动态硫化三元乙丙橡胶/聚丙烯橡胶:流变、结晶和动态力学性能

Properties of PP/EPDM via Dynamic Vulcanization Method:Rheological Behavior, Crystallization and Dynamic Mechanical Properties

运用动态硫化法制备EPDM/PP橡胶,研究了其流变行为、结晶及动态力学性能。利用扫描电镜观察了硫化EPDM/PP橡胶熔融共混后EPDM颗粒在PP基体中的分散情况。动态力学性能(DMA)和拉伸性能测试的结果显示橡塑比为40/60时,EPDM/PP橡胶的综合性能最为优异。研究了硫化EPDM/PP橡胶在黏性弹性区域的振荡剪切行为。DMA结果显示橡塑比提高导致储能模量与tanδ下降。流变行为表明,复合黏度随交联密度的增加而增加,弹性变形优于黏性流动。硫化过程使EPDM颗粒细化导致PP分子链结晶受阻。

An approach to produce ethylene propylene diene monomer(EPDM)/polypropylene(PP) rubber has developed by dynamic vulcanization and the effect on the rheological behavior, crystallization, and dynamic mechanical properties of the PP/EPDM rubber was studied. A drastic transformation of oval or rounded EPDM particles into the PP matrix via melt compounding of EPDM/PP(rubber-plastic ratio of 40/60) was revealed by scanning electron microscopy(SEM) images. Dynamic mechanical analysis(DMA) and the tensile test show substantial improvements in the measured properties of the PP/EPDM rubber when the rubber-plastic ratio is 40/60. The oscillatory shear behavior of the PP/EPDM rubber in the linear viscoelastic region was studied. The DMA results display a decrease trend in storage modulus and tanδ which is caused by higher rubber ratio. The rheological behaviors show that the complex viscosity also increases with the increase of crosslinking density, and the elastic deformation becomes superior to viscous flowing in the EPDM/PP rubber. The crystallization of PP molecular chains is hindered by the refinement of EPDM particles during vulcanization.