HIGH PERFORMANCE STYRENIC THERMOPLASTIC VULCANIZATES WITH GOOD ELASTIC RECOVERY AND HEAT STABILITY AT ELEVATED TEMPERATURE

摘要

In this paper,a comparative study of styrenic thermoplastic vulcanizates (STPVs) and conventional polypropylene / EPDM thermoplastic vulcanizates (TPVs) is presented.STPVs consist of polypropylene as the continuous phase and crosslinked modified hydrogenated styrenic block copolymer as the dispersed phase.The material characteristics under investigation are mechanical properties,rheological properties,dynamic mechanical properties,heat aging properties and morphology.When compared to conventional TPVs,the elastic recovery and retention of tensile strength and elongation at break of STPVs have approximately 20 % and 10 % improvement after 1440 hours of aging at 125°C,respectively.Furthermore,STPVs after 500 hours of oil immersion at 125°C shows a 20 % improvement in hot oil resistance over conventional TPVs.These observed property improvements for styrenic thermoplastic vulcanizates relative to conventional TPVs are explained in part by the dual network morphology of the resulting compound.These performance characteristics make STPVs suitable for high temperature and chemical environment applications.This new TPV technology is expected to bridge the gap between polypropylene/EPDM TPVs and more costly engineering TPVs.