Influence of liquid isoprene on rheological behavior and mechanical properties of polyisoprene rubber

Prevention of plasticizer leaching from polymers has been a difficult task. Conventional oily plasticizers (COPs) often migrate from rubber matrix, leading to a poor stability of rubber products and serious environmental problem during long-term use. In the present study, liquid isoprene (LIP) with appropriate molecular weight and no migration was prepared by anionic polymerization. The effects of LIP on the comprehensive properties of carbon black filled polyisoprene rubber (CB/IR) composites were compared with those of one COP, naphthenic oil (NPO). The results showed that LIP reduced the Mooney viscosity and apparent viscosity, and improved the processability of CB/IR composites. LIP improved the mixing efficiency and the dispersion of the CB particles because its compatibility with CB/IR composites was higher than the compatibility of NPO and CB/IR composites. Furthermore, LIP did not migrate from the CB/IR composites because of its participation in the vulcanization reaction. Compared with CB/IR/NPO composites, CB/IR/LIP composites possessed higher mechanical properties, better aging resistance and long-term dimensional stability. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41485.