VISCOSITIES OF ETHYLENE-PROPYLENE DIENE TERPOLYMER BLENDS IN OIL

Viscosities were obtained on oil solutions of two ethylene-propylene-d iene terpolymers (EPDMs) and their blends. For the amorphous terpolyme r with 59 mol % ethylene, intrinsic viscosities were constant between -10 and 40-degrees-C. The viscosities decreased rapidly at low tempera ture for blends of this material with as little as 20 wt % of a slight ly crystalline EPDM with 79 mol % ethylene. Dynamic viscosity measurem ents on 1.0% solutions of blends likewise gave considerably smaller va lues at low temperature than measurements on an amorphous EPDM of simi lar molecular weight. The data are in agreement with the view that lon ger ethylene sequences that crystallize in the bulk polymer can organi ze in oil into ordered domains that interfere less with flow than the disordered amorphous polymer regions.