Desenvolvimento e caracterização de compósitos de elastômero termoplástico reforçado com fibra de bananeira

• Ano de defesa: 2014
• Autor(a) principal: Barros, Renata Tamara Pereira de [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Sustentabilidade; Resíduo vegetal; Fibra de bananeira; Elastômero termoplástico; Compósitos
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=2102186; http://repositorio.unifesp.br/handle/11600/48947

The banana crop has been shown to be a potential source of fibers with good mechanical properties. In this work, residual banana fiber was used as reinforcement in composite materials with a thermoplastic elastomer matrix. In the usual methodology of fiber extraction from the pseudostem of banana, is generated lot of waste. In order to add value to this waste generated was evaluated an alternative methodology for obtaining the fibers using a larger amount of pseudostem. The class of polymers of thermoplastic elastomers (TPE's) have the advantage of not being able to count on crosslinking elastically deform, so behave as thermoplastics at high temperatures, and as elastomers (rubbers) at low temperatures. In order to enhance adhesion between fiber and matrix, both banana fibers (FB) obtained by the conventional extraction (FBA) and the alternative method (FBB) were subjected to treatment with alkaline solution (5% NaOH ( m / v)). The FBA and FBB fibers, raw and treated been incorporated into the thermoplastic elastomer of the SEBS type in the proportions of 2, 5 and 10% by weight of polymer resin. The composite TPE / FBB and TPE / FBA were processed in calender equipment. The characterizations of the composites were made by thermal analysis of differential scanning calorimetry (DSC), thermogravimetry and first derivative (TG / DTG), mechanical test with tensile test and obtained the maximum tensile stress, elastic modulus and elongation in tension maximum. In addition, fracture session micrographs were observed by scanning electron microscopy (SEM). The FB were also characterized by their chemical composition, crystallinity index (obtained by XRD), TG / DTG spectroscopy and Fourier transform infrared (FTIR). The characterization of the chemical composition of the fibers showed that FBA showed a larger fraction of the FBB cellulose and DRX tests have shown higher crystallinity compared to the FBA FBB. FTIR spectra showed the characteristic bands FBA are the same as those found in FBB. The analysis of FTIR, DSC and XRD showed that the alkaline treatment promoted the removal of the amorphous fraction (lignin and hemicellulose) FBA and FBB. The composites obtained with 2% to 5% FBA and FBB, processed and fresh, had a uniform mat, however, the composites made with 10% FBB presented is brittle, it is not possible to form a continuous blanket. The SEM micrographs in show little interaction between the fiber and matrix. The number of voids observed in the fracture surface is proportional to the percentage of incorporated fibers suggesting that there was the matrix fiber pullout during exercise. The tensile test showed superior performance of composites made with FBA. In these composites there was an increase of the maximum tensile stress. The low mechanical performance FBB can be attributed to the presence of extractives not fibrous (amorphous) in its composition, and the largest fraction of hemicellulose compared to the FBA. In general the thermal stability of the composites produced with FBA stood at intermediate temperature between the TPE and FBA, however after initiation of the degradation rate of degradation of the composite was higher than the pure PET blanket. The composites produced with 2 to 5% of FBA treated showed an improvement in thermal performance.