COPOLYMERIZATION AND TERPOLYMERIZATION OF METHACRYLIC ESTER MONOMERS CONTAINING HYDROXYL-GROUPS IN THEIR STRUCTURE

Copolymerization and terpolymerization of three methacrylic monomers, 3-hydroxyneopentyl methacrylate (NPGMA), 2-hydroxyethyl methacrylate ( HEMA) and methyl methacrylate (MMA), have been studied. Attention has been devoted to quantitative analysis of the experimental results for determining the reactivity ratios, which were obtained by the Kelen-Tu dos and Tidwell-Mortimer methods in the copolymerization reactions. A method developed in our laboratores to determine the reactivity ratios (r(ij)) in multicomponent systems was used in the terpolymerization o f these monomers. The values of r(ij) obtained were different from tho se previously calculated by binary copolymerizations. Azeotropic react ions occur in the case of MMA-NPGMA copolymerization and in the terpol ymerization extending over practically all the interval of composition . Microstructural effects on the glass transition temperature (T-g) of HEMA-NPGMA copolymers and terpolymers were observed, indicating the i nfluence of sequence distribution of the monomer units on that propert y. In the other copolymers the values of T-g were not influenced by th e sequence distribution and are given directly as a function of the we ight fraction of the comonomer. Copyright (C) 1996 Elsevier Science Lt d.