures vésiculaires, ou polymersomes. Enfin, la synthèse de copolymères amphiphiles greffés porteurs de chaînes perfluorées PHOU-g-(F;PEG) a permis l'obtention de structures auto-associées plus complexes. Le cryo-TEM a en effet révélé la formation de micelles multicompartimentées, c'est à dire possédant un coeur présentant une séparation de phase entre les domaines hydrophobes et les domaines fluorés. Des tests biologiques préliminaires ont montré la cytocompatibilité de ces micelles
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Gomes, Henrique Leonel. "Fabrication and characterization of electronic devices based on poly(3-methlythiophene)." Thesis, Bangor University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358622.
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Arrad, Naoual. "Études spectroscopiques de complexes de Poly (3-Alkoxy-4-Méthylthiophène)-ADN." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28091/28091.pdf.
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Henderson, Robin A. "Physiology and biochemistry of poly 3-hydroxybutyrate production by Alcaligenes eutrophus." Thesis, University of Leicester, 1996. http://hdl.handle.net/2381/35250.
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Alcaligenes eutrophus NCIMB 40529 was grown in continuous culture (D=0.1h-1) under glucose, ammonium, potassium and oxygen limitation. The rates of PHB production (qPHB) were highest during ammonium-limited growth and lowest during glucose-limited growth. The PHB content of cells grown under ammonium limitation exhibited an inverse relationship to the dilution rate (D), whilst the rate of substrate (glucose) utilisation (qS) increased with D. It was concluded that glucose is utilised increasingly for the production of non-polymer biomass (NPB) as D increases, with the resulting diminution of PHB synthesis. PHB production from alternative carbon substrates was also studied in ammonium-limited chemostat culture (D=0.1h-1). PHB content, the rate of PHB production (qPHB) and qS varied substantially with the nature of the carbon source in the order lactate pyruvate glucose/gluconate fructose. qPHB was not related to umax in batch culture or to the relative oxidation-reduction states of the substrates, but was directly related to the qSsurplus i.e. the rate of substrate utilisation above that required solely for the production of NPB. The substantially higher qPHB from lactate than from glucose in ammonium limited chemostat culture reflected the inability of the cell to regulate lactate utilisation at D umax, whereas glucose utilisation is partially repressed under these conditions. Washed cells prepared from, glucose- and lactate-limited chemostat cultures (D=0.1h-1) metabolised glucose and lactate respectively at significantly faster rates than the cultures from which they were derived. Both types of washed cells synthesized PHB, indicating that the biosynthetic enzymes are constitutive; this was confirmed by assay of a representative biosynthetic enzyme in broken cells prepared from carbon- and ammonium-limited chemostat cultures. Washed cells also excreted pyruvate. It is suggested that carbon-limited cells are derepressed for carbon substrate uptake and catabolism, and that pyruvate excretion reflects the limited capacity of non-growing cells for pyruvate utilisation. Citrate synthase, a potentially important regulatory enzyme of the tricarboxylic acid cycle in A. eutrophus, was purified. The enzyme consisted of a single type of subunit with a Mr of 47,000, and exhibited a native Mr of 227,000. Citrate synthase activity displayed a hyperbolic dependence on both oxaloacetate (Km=1.2mM) and acetyl Co A (Km= 94uM) concentration, and a sigmoidal dependence of inhibition by NADH (I50=0.62mM). It is concluded that, apart from its insensitivity to AMP, the enzyme is similar to citrate synthases purified from other Gram-negative aerobes.
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CESAR, BERTRAND. "Synthese et caracterisation de copolymeres blocs polystyrene-b-poly(3-hexylthiophene)." Université Louis Pasteur (Strasbourg) (1971-2008), 1995. http://www.theses.fr/1995STR13227.
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Des copolymeres sequences polystyrene - poly(3-hexylthiophene) (ps-b-p3ht) ont ete synthetises et fractionnes. Leur caracterisation, par chromatographie d'exclusion sterique et spectroscopie uv-visible, a montre l'existence de copolymeres di et tri-blocs ainsi que d'agregats. La presence de triblocs est une donnee nouvelle concernant le mecanisme des reactions de propagation et de terminaison de la polymerisation oxydative des poly(3-alkylthiophenes). L'etude en solution, par diffusion de neutrons, de copolymeres fractionnes comportant une sequence polystyrene deuteriee a ete realisee. Elle a permis de mettre en evidence la structure lineaire des sequences p3ht, et une faible agregation de ces chaines a l'etat dope. L'etude a l'etat solide par calorimetrie differentielle et diffraction des rayons x, permet d'observer une separation en microphases des sequences ps et p3ht. L'obtention de morphologie en nids d'abeille, a partir de films de copolymeres dopes, est un argument en faveur de l'association en micelles des copolymeres, dans les conditions de l'experience. Le dopage p des copolymeres a ete effectue en solution et l'influence du temps d'exposition au dopage etudiee. Des mesures de conductivite en fonction de la frequence, montrent qu'une tres faible fraction en p3ht est necessaire pour obtenir des conductivites compatibles avec les absorbants hyperfrequences. L'etude des proprietes optoelectroniques de ces copolymeres, tant a l'etat neutre qu'a l'etat legerement dope, a permis l'elaboration de diodes electroluminescentes organiques dont les caracteristiques sont tres superieures a celles des diodes electroluminescentes developpees a partir de poly(3-alkylthiophenes)
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Černeková, Nicole. "Studium reologických vlastností a biodegradace poly (3-hydroxybutyrátu-co-4-hydroxybutyrátu)." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-444538.
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This diploma thesis deals with the characterization of rheological properties and biodegradation of a poly(3-hydroxy-co-4-hydroxybutyrate), a copolymer produced by a strain of Cupriavidus malaysiensis. The theoretical part focuses on the rheology and degradation of polymers in general. It also contains the basic characteristics of polyhydroxyalkanoates and deals in more details with the description of the studied copolymer, its properties, synthesis, decomposition and possibilities of its applications. In the experimental part, the given copolymer was investigated in its native form and also in the form of copolymer mixtures filaments, which were enriched with additives (stabilizers and plasticizers). In terms of rheology, the samples showed pseudoplastic behaviour, which was slightly limited by the plasticization of the material. The highest thermal stability observed as a function of changes in complex viscosity over time was observed in a sample of a copolymer mixture containing stabilizers and plasticizer Citrofol BII. The plasticization also caused significant changes in thermal properties, especially crystallinity, which decreased compared to the native copolymer. In vitro degradation studies of samples in the form of films prepared by dissolving copolymer mixtures in chloroform were performed in phosphate buffer with lipase, in simulated body fluid and in synthetic gastric juice. The course of the process itself was characterized by the method of determining the molecular weight (SEC-MALLS) and the weight loss over time (gravimetrically). The results showed that the analysed samples are subject to degradation in all used environments. The most considerable molecular weight loss after 105 days (76 %) was observed in the sample containing stabilizers and plasticizer Citrofol BII in the environment of synthetic gastric juice. The most extensive gravimetric weight loss was attributed to the sample with stabilizers and without plasticizers, in the environment of phosphate buffer with lipase, specifically by 79%.
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Gonfa, Belete Atomsa. "Fabrication of solar cells from poly(3-hexylthiophene) and ZnO Nanostructures." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/2289.
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Mestrado em Ciência dos Materiais<br>As células fotovoltaicas à base de compostos orgânicos e de híbridos do tipo orgânico/inorgânico têm recebido bastante atenção devido à sua potencial aplicação como fonte de energia limpa e económica. A
utilização de nanoestruturas neste tipo de dispositivos tem também recebido especial atenção já que o confinamento quântico a elas associado promove a percolação, facilitando a passagem dos portadores de carga o que aumenta a sua eficiência. Nesta tese foram preparados
dispositivos fotovoltaicos “bulk heterojunction” através da mistura de poli(3-hexiltiofeno) com diferentes nanoestruturas de ZnO.
As nanoestruturas de ZnO (nanopartículas, nanofios e naofibras) foram preparadas por diferentes técnicas e caracterizadas por XRD,
espectroscopia no UV-Vis, SEM e TEM. As nanopartículas e os nanofios de ZnO foram preparadas por métodos químicos em solução e
decomposição térmica de acetato de zinco dihidratado respectivamente.
As naonofibras de ZnO foram preparadas por calcinação de nanofibras compostas por alcóol polivinílico e acetato de zinco preparadas por
“electrospinning”. As nanoestruturas preparadas foram ainda funcionalizadas com o ácido pireno-1-carboxílico. As nanoestruturas preparadas, funcionalizadas ou não funcionalizadas, foram misturadas com soluções de P3HT de modo a preparar dispositivos fotovoltáticos em duas configurações distintas. Numa delas os eléctrodos consistem em ITO e o alumínio depositado por evaporação térmica, na outra, os eléctrodos
consistem em ITO e tinta de prata. O primeiro tipo de configuração utilizou a seguinte sequência: vidro/ITO/PEDOT:PSS/camada fotoactiva/Al. Na segunda configuração a sequência utilizada foi:
vidro/ITO/ZnO/ camada fotoactiva/ PEDOT:PSS/Ag. As camadas de PEDOT:PSS bem como as camadas fotoactivas foram depositadas por spin coating. A caracterização dos dispositivos foi feita através de medições da
corrente-tensão sob condições simuladas de iluminação padrão. Os dispositivos preparados apresentaram actividade fotovoltaica mas a sua
eficiência ainda precisa de ser melhorada.
ABSTRACT: Organic and organic/inorganic hybrid solar cells have been receiving a significant amount of attention due to their potential to yield
environmentally friendly and cheap source of energy. As a result they are being investigated widely. Making use of nanostructures in such devices has also received a great attention as they provide percolative pathways for charge carriers by quantum confinement, helping in the improvement
of the efficiency of the devices. In this thesis bulk heterojunction photovoltaic devices have been produced by blending different ZnO nanostructures and surface functionalized ZnO nanostructures with poly- 3-hexylthiophene.
ZnO nanostructures (nanoparticles, nanowires and nanofibers) have been produced by different techniques and characterized by XRD, UV-Visible
spectroscopy and SEM. ZnO nanoparticles and ZnO nanowires were prepared by wet chemical synthesis and thermal decomposition of zinc
acetate dihydrate respectively. ZnO nanofibers were prepared by calcination of polyvinyl alcohol/zinc acetate composite nanofiber, which
had been produced by the electrospinning process. These nanostructures were also surface functionalized with pyrene-1-carboxylic acid and
characterized. Subsequently, these nanostructures and their surface functionalized forms were used to fabricate photovoltaic devices by combining them with P3HT and its whiskers. The photovoltaic devices have been prepared in two different configurations. In some ITO and aluminium deposited by thermal evaporation were used as the
electrodes, while in the others ITO and silver paste were used. The first set of devices had the order glass/ITO/PEDOT:PSS/photoactive layer/Al,
while the latter had the order lass/ITO/ZnO/photoactive layer/ PEDOT:PSS/Ag paste. The PEDOT:PSS and the photoactive layers were deposited by spin coating of the suspension of PEDOT:PSS in water and the suspension of the ZnO nanostructures in the poly-3-hexylthiophene
solution respectively. The photovoltaic cells were finally characterized by current-voltage characteristics measurement under simulated standard illumination conditions. The photovoltaic devices prepared have demonstrated photovoltaic properties, but their efficiencies need further
improvement.
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Handrick, René. "Neuartige Poly(3-Hydroxybutyrat) Depolymerasen aus Paucimonas lemoignei und Rhodospirillum rubrum." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10934926.
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Rincón-Rosenbaum, Charlene. "Development of poly(3-octylthiophene) thin films for regulating osteoblast growth." Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26493.
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Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: J. Carson Meredith; Committee Member: Hang Lu; Committee Member: Joseph Schork; Committee Member: William Koros; Committee Member: Yadong Wang. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Ciou, Chun-Yu, and 邱淳羽. "Crystallization Behavior and Characterization of Poly(3-Hydroxybutyrate)/LDH and Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)/LDH Nanocomposites." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/2uugfc.
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碩士<br>國立中興大學<br>材料科學與工程學系所<br>101<br>Poly(3-hydroxybutyrate)(PHB) and Poly(3-hydroxybutyrate-co-3-hydroxyvaler- ate)(PHBV) have been produced by many types of micro-organism and are completely biocompatible and biodegradable in the environment by either hydrolytic degradation or enzymatic degradation via variety of bacteraia, resulting in water and carbondioxide. By adding inorganic materials into polymer matrix, the physical properties of composite materials could be enhanced to reach a lot of applications. In this study, the Mg-Al layered double hydroxides (LDH) prepared using one-step coprecipitation method were sucessfully synthesized to intercalate oleate into the interlayer spacing of LDH (assigned as OLDH). The surface property of LDH was changed from hydrophilic to hydrophobic characteristic. The PHB/OLDH and PHBV/OLDH nanocomposites were fabricated using solvent intercalation method. XRD analysis of OLDH showed a diffraction peak related to (0 0 3) plane, which contained the interlayered spacing increased from 0.83nm of LDH into 3.4nm with the addition of oleate. FT-IR spectrum revealed the absorption bands at 1408 and 1547 cm-1 weve associated with the stretching vibration of COO- group. The data at 3012 and 2800-3000 cm-1 were attributed to C-C and C-H of alkyl, respectively. These results demonstrated the presence of oleate ions in OLDH. The ratio of Mg:Al determined by ICP-OES was about 2:1. The amount of organic compound intercalated into the spacing obtained by TGA was 32.6 wt%. The structure and morphology of nanocomposites investigated using X-ray diffraction and TEM micrographs showed the OLDH were randomly dispersed and exfoliated into the PHB and PHBV matrix. Effect of OLDH on the crystallization behavior was investigated using a differential scanning calorimetry (DSC) and polerized optical microscopy. Isothermal crystallization results of PHB/OLDH and PHBV/OLDH nanocomposites showed that the addition of OLDH into PHB induced more steric hindrance of the diffusion of PHB, reducing the transportation ability of polymer chains during crystallization, thus decreasing the crystallization rate and increasing folding surface free energy. The thermal and mechanical properties of nanocomposites were observed by TGA and DMA. Through catalytic action, the T10d was lowered by 25~50℃. The storage modulus was increased and can be ascribed to the reinforcing effect of OLDH. The more content of OLDH, the higher storage modulus increased. For the in vitro degradation experiments, the film soaked in a solution containing Caldimonas manganoxidans was observed by microbalance. Compared to different HV content of film, the weight loss was increased with the same degradation time, illustrating that the degradation rate was increased by increasing content of HV. The degradation rate was strongly affected by the crystallinity, which is in the order of PHB>PHBV5>PHBV12. By adding OLDH, the degradation rate of nanocomposite did not significantly change.
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Ho, Mao-Hsun, and 何茂熏. "Preparation and characterization of electrospun Fe3O4/poly(3-hydroxybutyrate) and Fe3O4/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanofibers." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/77423046945366981078.
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碩士<br>國立中興大學<br>材料科學與工程學系所<br>100<br>This study is focused on the preparation of Fe3O4/poly(3-hydroxybutyrate) (PHB) and Fe3O4/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electrospun fiber containing high porosity and surface area with interconnected pore network. The structure of prepared PHB and PHBV fibers is similar to the dimension of extracellular matrix (ECM). The electrospun Fe3O4/PHB and Fe3O4/PHBV composite fibers were achieved with biocompatibility and magnetic properties.
The micrographs of scanning electronic microscopy (SEM) illustrate that the fiber diameter was distributed in the range of 160 nm ~ 660 nm and 2.4 μm ~ 8.7 μm for PHB, PHBV5 and PHBV12 fiber in 2,2,2-trifluoroethanol (TFE) and chloroform (CHCl3) solvent, respectively. The structure and property of PHB, PHBV5 and PHBV12 fiber were investigated by different scanning calorimeter (DSC) and X-ray diffraction (XRD). The DSC results indicated that the melting endotherm slightly shifted to low temperatures as the content of PHV increased. At the same time, XRD analysis of PHBV fiber show the (110) diffraction peak became apparent with 12% PHV content under the electric field.
The monodispersed 6 nm Fe3O4 nanoparticles have been prepared through thermal decomposition process. The structure and properties of fabricated nanoparticles can be analyzed by transmission electron microscopy (TEM), superconducting quantum interference device (SQUID), and XRD. The monodispersed 6 nm Fe3O4 nanoparticles contain superparamagnetic property. The electrospun Fe3O4/PHB and Fe3O4/PHBV fiber with high porosity and surface area with interconnected pore network have been suceessfully prepared. DSC analysis of Fe3O4/PHB and Fe3O4/PHBV composite fibers fabricated in TFE solvent presence of Fe3O4 nanoparticles will promote good arrangement of the molecular chain in PHB and PHBV5 under an electric field. XRD results of the PHB, PHBV, Fe3O4/PHB and Fe3O4/PHBV composite fibers show similar tendence, which indicates the Fe3O4 does not significantly affect the crystalline structure of PHB and PHBV in the electrospinning process.
For the in vitro degradation experiments, the fibers soaked in a solution containing bacteria was observed by SEM. Experimental result showed that the structural changes of PHB and PHBV fiber occurred during the in vitro degradation, in which the fiber pore formed on the surface of PHB and PHBV. Erosion of both PHB and PHBV fibers increased with increasing incubation time. Compared to different PHV content of fiber, the SEM micrographs illustrate that the degradation rate was increased by increasing content of PHV. From the SEM results after decomposition for 2 days, the PHB fiber was significantly destroyed. Gel Permeation Chromatography (GPC) was used to investigate further the molecular weight changes of PHB. When weight percentage of molecular weight (Mw) started to decay to around 240000 ~ 230000 g/mole (after 6 hr), and the next step of degradation has been occured involving the weight loss. However, the system of PHBV showed little molecular weight changes, in which the degradation began to decompose from the surface of fibers. After the specimen was washer using water, the lower molecular weight of sample might be removed from the surface of fiber. Then the fibers soaked in a solution containing fungi in vitro degradation test showed that the fiber surface is gradually covered with mycelium as degradation time increases, which led to the residual amount. The result indicated that fungi do not significantly affect increasing the degradate rate of PHB and PHBV. These results can serve as a reference for future animal studies.
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Tung, Tsu-Chien, and 童子謙. "Synthesis of Poly(3-hexylthiophene), Poly(3-hexylselenophene) and Poly(3-hexylthiophene-alt-3-hexylselenophene) by Direct C-H Bond Arylation via N-Heterocyclic Carbene Palladium Catalysts." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/4w89ub.
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碩士<br>國立交通大學<br>應用化學系碩博士班<br>102<br>In this study, we have successfully introduced commercial N-heterocyclic carbene-based palladium catalysts to conduct direct C-H bond arylation polymerization and poly(3-hexylthiohphene) (P3HT), poly(3-hexylselenophene) (P3HS), and poly(3-hexylthiophene-alt-3-hexylselenophene) (P3HTS) were synthesized accordingly.
Under our optimized conditions, high molecular weight P3HT (Mn = 26.9 k, PDI = 3.56) with high head-to-tail regioregularity (94%) was prepared through C-H bond arylation polymerization catalyzed by NHC-Pd(II) [1,3-Bis(2,6-diisopropylphenyl)imidazol-2-ylidene]chloro[3-phenylallyl]palladium(II). P3HS was obtained by a similar manner and this is the first example of preparing P3HS by direct C−H bond arylation. NHC-Pd(II) exhibits a wide range of working temperature spanning from 70°C to 140°C) and good catalytic reproducibility relative to conventional phosphine-based palladium catalysts. For this first time head-to-tail poly(3-hexylthiophene-alt-3-hexylselenophene) was prepared by direct C-H bond arylation polymerization by the help of NHC-Pd(II), offering an opportunity to study the physical properties of P3HTSThe results reveal that P3HTS retains many advantageous properties of P3HT and P3HS, including broad UV-Vis absorption, good crystallinity, and high thermal stability (Td = 428 °C). Moreover, owing to the regular alternating arrangement of thiophene and selenophene units, it also exhibits various advantages over either P3HT or P3HS, such as more red-shifted absorption maximum (462 nm) than P3HT, narrower electrochemical HOMO−LUMO gap (2.21 eV) and better solubility relative to P3HS.
In brief, our results provide an economical and convenient method for the direct C−H bond arylation polymerization of thiophene-selenophene alternating copolymer. It is envisaged that the employed methodology in this study can be further applied to synthesis of other alternating copolymers such as thiophene-tellurophene andselenophene-tellurophene alternating copolymers.
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Yu-Cheng, Liu, and 劉祐誠. "Synthesis, Characterization and Morphology of Block Copolymers Poly(3-hexylthiophene)-b-Poly(3-thiophene hexylacetate)." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/19361912772416664781.
Full textAbstract:
碩士<br>國立臺灣大學<br>高分子科學與工程學研究所<br>99<br>The synthesis, characterization and morphology study of copolymers of poly(3-hexylthiophene) (P3HT) and poly(3-thiophene hexylacetate) (P3THA) are performed in this thesis. By using GRIM method, polymers with high regioregularity, narrow polydispersity and controlled molecular weight can be obtained. From the optoelectronic properties characterization, the ester-functionalized P3THA shows a blue-shift UV-Vis spectrum and lower HOMO as compared to P3HT. These results are contributed to the bulky and the electron-withdrawing ester group which decrease the conjugated length. The amount of blue shift is directly proportional to the amount of P3THA in the block copolymer. From the CV measurements, each respective HOMO and LUMO is observed in each block segment of block copolymer which does not present in the random copolymers. The thermal and phase behaviors of the block copolymers were investigated by DSC, WAXS, GIWAXS and AFM. The crystalline morphology of copolymers is dependent on the block compositions of P3HT-b-P3THA. Phase separation is observed as the P3HT block higher than 50% molar ratio. When the molar ratio of P3THA is larger than 80%, the cocrystalline structure is observed. Thus, the crystalline morphology can be tuned by changing the block copolymer compositions. The results are useful for the design and fabrication of nanostructured conducting polymers.
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Chen, Yin Han, and 陳胤涵. "Thermal degradation of Poly(3-hydroxybutyrate)." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/46859585575586089115.
Full textAbstract:
碩士<br>高苑科技大學<br>高分子環保材料研究所<br>96<br>In this study, the thermal degradation behaviors of poly(3-hydroxy- butyric acid; PHB) were investigated at three heating rates and there various gases conditions as used by the thermogravimetry analyzer. The decomposition kinetic parameters i.e. order parameter, activation energy and pre-exponential factor of thermal decomposition were evaluated by using four analytical methods.
The experimental results showed that the retention time required for the PHB to a given temperature is longer for the lower heating rate. This would generally result in a higher conversion. Thus, the residual mass curve with a lower heating rate is to the left of that with a higher heating rate. According to Flynn-Wall analytical method, the activation energies of dynamic heating of PHB were 169.4, 123.1 and 82.0 kJ/mole under air, oxygen and nitrogen, respectively.
The activation energies for the overall thermal decomposition of PHB under nitrogen were evaluated by using Flynn-Wall, Maximum Decomposition Rate, Non-isothermal Condition and Multiple Regression analytical methods were 82.0, 99.0, 294.9 and 287.0 kJ/mole, respectively. Moreover, it was found that the Multiple Regression analytical method can very effectively evaluate the decomposition kinetic parameters of PHB very well by using experiment data from single heating rate of TGA.
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Li, Jui-Liang, and 李瑞亮. "Preparation and Properties of poly(3-hexylthiophene-co-N-3-hydroxypropyl)pyrrole." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/14644063694952747065.
Full textAbstract:
碩士<br>中原大學<br>化學研究所<br>95<br>In this research, the derivative of pyrrole, N-(3-hydroxypropyl) pyrrole (HPPY) has been synthesized and identified by 1H-NMR, 13C-NMR, FT-IR, UV-vis and GC-Mass spectroscopies.The homopolymers of poly(3-hexylthiophene) (P3HT) and poly N-(3-hydroxypropyl)pyrrole (PHP) and their copolymer poly(3-hexylthiophene-co-N-3-hydroxy)pyrrole have been prepared by electrochemical polymerization on the ITO glass. The electrochromic properties as-prepared copolymer coated ITO glass was innestigated by spectrum electrochemistry studies. The as-prepared copolymer was characterized by Fouier Transform Infrared (FT-IR) and Element analysis (EA). Effect of copolymer composition on the thermal stability, optical properties, electrochemistry, crystallinity. and surface morphology was evaluated by thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC),UV-Uisible absorption spectroscopy, cyclic voltaminetry (CV) studies,powder X-ray diffraction (XRD)pattern and scanning electron microscopy(SEM).
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Lan, Chin-Hung, and 藍慶鴻. "The phase separation behavior of poly(3-hydroxybutyrate-3-hydroxyhexanote)/poly(L-lactic acid) in blended electrospun fibers." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/27064042527918680251.
Full textAbstract:
碩士<br>元智大學<br>化學工程與材料科學學系<br>98<br>Electrospun fibrous membranes and cast membranes with the blends of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx)/poly(L-lactic acid) (PLLA) in various compositions were fabricated. The aim of this study was to make comparison of those membranes and identify the chain packing and phase behaviors in the cast and electrospun membranes with a blend of two crystallizable bio-polyesters. Some characteristic effects of electrospinning, such as the fast solvent evaporation, stress on the fibers due to electric field, and fiber size limitation, could result in the differences in chain packing, phase separation, partially mixed amorphous region, and limited crystallinity of the blends of PHBHHx/PLLA. The thermal properties were observed by differential scanning calorimetry (DSC), and the crystalline behaviors were characterized by wild-angle X-ray scattering (WAXS), and small-angle X-ray scattering (SAXS). The phase separation behavior in the blends was confirmed by using field emission scanning electron microscopy (FESEM) after an etching treatment. According to those results, a model of the chain packing in electrospun fibers of PHBHHx/PLLA blends could be constructed.
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Chan, Mei-Jui, and 詹美瑞. "The Reactions of Conducting Poly(3-alkylthiophene)." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/51341785548343477424.
Full textAbstract:
碩士<br>國立中央大學<br>化學系<br>86<br>Abstract The room temperature
stability of doped conducting poly(3-alkylthiophene),P3AT, films
with side chain numbers from 6 to 18 was studied. The UV/
Vis/ NIR absorption spectra were used to monitor the dedoping
process and calculate the dedoping rate. We found that dedoping
rate of poly(3-alkylthiophene) increases as the length of the
chain side increases. This result is consistent with the "
thermal undoping" which is attributed to the steric hindrance of
the long flexible side chains, which kick out the dopants.
Therefore, P3AT with longer alkyl side chain shows higher
dedoping rate. The stability of the polymer was also
dramatically influenced by the nature and stability of the
counteranions which were introduced into the polymer during
doping. P3ATs doped with AuCl3 were found to be more stable
than those doped with FeCl3. The mechanism of dedoping
reaction, derived from UV/Vis/NIR and ESR studies, can be
rationalized as bipolaronic states were first reduced to
polaronic states, polaronic states were then reduced to neutral
form. During dedoping , counteranion reacts with water to
produce small molecules, such as HCl, which diffuses out of the
polymer films and destroy the surface morphology of the films.
Moreover, some new polyalkylthiophenes derivatives,
functionalized with different side chains, were successfully
synthesized. The effects of the side chain on the stability of
doped polymer can be studied further in the future.
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Chang, Su-Chen, and 張素禎. "Surface modified poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) membranes for the biomedical applications." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/79146973233770302625.
Full textAbstract:
碩士<br>元智大學<br>化學工程與材料科學學系<br>98<br>The purpose of this study is to evaluate the properties of modified electrospun poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) membranes for biomedical applications. Induced-grafting polymerization of poly(acrylic acid) (PAA) was performed on the surface of the membranes with two kinds of surface pre-treatment: atmospheric-pressure plasma or ozone treatments. Biomacromolecules, such as collagen and hyaluronic acid, were immobilized onto the acid sites provided by PAA on the membrane surface with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as the coupling agent. The results of water-contact angle measurement and the surface morphology observation of membranes indicated that membranes had good wettability and were rough due to the grafting of PAA and immobilization of bio-macromolecules. Via electron spectroscopy for chemical analysis (ESCA) and attenuated total refection-Fourier transforms infrared spectroscopy (ATR-FTIR), it was found that the grafting density of PAA on the electrospun membranes was higher than that on the flat membrane (reference) prepared by compression-molding method. In the in vitro test of 3T3 fibroblast cell culture, the modified membranes showed higher viability and better adhesion than the unmodified ones. Due to the higher surface roughness, the in vivo degradation and absorption rate of modified electrospun membrane were largely enhanced. Thus, those modified electrospun PHBHHx membranes have potential to be used for biomedical applications.
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Yen, Wei-Che, and 顏唯哲. "Synthesis and characterization of Poly (3-hexylthiophene)-b-Poly (2-vinylpyridine)." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/18714367947107446636.
Full textAbstract:
碩士<br>國立臺灣大學<br>高分子科學與工程學研究所<br>93<br>To achieve high efficient organic photovoltaics, we propose to use self-assemble highly ordered block-copolymer as active layer to facilitate high charge carrier transport rate. In this study, we used anionic polymerization to synthesize block-copolymer poly(3-hexylthiophene)-b-poly(2-vinylpyridine)(P3HT-b-P2VP) with two compositions, 1: 2and 1: 49 (weight ratio). Their properties were studied by UV-vis, PL, TGA and TEM and compared them with pure P3HT and blend of P3HT-P2VP. In UV-vis and PL spectra, copolymers showed a blue-shift as compared with pure P3HT or blend. A red-shift was observed due to the aggregation of P3HT when a poor solvent, methanol, was added into pure P3HT or blend dissolved in THF. However, the optical spectra of block-copolymer did not change when they were dissolved either in tetrahydrofuran (THF) or methanol. The chemical bond between P3HT and P2VP in the copolymer has retarded the aggregation of P3HT in poor solvent. The decomposition temperatu of copolymer was greatly improved as compared with the neat P2VP, even with only a small amount of 2wt％ P3HT, from 352℃ to 381℃. This copolymer containg 2wt％ P3HT exhibitsa spherical morphology. In conclusion, we have synthesized P3HT-b-P2VP copolymer which will be used in photovoltaics.
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Chan, Hsuan-Yun, and 詹軒昀. "Production and characterization of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) by Bacillus sp. strains." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/47567882380508918774.
Full textAbstract:
碩士<br>元智大學<br>生物科技與工程研究所<br>97<br>Polyhydroxylalkanoates (PHA) are biodegradable polyesters that are accumulated in various microorganisms as intracellular carbon and energy storage material under nutrient-limited conditions. This study aimed to screen better production strains in order to obtain more efficient production of Polyhydroxylalkanoates from Bacillus sp. YW1, Bacillus sp. YW2 and Bacillus sp. YW3. This studies shown that these strains could be improved to grow and further synthesize PHB using various carbon sources. This work also suggests that the bacterial growth could be improved which the medium contain various organic acids. On the other hand, these strains could accumulate PHA when adding tryptone in media. A semi-synthesized medium (LBS medium) was developed for this study which could be able to support the growth of this Bacillus sp. YW1 and Bacillus sp.YW2 with 10 g/L PHB production and PHB content over 30%, respectively.
Temperature, pH and agitation rate are common environmental factors that play a crucial role in cell growth and PHB production. The optimal culture condition 30℃, pH 7, 200 rpm was used as the standard experimental condition. From this work, we found that the strains Bacillus sp. YW1 and YW2 could be induced to accumulate PHV over 12 %. PHA in the cell were purified primarily via different methods. The chemical structure and molecular masses of the purified PHA product were confirmed by nuclear magnetic resonance (1H-NMR & 13C-NMR) spectrometer and Gas Chromatography-Mass spectrometry (GC-MS), respectively. The property of the PHAs produced by Bacillus sp. strains isolated in this study was in consistent with the standard purchased from Sigma Co., indicating that Bacillus sp. strains are PHBV-synthesizing strain. Further analysis indicated that the PHV mole% of YW1 and YW2 strains were around 30%. According to analysis of GPC, the average Molecule weight was Mw=300,000 to 400,000; the strains YW1’s PDI was 4.71 and YW2’s PDI was 2.62. Besides, the data of TGA illustrated that PHBV has stable heat property. Moreover, the PHBV may be half-crystal polymer using DSC.
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Yeh, Cheng Yang, and 葉政洋. "Synthesis and Optoelectronic Properties of Alternative Copolymer Poly(3-hexylthiophene)-alt-Polythiophene and Random Copolymer Poly(3-hexylthiophene)-ram-Polythiophene." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/31240488834769161796.
Full textAbstract:
碩士<br>國立中正大學<br>化學工程研究所<br>99<br>We synthesize the alternative copolymer P3HT-alt-PT by Suzuki coupling reaction and random copolymer P3HT-ram-PT by Modified Grignard Metathesis(GRIM), comparing the advantages and the disadvantage of these two polymers, and finally we use some equipment to identify their characterization. LC/MS, 1H-NMR and FTIR can show the structure; TGA can show the temperature of decompose Td; DSC can show the glass transition temperature Tg and the melting point Tm; UV-Vis can show the absorption wavelength range of the visible light; PL can show the wavelength range of the fluorescence emitting; CV can show the HOMO, LUMO and band gap. Finally, these two polymers are used as the semi-conducting layer for the solar cell, and then we use the Oriel® Sol3A TM Class AAA Solar Simulators to identify the efficiency and the other relative characterization, expecting that they can be applied for the solar cell well.
Key words: Suzuki, Grignard, efficiency, solar cell
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Hsu, Jen-Che, та 許人哲. "Crystallization Behavior and Morphological Structure of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) - Poly(ε-caprolactone) Block Copolymers Under Isothermal Condition". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/56977828281621170815.
Full textAbstract:
碩士<br>逢甲大學<br>纖維與複合材料學系<br>100<br>This study focused on the morphology and melting behaviors of copolyester, which were synthesized from Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Poly(ε-caprolactone) with 60 weight percent of PCL. The melting behaviors were studied by a differential scanning calorimeter (DSC). The conformation were investigated by In-situ Fourier transform infrared spectrometer (In-situ FTIR) The crystal morphology were observed by using hot stage polarizing microscope (HSPM). The morphological structure were probed by small angle x-ray scattering (SAXS).
DSC showed that the melting enthalpy of PCL block decreased with the increase of temperature under isothermal conditions. When the temperature was over 45 ℃, the melting peak disappeared. FTIR showed that PHBV crystallized first at 60 ℃ and PCL crystals happened later at 36 °C from the melt. It could be concluded that PHBV crystallized at higher temperature and PCL crystallized at lower temperature. Based on HSPM and SAXS results, It showed that PCL block might exist in the confinement of PHBV lamellae at 35 ℃. When the temperature increased to 80 ℃, the long period increased with the interlamellae of melted PCL. The structure formed a lamellar morphology with crystalline and amorphous layers.
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Lee, Tai-chun, and 李岱軍. "Conformation Induced Molecular Aggregation in Poly(3-hexylthiophene)." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/54207782765945143457.
Full textAbstract:
碩士<br>輔仁大學<br>化學系<br>98<br>In this research, we’d like to study the morphology of P3HT in
solution by controlling spin rate in solution state and also its morphology
in films. UV-Vis and PL were used to monitor the state of aggregation
under different shear force. Viscosity measurements were conducted to
elucidate molecular conformation of P3HT in solution and to explain the
results from UV-Vis and X-ray measurements.
We found morphology of films prepared by aggregation of P3HT
itself in solution was different from that prepared by extra shear force.
Aggregation of P3HT itself in solution was destroyed during the film
formation by spin-coating process. Packing of P3HT by extra shear force
was maintained during the spin-coating process because shear force
pushed the P3HT molecules in helical form to pack together tightly furing
the stirring process. The results were different by using different solvents
and they are related to the conformation of P3HT in solution.
With this concept of organic solar cells can be used to process the
above. We can create without annealing can produce highly ordered
P3HT in close gatherings of activity layer, in order to save resources in
the production of batteries and costs.
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Ying-HsuanChou and 周映暶. "Lamellar Assembly in Ring-Banded Spherulitic Morphology of Biodegradable Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)Interacting with Amorphous Poly(vinyl acetate)." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/38027604164273833842.
Full textAbstract:
碩士<br>國立成功大學<br>化學工程學系碩博士班<br>98<br>Polarized-light optical microscopy (POM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), atomic force microscopy (AFM), and small-angle X-ray scattering (SAXS) techniques were used to probe the phase behavior and crystalline morphology in blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with poly(vinyl acetate) (PVAc). DSC thermal analysis and OM characterization proved that PHBV was miscible with PVAc. A small negative value of the interaction parameters (χ12= -0.32 for PHBV/PVAc blend) was obtained with the melting-point depression method. By compared with the growth rate of neat PHBV at crystallization temperature 60~100oC, those of PHBV in blends decrease with increasing PVAc contents. In addition, the growth rates of PHBV in blends of all compositions show a maximum value with respect to crystallization temperature (Tc), while Tc at which the maximum growth rate occurs is dependent on blend composition. Neat PHBV shows ring-banded spherulites at Tc = 60~110oC. However, the ring-banded patterns of PHBV in PHBV/PVAc blends crystallized at the same Tc become regular and the inter-ring spacing decreases with increasing PVAc contents. In addition, ringed textures of PHBV spherulites in blends are also observed in the fracture surface of bulk form samples. The AFM characterizations on the ring-banded spherulite of blend show that the ridge and valley regions of ring bands consist of edge-on and flat-on lamellae, respectively. A solvent-etching method was used to investigate the ring-banded spherulites of PHBV. The ridge bands of PHBV spherulites in un-etched and solvent-etched samples correspond to the bright and dark bands, respectively, under optical microscopy (OM) observation. The maximum melting temperature (Tmax) affects the morphology of the ring-banded spherulites. The spherulites of PHBV and PHBV/PVAc blends become larger after melting at higher Tmax, indicative of a decrease in nucleation density. Upon melting at a lower Tmax, the thickness of crystalline phase is thicker and PVAc is more easily located in interlamellar region compared to those melted at a higher Tmax.
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Chun-NingWu and 吳純寧. "Lamellae and Assembly in Spherulitic Morphology of Poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) in Presence of Poly(trimethylene adipate)." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/97230975480606878068.
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