Obtenção e caracterização de filmes de PHB e de blendas de PHB com borracha natural
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Data
2008-02-25
Autores
Fuzari Junior, Gilberto de Campos [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Filmes de PHB puro e de blendas de PHB com borracha natural foram obtidos por prensagem a quente e por “casting” e foram avaliados segundo as propriedades morfológicas, estruturais, térmicas e mecânicas, além de sua suscetibilidade à biodegradação. As blendas mostraram-se imiscíveis. Verificou-se que o processamento e a presença de borracha provocaram mudanças na configuração cristalina do PHB. A presença de borracha aumentou o grau de cristalização do PHB. Filmes tratados termicamente entre 60 e 70oC, apresentaram menor grau de cristalinidade, os quais permanecem estáveis quando resfriados à temperatura ambiente. O processamento por prensagem garantiu certa estabilidade ao filme de PHB puro em relação à degradação isotérmica, por ocasionar a compactação das cadeias poliméricas, compactação essa que é influenciada pela presença de borracha. Para a degradação não isotérmica, um maior conteúdo de borracha elevou a temperatura de degradação efetiva. O aumento de borracha na blenda também ocasionou maior deformação das blendas, com decréscimo de rigidez. O processamento por prensagem garantiu uma maior deformação para filmes de PHB puro em relação ao processamento por casting, entretanto para blendas com grande quantidade de borracha o efeito mostrou-se contrário. Análises de biodegradação em solo mostraram um material potencialmente biodegradável, sendo que a presença de borracha não atrapalhou o ataque microbiano
Pure PHB films and blends of PHB and natural rubber (in films form), were obtained by hot pressing and by casting and its morphological, structural, thermal and mechanical properties were studied using appropriated techniques. The susceptibility to the biodegradation was also analyzed. The blends did not show miscibility and crystallization degree of PHB in the blend showed to be dependent of rubber content and also film processing. Lower degree of crystallization was observed on films treated in the temperature range of 60oC to 70oC. This crystallization remains stable when the temperature drops to room temperature. Pure PHB films obtained by hot pressing showed stability regards to the isothermal degradation due to the polymer chain compaction, which is influenced by the rubber inclusion. The temperature degradation was increased as the rubber content was increased. The increasing content of rubber in the blend films also provide higher deformation with decreasing of stiff. Pure PHB films obtained by hot pressing showed higher deformation then those obtained by casting. However, for blend films with high rubber content, the effect was observed in the other way around. Furthermore, biodegradation analyzes in soil showed that the material is biodegradable and the rubber inclusion does not disturb the microbial attack
Pure PHB films and blends of PHB and natural rubber (in films form), were obtained by hot pressing and by casting and its morphological, structural, thermal and mechanical properties were studied using appropriated techniques. The susceptibility to the biodegradation was also analyzed. The blends did not show miscibility and crystallization degree of PHB in the blend showed to be dependent of rubber content and also film processing. Lower degree of crystallization was observed on films treated in the temperature range of 60oC to 70oC. This crystallization remains stable when the temperature drops to room temperature. Pure PHB films obtained by hot pressing showed stability regards to the isothermal degradation due to the polymer chain compaction, which is influenced by the rubber inclusion. The temperature degradation was increased as the rubber content was increased. The increasing content of rubber in the blend films also provide higher deformation with decreasing of stiff. Pure PHB films obtained by hot pressing showed higher deformation then those obtained by casting. However, for blend films with high rubber content, the effect was observed in the other way around. Furthermore, biodegradation analyzes in soil showed that the material is biodegradable and the rubber inclusion does not disturb the microbial attack
Descrição
Palavras-chave
Biodegradação, PHB, Borracha natural, Blendas poliméricas
Como citar
FUZARI JUNIOR, Gilberto de Campos. Obtenção e caracterização de filmes de PHB e de blendas de PHB com borracha natural. 2008. 71 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Engenharia de Ilha Solteira, 2008.