Thermal analysis of solution copolymers of styrene with <i>N</i>‐phenylmaleimide

Abstract

Abstract Free‐radical–initiated copolymerization of N ‐phenylmaleimide (NPMI) with styrene (St) at 110°C in a toluene solution initiated by AIBN was carried out by a semibatch method. The compositions of the copolymers were determined by using an elemental analyzer. The glass‐transition temperatures of the copolymers were measured by differential scanning calorimetry. All the semibatch copolymers show a single glass‐transition temperature that increases markedly with increasing NPMI content in the copolymers. The thermal stabilities of the copolymers were studied by using a programmed thermogravimetric analysis technique. Copolymers show a considerable increase in thermal stability and different degradation reaction mechanisms with increasing content of NPMI. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 417–422, 2002