The fractionated crystallization phenomenon in poly(3-hydroxybutyrate)/poly(ethylene oxide) blends

Avella, Maurizio; Martuscelli, E.; Raimo, Maria

doi:10.1016/0032-3861(93)90396-r

Cited by 107 publications

(58 citation statements)

References 4 publications

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“…It was observed that the MMT exhibits a single 001 diffraction peak around 2y ¼ 7. 5 corresponding to an interlayer distance of 12.2 Å . This basal peak of the MMT was shifted to lower angles in the composite with CNa þ , regardless the clay content.…”

Section: Resultsmentioning

confidence: 99%

“…The main reaction involves chain scission, which results in a rapid decrease in molecular weight and further degradation to crotonic acid at high temperatures. 1,[5][6][7][8] Recently, the development of nanocomposites by incorporating nanoscaled fillers into a polymer matrix is believed to become a key technology on advanced composite materials. It is well-known that nanocomposites obtained by the addition of low percentages of clay to polymers exhibited an improvement in the properties such as, thermal and oxidative barrier when they were compared with traditional composites.…”

Section: Introductionmentioning

confidence: 99%

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Relationship between thermal properties, morphology, and crystallinity of nanocomposites based on polyhydroxybutyrate

D'amico

Manfredi

Cyras

2011

J of Applied Polymer Sci

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Polyhydroxybutyrate (PHB) has a significant instability at temperature close to the melting point. The aim of this work was to improve the thermal resistance of PHB by the addition of small amounts of two different types of clays: Cloisite. C15A has more hydrophobic character and interlayer distance than CNa þ . It was observed that the addition of the organically modified montmorillonite (MMT) increased by more than 15 C the thermal resistance of the PHB while the addition of CNa þ reduced it. This result was related to the different morphology of the final materials. The maximum in the degradation temperature of the nanocomposites with 4% of clay was in accordance with the maximum in the percentage of crystallinity. However, the interlayer gallery distance of the C15A was higher than the CNa þ in the PHB matrix, according to the better thermal stability of the C15A due to the higher barrier effect and the lower chain mobility. A slight increase in the Young modulus of the polymer was observed with the addition of C15A, due to the compatibility between the MMT and PHB. The calorimetric and microscopy results showed that clays did not accelerate the formation of PHB spherulites nucleus, but the lamellar velocity was accelerated.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Relationship between thermal properties, morphology, and crystallinity of nanocomposites based on polyhydroxybutyrate

D'amico

Manfredi

Cyras

2011

J of Applied Polymer Sci

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“…Testes de biodegradabilidade para as blendas de PHB/PEO indicaram que elas são totalmente biodegradáveis. [66][67][68][69][70] Apesar de vários estudos [66][67][68][69][70][71] ) tem sido utilizado. Zhao et al 72 estudaram blendas de PHB com PEO de alta massa molar (2.0 x 10 5 g mol -1 ) e verificaram que a massa molar do PEO é um importante fator que influencia na miscibilidade dessas blendas.…”

Section: Blendas De Phb Com Polímeros Biodegradáveis Phb/poli(óxido Dunclassified

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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“…Nevertheless, simultaneous crystallization is rare, and step crystallization is common. This holds particularly for blends where the melting point difference of the two components is large as, for example, in the systems poly (vinylidene fluoride)/ poly(1,4-butylene adipate) (PVDF/PBA), 23,24 poly (ethylene oxide)/polyhydroxybutyrate (PEO/PHB) [5][6][7] or, particularly, PC/PCL.…”

Section: Htc/ncc Systems: Crystallization Induced Composition Changesmentioning

confidence: 99%

Crystallization kinetical and morphological peculiarities in binary crystalline/crystalline polymer blends

Liu

Jungnickel

2007

J Polym Sci B Polym Phys

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A survey is presented on the crystallization kinetics and the morphology of miscible crystalline/crystalline polymer blends. There are only few corresponding systems. In them, however, a number of strange kinetic and structural phenomena can be observed: (i) spherulitic crystallization of the components side‐by‐side, (ii) “interpenetrating crystallization,” (iii) “interlocking spherulitic crystallization,” and (iv) “interfilling crystallization.” Cocrystallization is forbidden for crystallographic reasons. The blend partners grow instead in their own lamellar stacks, and mixed lamellar stacks are a seldom and questionable exception. They crystallize also usually stepwise and not simultaneously. Upon step crystallization, the crystallization of the second component is determined by its redistribution with crystallization of the former. Those composition inhomogeneities are an independent issue that arises also with the development of the morphology in crystalline/amorphous blends, and a corresponding survey is yielded, too. The blend poly (vinylidene fluoride)/poly‐β‐hydroxybutyrate is a convenient model system as it can show all of these morphological and kinetic features after suitable thermal treatment. Some of them are demonstrated in the present publication. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1917–1931, 2007

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The fractionated crystallization phenomenon in poly(3-hydroxybutyrate)/poly(ethylene oxide) blends

Cited by 107 publications

References 4 publications

Relationship between thermal properties, morphology, and crystallinity of nanocomposites based on polyhydroxybutyrate

Relationship between thermal properties, morphology, and crystallinity of nanocomposites based on polyhydroxybutyrate

Blendas de PHB e seus copolímeros: miscibilidade e compatibilidade

Crystallization kinetical and morphological peculiarities in binary crystalline/crystalline polymer blends

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