Biodegradação de filmes de PHBV, PCL, PP e BLENDAS pela ação de microorganismos de solo
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Data
2009-04-30
Autores
Gonçalves, Suely Patricia Costa [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Neste trabalho, estudou-se a biodegradação dos filmes de PHB-V, PCL, PP e das blendas de PCL/PHB-V (4:1) e PP/PHB-V (4:1) em solo. Os filmes poliméricos foram preparados por compressão a quente e analisados através das análises de infravermelho com transformada de Fourier (FTIR), microscopia eletrônica de varredura (MEV), calorímetria exploratória diferencial (DSC), termogravimetria (TG) e difração de raio-X (DRX), para investigar os processos de biodegradação por um período de 120 dias. A atividade microbiana foi monitorada durante todo o período de experimento, bem como vários parâmetros: pH, temperatura, umidade, matéria orgânica, quantidade de CO2 e quantificação de microrganismos. Após os diferentes tempos do ensaio em solo, os filmes poliméricos apresentaram alterações quanto a sua estrutura molecular e morfologia em diferentes intensidades. Os processos de biodegradação observados nos diferentes filmes poliméricos, ocorreram via erosão superficial. O filme de PHB-V, foi o mais suscetível ao ataque microbiano, sendo completamente decomposto em 30 dias. O grau de cristalinidade de PHB-V permaneceu inalterado, pois a biodegradação ocorreu simultaneamente nas fases amorfa e cristalina. Para os filmes de PCL a biodegradação ocorreu tanto na fase amorfa como na interface do polímero. Os filmes de PP, após a biodegradação apresentaram uma ordenação na estrutura cristalina, denominada como “quemi-cristalização”. A biodegradação das blendas de PCL/PHB-V (4:1) e PP/PHB-V (4:1) ocorreu na interfase dos dois componentes da blenda, indicando que a imiscibilidade/morfologia são fatores que influenciam significativamente no processo de degradação.
In this works, we studied the biodegradation of the films of PHB-V, PCL, PP and the blends of PCL / PHB-V (4:1) and PP / PHB-V (4:1) in soil. The polymer films were prepared by melt-pressing and was evaluated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry (TGA) and X-ray diffraction (XRD), and investigated with respect to their microbial degradation in soil after 120 days. Microbial activity was monitored during the whole experiment, and various parameters: pH, temperature, moisture, organic matter, amount of CO2 and quantification of microorganisms. After different times of the test in soil, the polymer films showed changes in their molecular structure and morphology in different intensities. The processes of biodegradation observed in various polymer films, occurred via surface erosion. The film of PHB-V was the most susceptible to microbial attack and was completely decomposed in 30 days. The degree of crystallinity of PHB-V remained unchanged since the degradation occurred in both crystalline and amorphous phases. For films of PCL biodegradation occurred in both the amorphous phase as the interface of the polymer. The films of PP after biodegradation underwent an arrangement of the crystalline structure, known as chemi-crystallization. The biodegradation of the blends of PCL / PHB-V (4:1) and PP / PHB-V (4:1) occurred in the interphase of the two components of the blends, indicating that the immiscibility/morphology are factors that significantly influence the process of degradation.
In this works, we studied the biodegradation of the films of PHB-V, PCL, PP and the blends of PCL / PHB-V (4:1) and PP / PHB-V (4:1) in soil. The polymer films were prepared by melt-pressing and was evaluated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry (TGA) and X-ray diffraction (XRD), and investigated with respect to their microbial degradation in soil after 120 days. Microbial activity was monitored during the whole experiment, and various parameters: pH, temperature, moisture, organic matter, amount of CO2 and quantification of microorganisms. After different times of the test in soil, the polymer films showed changes in their molecular structure and morphology in different intensities. The processes of biodegradation observed in various polymer films, occurred via surface erosion. The film of PHB-V was the most susceptible to microbial attack and was completely decomposed in 30 days. The degree of crystallinity of PHB-V remained unchanged since the degradation occurred in both crystalline and amorphous phases. For films of PCL biodegradation occurred in both the amorphous phase as the interface of the polymer. The films of PP after biodegradation underwent an arrangement of the crystalline structure, known as chemi-crystallization. The biodegradation of the blends of PCL / PHB-V (4:1) and PP / PHB-V (4:1) occurred in the interphase of the two components of the blends, indicating that the immiscibility/morphology are factors that significantly influence the process of degradation.
Descrição
Palavras-chave
Polimeros, Biodegradação, Solos, Blenda, Biodegradation, Polymers, Blend, Soil
Como citar
GONÇALVES, Suely Patricia Costa. Biodegradação de filmes de PHBV, PCL, PP e BLENDAS pela ação de microorganismos de solo. 2009. 140 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2009.