三元乙丙橡胶共混改性聚丙烯

分别用茂金属催化聚合所得的三元乙丙橡胶(mEPDM)和传统Ziegler-Natta催化剂聚合所得的三元乙丙橡胶(EPDM)对PP进行共混改性。考察了增韧剂质量分数对共混物冲击强度、拉伸强度和热变形温度等力学性能的影响，以及共混物结构形态和结晶行为。结果表明，与PP／EPDM共混物相比，PP／mEPDM共混物的脆韧转变增韧剂临界质量分数小，扯断伸长率高。PP／mEPDM共混物的脆韧转变区间远小于PP／EPDM共混物。随增韧剂质量分数的增加，PP／mEPDM和PP／EPDM共混物的拉伸强度、弹性模量和维卡软化点均单调下降，但后者的下降幅度更大。电镜分析和结晶行为研究表明，PP与mEPDM的相容性优于PP与EPDM的。

Blending modification of PP by EPDM

The ethylene -propylene -diene monomers polymerized by metallocen e catalyst(mEPDM)and by conventional Ziegler -Natta c at-alyst(EPDM)were used to blend with PP to modify its toughening.The effect of mass fr action of elas-tomers on the mechanical properties such as impact strength,tensile strength,and Vic at softening point of the PP /elastomers blends was investigated.The re-sults showed that compared with PP /E PDM blends,PP /mEPDM blends had lower critical m ass fraction of toughener when the brittle -ductile transition oc-curred and the elongation at break of PP /mEPDM blends was longer than that of PP /EPD M blends.Itwas found that the brittle -ductile t ransition interval of PP /mEPDM blends was much narrower than that of PP /EPDM blends.With increasing t he mass fraction of toughener,the tensile s trength and elastic modulus of blends decreased,but the decreasing amplitude of PP /mEPDM blends was min or.The blends were analyzed by of SEM and DSC and the results showed better compatibility between PP and mEPDM.