The effect of PP molecular weight on the complex viscosity of PP/EPDM blends

The effect of the molecular weight of isotactic polypropylene (PP) on the complex viscosity of unvulcanized and dynamically vulcanized blends of PP with ethylene-propylene-diene monomer (EPDM) was investigated. It was shown that individual PPs and PP/EPDM blends demonstrate a shear thinning behavior. The flow index varied with frequency and elastomer content for all blends. The dependences of complex viscosity versus PP molecular weight were observed for unvulcanized blends based on 25 wt% EPDM. The viscosity of composition with higher elastomer content was not practically affected by the variation of PP molecular weight. The complex viscosity of dynamically vulcanized blends depended on PP molecular weight, blend composition, and nature of crosslinking agents.

Automated summary

The study showed that the molecular weight of isotactic polypropylene (PP) affects the complex viscosity of unvulcanized and dynamically vulcanized blends of PP with ethylene-propylene-diene monomer (EPDM), with varying effects depending on the blend composition and crosslinking agents used.