Blends of Unsaturated Polyester Resin with Functional Elastomers

Abstract

Unsaturated polyester resins are widely used in the fiber-reinforced plastic industry. The fracture toughness and impact resistance of rigid unsaturated polyester can be improved by blending with elastomers bearing reactive functional groups. In this study, blends of unsaturated polyesters are prepared with functional rubbers such as hydroxy terminated polybutadiene, epoxidized natural rubber, hydroxy terminated natural rubber, and maleated nitrile rubber. The mechanical properties of the cured blends are compared with the control resin. The elastomers bearing reactive functional groups show better compatibility with the resin and improve the toughness and impact resistance of the cured resin substantially, compared to unmodified elastomers. The performance of maleic anhydride-grafted-nitrile rubber is found to be far superior to all other rubbers considered in this investigation. An improvement in toughness, impact resistance, and tensile strength has been achieved without seriously affecting any other property.