Preparation of FKM/EFEP thermoplastic vulcanizate with excellent heat and oil resistance, gas barrier property and recyclability

Because of the fuel diversification, the harsher use environment and the requirements of environmental protection, the automotive fuel pipeline system requires not only good mechanical properties and high elasticity but also high temperature and oil resistance, high gas barrier property, easy processibility, and recyclability. Nevertheless, the traditional materials cannot simultaneously meet the requirements of these properties. In this study, fluororubber (FKM)/fluoro-thermoplastic (EFEP) TPV (FTPV) with fine dispersion of FKM rubber phase in EFEP matrix was successfully produced through the design and optimization of crosslinking systems of FKM and the processing technology. The as prepared FTPV not only shows good mechanical properties, elasticity, rheological property and recyclability, but also excellent oil resistance and gas barrier properties, outperforms the other TPVs. The mechanism on morphological development of the FKM/EFEP TPV are revealed. Interestingly, a large number of single rubber sub-micron particles (RPs) are formed in the blend during the dynamic vulcanization, which is mainly attributed to an improvement in compatibility and an increase in crosslinking degree of FKM. The combined effect of shearing stress and the improvement of compatibility results in a decrease in the size of rubber sub-micron particles agglomerates and an increase in the content of single rubber sub-micron particles.