Miscibility and tensile properties of poly (β-hydroxybutyrate)–cellulose propionate blends

Maekawa, Masako; Pearce, R.; Marchessault, R. H.; Manley, R. St. John

doi:10.1016/s0032-3861(98)00359-0

Cited by 35 publications

(22 citation statements)

References 28 publications

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“…The temperature needed for erasing of crystal memory, 192 °C, is 16 °C higher than the peak of fusion of apparent crystal structure as registered by DSC at a rate of at °C for 1-5 minutes) are sufficient for destroying the previous thermal history and avoid self-seeding [33][34][35][36] should be seen in this view.…”

Section: Discussionmentioning

confidence: 98%

Optimization of melting conditions for the analysis of crystallization kinetics of poly(3-hydroxybutyrate)

2009

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Studies of kinetics of polymer crystallization are generally performed by heating the material above the melting point, in order to erase previous thermal and mechanical history, followed by rapid cooling to the desired crystallization temperature or by cooling at a constant rate. For poly(3-hydroxybutyrate) this procedure implies some degradation of the polymer chain, which starts below the onset of melting. In this article the effects of melting conditions on the subsequent crystallization kinetics are discussed. It is shown that in order to sufficiently cancel memories of previous crystalline order of the analyzed PHB, it is necessary to bring the material at a temperature higher than 192 °C. Thermal treatments conducted at lower temperatures are not sufficient to destroy all solid aggregates, and crystallization of PHB has an anticipated onset of crystallization due to nucleation occurring via self-seeding. The chain degradation attained upon exposure at high temperatures has much lesser influence on crystallization kinetics than incomplete melting, with some effects detectable on the spherulitic morphology and on the final degree of crystallinity.Brought to you by | Boston University Library Mugar Memorial Library Authenticated Download Date | 8/7/15 12:16 PM

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Section: Discussionmentioning

confidence: 98%

Optimization of melting conditions for the analysis of crystallization kinetics of poly(3-hydroxybutyrate)

2009

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“…Maekawa and coworkers reported that blends of PHB and cellulose propionate were completely miscible since they had a single glass transition, a depression in the equilibrium melting temperature of PHB and a decrease in spherulitic growth rate of the PHB component. Also tensile strength was better for the blend of PHB/cellulose propionate than for PHB only (250). However, not all blends are compatible.…”

Section: Applications Of Phamentioning

confidence: 90%

Bacterial polyhydroxyalkanoates-eco-friendly next generation plastic: Production, biocompatibility, biodegradation, physical properties and applications

Muhammadi

Shabina

Afzal

et al. 2015

Green Chemistry Letters and Reviews

270

139

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Polyhydroxyalkanoates (PHAs) are intracellular aliphatic polyesters synthesized as energy reserves, in the form of water-insoluble, nano-sized discrete and optically dense granules in cytoplasm by a diverse bacteria and some archae under conditions of limiting nutrients in the presence of excess carbon source. Bacteria synthesize different PHAs from coenzyme A thioesters of respective hydroxyalkanoic acid, and degrade intracellularly for reuse and extracellularly in natural environments by other microorganisms. In vivo, PHAs exist as amorphous mobile liquid and water-insoluble inclusions but in vitro, exhibit material and mechanical properties, ranging from stiff and brittle crystalline to elastomeric and molding, similar to petrochemical thermoplastics. Further, they are hydrophobic, isotactic, biocompatible and exhibit piezoelectric properties. But as commodity plastics their applications are limited by high production cost, low yield, in vivo degradation, complexity of technology and difficulty of extraction. Therefore, to replace the conventional plastic with PHAs, it is prerequisite to standardize the PHA production systems.

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“…[85][86][87][88][89][90][91][92][93] Estudos conduzidos em tais blendas através de DMA e DSC indicam que tanto o PHB como seus copolímeros (PHB-co-HV) formam blendas miscíveis com os derivados de celulose. [85][86][87][88][89][90][91][92][93] Para teores acima de 50% em massa de PHB observa-se uma queda na temperatura de fusão, com o aumento na quantidade de celulose, indicando a miscibilidade do sistema. Por outro lado, para teores de PHB inferiores a 50% em massa, a cristalização do PHB é impedida, sendo obtidas blendas amorfas.…”

Section: Blendas De Phb E éSteres De Celuloseunclassified

Blendas de PHB e seus copolímeros: miscibilidade e compatibilidade

Quental¹,

Carvalho²,

Tada³

et al. 2010

Quím. Nova

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Recebido em 12/5/09; aceito em 29/7/09; publicado na web em 8/1/10 BLENDS OF PHB AND ITS COPOLYMERS: MISCIBILITY AND COMPATIBILITY. Poly(hydroxybutyrate) and its copolymers are linear polyesters behaving as conventional thermoplastic materials. However, they are totally biodegradable and produced by a wide variety of bacteria from renewable sources. Some properties and high production cost are still preventing future applications. In an attempt to improve the properties and to reduce cost blending PHB with others polymeric materials is one of the most efficient method. In this paper, miscibility, compatibility, morphological and mechanical aspects of PHB blends will be reviewed. An extensive revision over twenty last years was realized about works of blends based on PHB and its copolymers.Keywords: blends; PHB; miscibility. INTRODUÇÃO Poli(hidroxibutirato) -PHBO PHB e seus copolímeros são produzidos naturalmente por bactérias a partir de fontes renováveis de energia, e são biodegradados por uma enorme quantidade de bactérias e fungos presentes na natureza. 1,2 No Brasil, a produção de PHB foi desenvolvida por uma joint venture entre a Copersucar (Cooperativa dos Produtores de Canade-açúcar do Estado de São Paulo), o IPT (Instituto de Pesquisas Tecnológicas) e pelo ICB (Instituto de Ciências Biomédicas da USP).3,4 A produção de PHB, encontrou condições excepcionalmente favoráveis no Brasil devido às características da indústria de açúcar e álcool, bastante desenvolvida durante o programa PROALCOOL. A disposição de açúcar a baixos preços e grandes quantidades, que é utilizado como substrato para o crescimento das bactérias do PHB, é uma das principais características que favorecem a produção desse polímero.De 1995 a 2000, a primeira produção em planta piloto do PHB no Brasil, utilizando o processo Copersucar-IPT-ICB, foi realizada na usina de açúcar e álcool Usina da Pedra. Os principais objetivos dessa planta piloto foram testar a viabilidade do processo, desenvolvê-lo e realizar uma avaliação econômica do custo de produção de PHB. 4 Em 2000, a produção comercial de PHB se iniciou com a criação da empresa PHB Industrial, em Serrana, próxima à Usina da Pedra. 4 A produção de PHB pela PHB Industrial é a única produção industrial de PHB a partir de cana-de-açúcar e integrada em usina sucroalcooleira. Essa empresa opera desde 2005 com uma planta de capacidade máxima de 60 toneladas de PHB por ano. "Enquanto na Europa, o PHB é produzido a US$10-20,00/kg, no Brasil esses custos estão entre US$2,5-5,00/kg (...)".3 No entanto, esse preço ainda é muito superior aos preços dos polímeros sintéticos da indústria petroquímica, o que desestimula a ampla comercialização do PHB.A biodegradabilidade não pode ser o único atrativo no PHB ou em qualquer polímero biodegradável. Para ser aceito em larga escala, estes polímeros têm de possuir os atrativos dos termoplásticos convencionais como: (i) suprir a demanda do mercado, ou seja, ser produzido em grande quantidade; (ii) correta compostagem para preservar a sua biodegradação; (iii)...

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Miscibility and tensile properties of poly (β-hydroxybutyrate)–cellulose propionate blends

Cited by 35 publications

References 28 publications

Optimization of melting conditions for the analysis of crystallization kinetics of poly(3-hydroxybutyrate)

Optimization of melting conditions for the analysis of crystallization kinetics of poly(3-hydroxybutyrate)

Bacterial polyhydroxyalkanoates-eco-friendly next generation plastic: Production, biocompatibility, biodegradation, physical properties and applications

Blendas de PHB e seus copolímeros: miscibilidade e compatibilidade

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