Preparation of Thermoplastic Elastomer from Epoxidised Natural Rubber and Polystyrene

The aim of this research was to prepare and investigate the behaviour of thermoplastic elastomers (TPE) from epoxidised natural rubbers (ENR) blended with polystyrene. ENRs with different amounts of epoxide groups were prepared via in situ epoxidation method and denoted accordingly as ENR25, ENR35 and ENR50. Polystyrene (PS) was prepared by emulsion polymerisation. The obtained ENRs were blended with commercial and prepared PS at room temperature in the latex state at the amounts of dry PS of 0, 20, 40, 60, 80 and 100 phr (parts per hundred rubber). The mechanical and thermal properties of the blend sheets were investigated. It was found that the tensile strength and elongation at break increased as the amount of PS increased, then decreased later at higher amounts of PS. However, these values decreased as the amount of epoxide groups increased. The hardness of the specimens increased with the increase of epoxide groups and PS content. For the determination of blend compatibility, a shift in glass transition temperature to a lower temperature was revealed by DSC analysis. According to the results, the ENR/PS blends could be described as partially miscible blends.