Writer:Wu Wei

Abstract：The morphologic characteristics and toughened effect of three EPDMs in dynamically vulcanized PP/EPDM blends were investigated by SEM and the ethylene contents in the said EPDMs were 53%,45% and 75% by weight respectively.The results showed that the EPDM with the ethylene content between 45%55% by weight gave lower structure regularity,higher melting viscosity and poor compatibility with PP,the dynamic vulcanization resulted in smaller dispersive EPDM granules, more uniform granule size and distribution,and the increase of shearing strength in blending was benefitial to the toughening effect of this EPDM;and the EPDM with the ethylene content up to 75% by weight gave partial crystallinity due to the formation of homopolymerized ethylene in EPDM,lower melting viscosity and better compatibility with PP,the dynamic vulcanization resulted in greater dispersive EPDM granules and a subnetwork structure,the network density and continuity were increased by promoting the chemical crosslinking reaction and thu s the toughened effect was increased,in contrast,the toughened effect was decreased by increasing the shearing strength in blending.