Influência de Tratamentos Superficiais em Partículas Lignocelulósicas da Casca do Café para Aplicação em Biocompósitos de Poliuretano Vegetal

Detalhes bibliográficos
Ano de defesa: 2021
Autor(a) principal: Gonçalves, Bárbara Maria Mateus
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal do Espírito Santo
BR
Mestrado em Engenharia Química
Centro de Ciências Agrárias e Engenharias
UFES
Programa de Pós-Graduação em Engenharia Química
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://repositorio.ufes.br/handle/10/15292
Resumo: Vegetable fibers have been extensively investigated and applied in polymeric biocomposites, mainly with the objective of improving their mechanical and thermal properties. However, when applied as reinforcement, these materials of a hydrophilic nature present problems of adhesion to polymeric matrices which, in turn, are more hydrophobic. In the present work, the effectiveness of three surface treatments applied to coffee husk residues was evaluated in order to improve the performance of castor oil-based polyurethane biocomposites, namely: i-chemical treatments with sodium hydroxide solutions , ii- hydrothermal under high temperature and pressure and iiibiological with solid state fermentation by the fungus Phanerochaete chrysosporium. In the results of chemical characterization, FTIR and SEM were observed the reduction of amorphous compounds for all methods and conditions tested, with emphasis on the treatments HYDRO 30 and NaOH 5 that presented anchorage points for the loads on their surfaces. The best mechanical performance was verified for biocomposites prepared with 20% of particles treated by the HYDRO 30 treatment. With gains of 65% in tensile strength compared to biocomposites prepared with the same percentage of fresh coffee husk, and 20% in value of the Elasticity Module in relation to polyurethane. In SEM analysis it was observed that these better particles adhered to the matrix. Furthermore, these biocomposites were the ones with the lowest water absorption content, 0.75%. Thus, the results obtained in this work indicate that the hydrothermal treatment presents itself as an ecological alternative to improve the particle/matrix interaction.