Avaliação e caracterização de compósitos de matriz poliéster reforçadas com fibras de sisal (Agave Sisalana)

Abstract

This work presents results of mechanical characterization, the chemical evaluation sisal fibers at different treatment times, for use as reinforcement of polyester matrix composites. Sisal was slightly modified by an alkaline treatment of fibers known as mercerization. Plates were made of composites, these arranged in unidirectional polymer matrix. The concentration of NaOH in the fibers were kept at 3% and the treatment time varied: one hour, two hours and three hours. Both the fibers and untreated fibers which have undergone treatment were distributed in the polymeric matrix in longitudinal direction. All composites were prepared in the same weight of fiber mass (30 grams each) previously dried. Compression molding was used in all treated and untreated plates with NaOH, and the plates subjected to post-curing for 48 hours at 80 ° C. The bodies of the specimens were sawn by hand to achieve the flexural and impact tests in accordance with ASTM D 790-03 and ASTM D 256-04 respectively. Changes in surface morphology of the fibers were evaluated by Scanning Electron Microscopy (SEM). The composites without treatment showed better results in flexural strength than those who were treated. However, the composites were treated best results in impact resistance. Therefore, tests have shown that sisal fibers have great potential as reinforcement in polyester resin with satisfactory results in mechanical properties to fibers without treatment and after mercerization.