Effects of coagulation processes on properties of epoxidized natural rubber

The epoxidized natural rubber (ENR) with epoxy group contents of 48.4% were coagulated with ethanol and steam and the structures, processing performances, antioxidative behaviors, cure characteristics, and dynamic mechanical properties were analyzed using infrared spectroscopy, rubber processing analyzer, thermogravimetric analyzer, rheometer, and dynamic thermomechanical analyzer, respectively. The results indicate that the ENR coagulated with ethanol (ENR-e) exhibits a compact structure and the contents of residual low-molecular-weight matters are higher than those of unconsolidated ENR coagulated with steam (ENR-s). Therefore, the processing performance and antioxidative behavior as well as the curing characteristics of ENR-e compound are poorer than those of ENR-s. Although the mechanical properties and wet skid resistance of ENR-s vulcanizate are poorer than those of ENR-e, the heat build-up or rolling resistance of ENR-s is better than that of ENR-e. (C) 2008 Wiley Periodicals, Inc.