Effect of dynamic crosslinking on rheological properties of molten polypropylene ethylene-propylene elastomer blends

Dynamic mechanical properties of uncrosslinked and dynamically crosslinked polypropylene/ethylene-propylene elastomer blends in the melt were compared. It was found that the dependence of dynamic viscosity and storage modulus on frequency reflects the type of phase structure of uncrosslinked blends. Dynamically crosslinked blends with higher contents of elastomer shaw rheological properties which are typical of systems where the physical network of dispersed particles exists. Rheological properties of dynamically crosslinked blends at low frequencies and low shear rates were explained as a consequence of long-lived entanglements among touching crosslinked elastomer particles. (C) 1997 Elsevier Science Ltd.