Thioacetate- and mercapto-functionalized hydrogenated natural rubber

Due to the differences in unsaturation levels of constituent rubbers, thioacetate and mercapto functional groups were introduced into hydrogenated natural rubber (HNR) to increase the compatibility of natural rubber (NR)/HNR blends. The effect of thioacetic acid and initiator concentrations including reaction time on the thioacetate content in HNR was investigated. Methanolysis of thioacetate-modified HNR (HNRTA) yielded mercapto-modified HNR (HNRSH). The addition of HNRTA or HNRSH into NR/HNR blends (50/50 wt ratio) increased the tensile strength. The improved mechanical properties of the compatibilized blends were confirmed by scanning electron microscopy, indicating a co-continuous morphology. Furthermore, the susceptibility of the vulcanizates to changes in temperature and ozone were also reported.