Abstract:
Polymer blends between unsaturated polyester resin and styrene grafted natural rubber latex were prepared by mixing these two components, Methy ethyl ketone peroxide as an initiator and co-octoate as an accelerator. The mixtures were then cast at room temperature. The influences of the type of natural rubber latex, the amount of PS grafted on NR and the ratio between grafted copolymer and unsaturated polyester resin on mechanical properties and morphology of polymer blends were studied. It was found that as the amount of PS grafted on NR increased from 95/5, 90/10, 80/20 to 70/30, impact strength and flexural strength of polymer blends decreased. Furthermore, it was also observed that as the amount of PS grafted NR in polymer blend increased from 5, 10, 20, 30 to 40 g, both mechanical properties decreased. SEM studied revealed that the dispersion of polystyrene grafted natural rubber latex was better than that of ungrafted natural rubber latex. However, an increase in the amount of graft copolymer in polymer blends produced more voids in the products; consequently, reducing both impact strength and flexural strength of the polymer blends to be less than those of pure unsaturated polyester resin.