Toughening Studies of an Unsaturated Polyester Resin Using Maleated Elastomers

Unsaturated polyester resins are extensively used in the fibre-reinforced plastic industry. The fracture toughness and impact resistance of rigid unsaturated polyester can be improved by the incorporation of elastomers by physical and chemical methods. In the physical method, two strategies are adopted. In the first, various masticated elastomers are dissolved in styrene and blended with unsaturated polyester resin. In this study, the mechanical properties of cured blends are compared with the unmodified resin and the performance of nitrile rubber is found to be far superior to all other rubbers considered. In the second approach, elastomers are modified by grafting with maleic anhydride. These maleated elastomers are then dissolved in styrene and blended with polyester resin. Maleic anhydride modified elastomers are found to improve the mechanical properties such as toughness, impact resistance and tensile strength of the cured resin to a greater extent compared to unmodified elastomers.