Estudo da utilização de radiação UV como ferramenta para modificação da superfície de filmes de PHBV
Data
2020-10-09
Autores
Campos, Clara Alves 
Orientadores
Lemes, Ana Paula
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O acúmulo de lixo gerado pelo consumo excessivo de plástico é motivo de preocupação, além de encadear graves problemas ao meio ambiente, vida terrestre e vida marinha. Devido a isso, surge- se a necessidade de alternativas que sejam sustentáveis e que não agridem o meio ambiente. Com isso, este trabalho teve por objetivo estudar o efeito da radiação ultravioleta (UV) em amostras de um polímero biodegradável, o PHBV, para que este possa se aderir à celulose nanofibrilada, CNF, constituindo um filme multicamada com melhores propriedades de resistência mecânica, barreira ao oxigênio e biodegradável. Por ser constituído de materiais naturais, este filme pode ser utilizado em embalagens plásticas e substituindo as convencionais que levam maiores tempos de degradação. Para este estudo, amostras de filmes de PHBV foram submetidos à radiação UV por 2h, 4h, 6h, 8h e 10h a fim de obter o melhor tempo de exposição. Após radiação UV, estes foram caracterizados por FTIR, onde a partir dos resultados do ensaio foi calculado o índice de carbonila, obtendo o valor de 50,7 para a mostra de 2h e 51,5 para a amostra de 4h. Este aumento pode significar que houve uma incorporação de grupos carbonilas na amostra, deixando a amostra mais hidrofílica. Os resultados das outras amostras foram desconsiderados, por algum erro, que pode ter sido ocasionado pelas condições de ambiente ou pela amostra se mostrar rugosa. O ângulo de contato nos permitiu concluir que de fato as amostras se tornam mais hidrofílicas com a radiação UV, pois todas as amostras apresentaram ângulo de contato menor em relação ao PHBV sem exposição. O que se esperava era que com maiores tempos de exposição, menor o ângulo de contato, porém não foi o que ocorreu. O que é possível afirmar que com apenas 2h de exposição já foi suficiente para alterar a superfície e o caráter hidrofóbico do PHBV. O TGA seria para analisar se a curva de decomposição térmica do PHBV seria modificada por meio da radiação UV, porém não foi possível realizar este ensaio e foi realizado um estudo teórico. Por fim, a microscopia óptica (MO) seria a análise da aderência do filme multicamada após prensagem, porém não foi possível realizar o ensaio e foi realizado um estudo teórico. Sendo assim, a modificação da superfície do PHBV por radiação UV constitui uma alternativa para este polímero se tornar semelhante à CNF, permitindo a aderência destes dois materiais, formando um filme multicamada, com boas propriedades para ser aplicado em embalagens plásticas biodegradáveis.
The huge amount of garbage accumulated, due excessive consumption of plastic, is a global concerning. This fact is also causing serious problems to the environment, and terrestrial and marine life. As result of that, there is a need for alternative materials that are sustainable and not harmful for the environment. Therefore, this work aimed to study the effect of UV radiation on samples of a biodegradable polymer, PHBV, being possible to adhere into the nanofibrilated cellulose, NFC, constituting a multilayer film with better properties, such as mechanical resistance, oxygen barrier and biodegradable. And as it consists of natural materials, it can be used in plastic packaging, replacing conventional ones that take longer degradation times. For this study, samples of PHBV films were submitted to UV radiation for 2h, 4h, 6h, 8h and 10h in order to obtain the best exposure time. After UV radiation, they were characterized by FTIR, where the carbonyl index was calculated from the test results, obtaining the value of 50 for the 2h sample and 51 for the 4h sample. This increase possible mean that there was an incorporation of carbonyl groups in the sample, leaving it more hydrophilic. The results of certain number of samples were disregarded, due to environmental conditions or the sample is rough. The contact angle allowed us to conclude that in fact the samples become more hydrophilic with UV radiation, since all samples had a smaller contact angle in relation to PHBV without exposure. What was expected is that longer exposure, will result in lower contact angle, but that not happened. However, it was possible to observe that with only two hours of exposure, it was possible to change the surface and the hydrophobic character of PHBV. The TGA would be used on this work to analyze whether the PHBV thermal decomposition curve would be modified by means of UV radiation, although the test was not performed. Finally, optical microscopy would be the analysis of the adhesion of the multilayer film after pressing, but it was not possible to do this analysis and a theoretical study was done. Thus, the modification of the PHBV surface by UV radiation is an alternative for this polymer to become similar to NFC, allowing the adhesion of these two materials, forming a multilayer film, with good properties to be applied in biodegradable plastic packaging.
The huge amount of garbage accumulated, due excessive consumption of plastic, is a global concerning. This fact is also causing serious problems to the environment, and terrestrial and marine life. As result of that, there is a need for alternative materials that are sustainable and not harmful for the environment. Therefore, this work aimed to study the effect of UV radiation on samples of a biodegradable polymer, PHBV, being possible to adhere into the nanofibrilated cellulose, NFC, constituting a multilayer film with better properties, such as mechanical resistance, oxygen barrier and biodegradable. And as it consists of natural materials, it can be used in plastic packaging, replacing conventional ones that take longer degradation times. For this study, samples of PHBV films were submitted to UV radiation for 2h, 4h, 6h, 8h and 10h in order to obtain the best exposure time. After UV radiation, they were characterized by FTIR, where the carbonyl index was calculated from the test results, obtaining the value of 50 for the 2h sample and 51 for the 4h sample. This increase possible mean that there was an incorporation of carbonyl groups in the sample, leaving it more hydrophilic. The results of certain number of samples were disregarded, due to environmental conditions or the sample is rough. The contact angle allowed us to conclude that in fact the samples become more hydrophilic with UV radiation, since all samples had a smaller contact angle in relation to PHBV without exposure. What was expected is that longer exposure, will result in lower contact angle, but that not happened. However, it was possible to observe that with only two hours of exposure, it was possible to change the surface and the hydrophobic character of PHBV. The TGA would be used on this work to analyze whether the PHBV thermal decomposition curve would be modified by means of UV radiation, although the test was not performed. Finally, optical microscopy would be the analysis of the adhesion of the multilayer film after pressing, but it was not possible to do this analysis and a theoretical study was done. Thus, the modification of the PHBV surface by UV radiation is an alternative for this polymer to become similar to NFC, allowing the adhesion of these two materials, forming a multilayer film, with good properties to be applied in biodegradable plastic packaging.
Descrição
Citação
C. A. Campos, “Estudo da utilização de radiação UV como ferramenta para modificação da superfície de filmes de PHBV,” São José dos Campos, 2020.