EPDM分布形态对动态硫化PP/EPDM共混物增韧效果的影响及其机理的研究

采用扫描电子显微镜（ＳＥＭ）技术研究了乙烯质量分数分别为０５３，０４５和０７５的３种ＥＰＤＭ与ＰＰ组成的动态硫化共混物的形态结构特征及其增韧效果。结果表明，当ＥＰＤＭ中乙烯质量分数在０４５～０５５之间时，ＥＰＤＭ的结构规整性差、熔融粘度高、与ＰＰ相容性小，动态硫化的实质是使ＥＰＤＭ分散颗粒由大变小、粒度均化、分布均匀，增大共混剪切强度有利于提高这种ＥＰＤＭ的增韧效果。当ＥＰＤＭ中乙烯质量分数达到０７５时，ＥＰＤＭ中因出现均聚ＰＥ序列结构而呈现部分结晶性，熔融粘度低，与ＰＰ相容性增大，动态硫化后ＥＰＤＭ分散颗粒由小变大，并同时形成“亚网结构”，强化化学交联反应可提高网络密度及网络连续性，从而提高增韧效果，而提高共混剪切强度，反而会使增韧效果下降

Influence of EPDM Distributive Morphology on Toughened Effect of Dynamically Vulcanized PP/EPDM Blends and Its Mechanism

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 45U% 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.