Shrinkage reduction of thermoset matrix particle reinforced composites during curing using microwaves irradiation

Abstract

[Abstract]: Composites made from vinyl ester resins suffer considerable shrinkage during curing and after solidification. This shrinkage is particularly serious if the fibre composite components are large and can be up to twelve percent (Schwartz, 1992; Clarke, 1996; Matthews and Rawlings, 1994). Currently, the shrinkage problem is solved by breaking a large composite component into smaller composite parts because smaller parts tend to have less shrinkage. These smaller parts are then joined together to form the overall structure. However, the manufacturing lead-time and costs of a composite component are significantly increased. This project attempts to reduce the shrinkage of the components cast from uncured 33% by weight or 44% by volume of fly ash particulate-reinforced vinyl esters [VE/FLYASH (33%)]. This is accomplished by shortening the curing time of the resins using penetrating microwave energy. The formation of pinholes in the samples resulted in the expansion of the volume of the materials in the initial stage of the curing process. Microwave irradiation did reduce curing shrinkage in the composite.