PROPERTIES OF VINYLPYRROLIDONE-TERT-BUTYLPHENYL METHACRYLATE COPOLYMERS IN SOLUTION.

In the reported experiments, copolymers of vinylpyrrolidone-p-tert-butylphenyl methacrylate (VP-MBPh) of several compositions were prepared by polymerization in benzene at 50 degree C using alpha prime alpha prime -azobisisobutyronitrile as initiator. Number-average molecular weights of fractionated samples were determined by osmotic pressure in benzene or 2-propanol. From the relation between M//n and the intrinsic viscosity left bracket eta right bracket , it appears that these random copolymers behave as predicted by the theory for flexible polymers. Abnormal viscometric behavior shown by one of the copolymers in nitromethane at 29 degree C (the theta temperature) is discussed. The Stockmayer-Fixman semiempirical method was used for estimating unperturbed dimensions from viscosity data obtained in chloroform, a good common solvent. Values of the viscosity parameter K// theta values are higher than those calculated for the homopolymers.