Influ?ancia do tratamento qu?-mico da fibra de bananeira em comp?3sitos de poli(etileno-co-acetato de vinila) com e sem agente de expans?￡o

摘要

In this work the influence of alkaline treatment on banana fiber (BF) and its use as reinforcement agent in expanded composites of poly(ethylene-co-vinyl acetate) - EVA were assessed. The mixing process for the composite was performed in an open roll mill, with composites being then shaped and expanded in a thermal press using variable volume molds. The composites were evaluated as for their mechanical, thermal and morphological properties. The results indicate that the alkali treatment promotes the extraction of less stable BF components such as lignin, hemicellulose, waxes and low molecular weight oils. The use of BF in the composites imparts reduction in mechanical properties of tensile and tear strength compared to neat EVA, owing to the moderate properties of the polymer-fiber interface. In expanded composites, the mechanical properties decreased with the reduction in density due to a higher amount of void spaces within the composites. However, the specific mechanical properties of tear strength showed improved results with 10 phr BF in all molds.