Effect of low dose gamma irradiation on the tensile and thermal properties of natural rubber-based blend

Natural rubber (NR) is a renewable natural resource that has been utilized in many applications. Due to its low tensile strength, NR is commonly blended with another polymer to improve the properties of NR. However, most of the blended NR has miscibility issue, leading to poor mechanical properties. Gamma irradiation (GR) is a safe and green alternative than conventional chemical method for inducing crosslinking in blended NR. This study was aimed at investigating the mechanical and thermal properties of NR/liquid natural rubber/polystyreneb/ock-polyisoprene block copolymer (NR/LNR/PS-b-PI) blend using GR method. The polymer blend is prepared according to the ratio of NR:LNR:PS-b-PI of 6:1:3 using an internal mixer. The NR/LNR/PS-b-PI blends are irradiated with gamma ray at doses of 0, 5, 6, 7, 8 and 9 kGy. Tensile and thermal tests are conducted to evaluate the properties of unirradiated and irradiated polymer blend. The tensile strength and modulus of the irradiated blend are increased with increasing irradiation dose before decrease at 9 kGy. Lower melting point of blend indicates that PS-b-PI are compatible in NR/LNR blend. The improvement in tensile properties of irradiated NR/LNR/PS-b-PI blend is related to the radiation-induced crosslinking.