Cordões de sisal como reforço em compósitos de matriz poliéster.

Abstract

In this effects of different surface treatments on sisal twines employed in the development of unidirectional continuous reinforced polyester composites were investigated. The composites were subjected to both pos-cure and hot water immersion conditions and their mechanical properties were determined. The surface treatments on the sisal twines in general reduced their tensile strength and increased their elastic moduli. The surface treatments increased the composite's tensile strength which is taken as an indication of better interfacial adhesion. Pos-cure caused a reduction on tensile strength and modulus of the surface modified reinforced composites. Hot water immersion (100°C for 2h) had a similar effect on the composite's properties except that, in this case, the changes were more drastic. Composites surface modified with poliol deformed greatly and did not allow tensile testing to be performed. Flexural strength of pos-cured composites suffered a 30% reduction, except for those modified with poliol where a slight increase in this property was observed. Pos-cure also reduced the composite's impact properties and this effect was more severe for the composites in which reinforcement was surface modified with urethane. The inverse behaviour was observed with poliol modified composites.