Constitutional and configurational influences on the viscoelastic data of methyl substituted hydrocarbon macromolecular systems

Abstract

From viscoelastic measurements on the melts of non-entangled atactic head-to-tail and of head-to-head — tail-to-tail polypropylenes over a broad region of temperatures and frequencies it is concluded that the head-to-tail macromolecules are the significantly less mobile ones. Equimolar blends of both components show up one-phase behaviour. A tendency towards beginning incompatibility may be concluded, however, from some characteristics of the blend: Additional transition in the glassy state, at 210. 3 K, increased fractional free volume and raised zero shear melt viscosity.