Segmented Block Copolymers Based on Polyamide-4,6 and Poly(Propylene Oxide)

Abstract

Segmented block copolymers were obtained through copolymerization of nylon-4,6 and polypropylene oxide) (PPOx). An amine-terminated PPOx (“soft”) segment of molar mass 430 was reacted with nylon-4,6 salt in an autoclave (30 minutes, 210 °C, 7 bar). In this reaction a prepolymer was prepared, which was postcondensed afterwards. In ethanol, a considerable amount of material could be extracted from the solid copolymers of low polyamide content,i e those with short polyamide (“hard”, crystallizable) segments. Torsional tests showed an extended rubber plateau of fairly constant modulus. Whereas PPOx has a Tg of -60°C, the Tg’s of the copolymers were higher as a result of dissolution of uncrystallized polyamide segments in the PPOx phase. The high melting point of nylon-4,6 was approached only by copolymer of high polyamide content.