Abstract
Ethylene-propylene-diene rubber (EPDM) compounded with dicumyl peroxide (DCP) and modified polyphenylene ether (mPPE) are bonded directly without an adhesive on the conditions of rubber crosslinking. In this study, the mechanism of the direct adhesion between EPDM compounded with DCP and mPPE was investigated. In addition, polyamide 66 (PA66) and polyoxymethylene (POM) instead of mPPE were studied.
The EPDM/mPPE composite resulted in a breakage of the EPDM layer in adhesive strength tests. In order to analyze the interface, mPPE was dissolved in chloroform. It has been found that a crosslinking mPPE layer was formed in the interface by using attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy, and the crosslinking layer was built by DCP diffusing from EPDM into mPPE. Carbon radicals in the mixture of mPPE and DCP were detected by electron spin resonance (ESR) at the crosslinking temperature (180°C). On the other hand, the interfacial failure was occurred in EPDM/PA66 composite, because DCP diffusing into PA66 didn't efficiently affect radical generation in PA66: In the EPDM/POM composite, the interfacial failure occurred, because POM was not crosslinked by DCP diffusing into POM.
