Abstract
It has been found that the combination of liquid diene rubbers and a large amount of sulfur content leads to very high hardness to EPDM vulcanizates. The newly developed EPDM compounds have also good processability.
It order to investigate the hardening mechanism, the EPDM vulcanizates were analyzed by using electron microscope and electron prove micro-analyzer. In the vulcanizates, diene rubbers were in a dispersion phase and EPDM was in a continuous phase. The amount of sulfur contented in diene rubber phase was found to be about ten times as much as EPDM phase. From the result, it is concluded that diene rubbers from hard particles cross-linked by large quantity of sulfur and these hard particles harden the EPDM vulcanizates.
