Resin–Sisal and wood flour composites made from unsaturated polyester thermosets

Abstract

Short fibers and wood flour were selected as fillers in the production of two types of unsaturated polyester composites (bisphenolic and isophthalic-based thermosets). Sisal fibers were subjected to washing in order to remove the organic coating on the fibers (which were originally prepared for cord manufacture) and to maleic anhydride (MAN) esterification. The effect of these treatments on the thermomechanical properties of the composites, as well as on the mechanical properties (flexural and compression) and water absorption was investigated. All the results are coincident in showing the improved interfacial adhesion obtained by washing and mainly by esterification of the fibers. Additionally, hybrid wood flour sisal composites were prepared and their mechanical properties compared to those of the one-filler composites. The hybrid composites showed improved modulus and maximum stress.