VISCOELASTIC FEATURES OF MOLTEN BLENDS OF POLY(VINYL CHLORIDE) POLY(ETHYLENE-VINYL ACETATE)

Dynamic viscoelastic measurements and extrusion rheometry results of i mmiscible and partially miscible PVC/EVA blends from 50 to 90 wt% in P VC are presented and compared with those of plasticized PVCs, From los s modulus data the plateau modulus, G(N)(o), associated with entanglem ents, is calculated. The variation of G(N)(o) will composition is anal yzed using the theory of Tsenoglou. A simple model, which accounts for the effect of a structural parameter and the effect of free volume, i s used to adjust viscosity data, taken at several frequencies and shea r rates. For both types of blends, best its are obtained using a model that establishes that the free volume of each polymer is not measurab ly altered by the other.