Viscoelastic behavior of polymerizing systems

Experimental data of the dynamic viscoelastic properties, storage modulus ( G'), loss modulus (G"), and phase shift (delta) as well as of the viscosity , eta, are reported for the polymerization of a free radical polymerization system (methyl methacrylate) which exhibits the Trommsdorff effect. A rheo meter-reactor assembly developed in our laboratory is used for this purpose . It is observed that in the early stages of reaction, data lie in the term inal zone. As the polymerization progresses, the Trommsdorff effect leads t o a sharp increase in both the polymer concentration and the weight average molecular weight, and the viscoelastic properties then lie in the entangle ment zone. A modulus crossover point:(when G' = G") is identified that coul d be used as an identification of the point where the Trommsdorff effect st arts assuming significance.