Estudo de fibras de folhas de abacaxis (gênero Ananas) e sua utilização em compósitos biodegradáveis com matriz de poli(ácido lático) (PLA)

Detalhes bibliográficos
Ano de defesa: 2014
Autor(a) principal: Sena Neto, Alfredo Rodrigues de
Orientador(a): Mattoso, Luiz Henrique Capparelli lattes
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de São Carlos
Programa de Pós-Graduação: Programa de Pós-Graduação em Ciência e Engenharia de Materiais - PPGCEM
Departamento: Não Informado pela instituição
País: BR
Palavras-chave em Português:
Área do conhecimento CNPq:
Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/731
Resumo: In this work natural fibers from new pineapple varieties were studied aiming at their application as mechanical reinforcement for green polymer composites. Eighteen varieties of pineapple leave fibers (PALFs) were then characterized in terms of their morphology, structural arrangement (cellulose crystallinity index (Ic) and microfibril angle), chemical composition (extractives, lignin, holocellulose, cellulose and hemicellulose contents), mechanical properties (tensile strength, elastic modulus and fracture strain) and thermal stability. The studied PALFs had low microfibril angles and high Ic. Their elastic modulus, tensile strength and degradation temperature onset ranged between 15GPa-86GPa, 212MPa-1309MPa, 240°C 272ºC, respectively. All these parameters enabled to nominate the eighteen PALFs as suitable reinforcements for polymers. Close relationships between cellulose, holocellulose and Ic values, and thermal and mechanical properties of PALFs were found out, what provided guidelines for direct selection and/or to support a genetic improvement program of the Ananas genus. An example of such a methodology was presented in this work. The fiber from the pineapple variety called "Potyra" was selected to produce biodegradable composites with poly(lactic acid) (PLA) through injection molding. The Potyra fibers were before hand treated with alkaline solution in order to improve their interfacial compatibility with PLA. The treated Potyra fibers-reinforced composite exhibited an increased elastic modulus from 1,9 GPa to 3,5GPa, tensile strength from 58,8 to 69,6MPa, and notched impact strength from 2,57kJ/m2 to 4,26kJ/m2 in comparison to the pure PLA matrix. The HDT of the PLA was also incremented by 10% due to the fiber incorporation. These findings confirmed the promising potential of Potyra fibers as reinforcements in green composite technologies.