KINETIC AND MICROSTRUCTURAL PARAMETERS OF THE FREE-RADICAL COPOLYMERIZATION OF 2-HYDROXYETHYL METHACRYLATE WITH METHACRYLIC MONOMERS BEARING BULKY POLAR SIDE-GROUPS

Biocompatible copolymers of N-(4-methacryloyloxyphenyl)-2-(4-methoxyphenyl)acetamide (OM) and N-[4-(4-methoxyphenylacetyloxy)phenyl]methacrylamide (MA) with 2-hydroxyethyl methacrylate (HEMA) were prepared by free-radical polymerization. The kinetic behaviour of these systems was studied gravimetrically, and the results obtained are discussed in the light of kinetic models. The reactivity ratios were determined by the application of linearization methods to the general copolymerization equation, as well as by non-linear least-squares analysis, the most correct values being r(OM) = 1.49, r(HEMA) = 0.61 and r(MA) = 0.29, r(HEMA) = 1.47. The microstructure of copolymer chains was determined statistically from the reactivity ratios, considering the terminal model for both copolymerization processes.