GLASS TRANSITIONS IN DIMETHYL AND DI-N-BUTYL POLY(ITACONATE ESTER)S AND THEIR COPOLYMERS WITH METHYL-METHACRYLATE

Dimethyl and di-n-butyl esters of itaconic acid were polymerized and t heir glass transition temperatures along with those of copolymers obta ined with the mentioned ester of itaconic acid with methyl methacrylat e have been studied by differential scanning calorimetry. Homopolymer glass transitions decreased as the chain length of ester alkyl groups increased. The glass transition temperatures of copolymer have been an alysed as a function of the sequence distribution and their values com pared to the theoretical ones derived using Johnson's equation. The va lues for the supposed transition temperature of the alternating copoly mers, T-g12, are lower than the averages values expected from the addi tive contribution of the T-g of the corresponding homopolymers and dec reases as the itaconic diester chain lengthens. Comparison of these po lymers with the corresponding poly(n-alkyl acrylate)s and their copoly mers with methyl methacrylate highlighted the similarities in properti es. (C) 1997 Elsevier Science Ltd.