Synthesis and flame retardancy of novel thermally stable poly(imideurethane)s containing imide and alkynyl groups in main chain

A kind of glycol containing imide and alkynyl function was synthesized from pyromellitic dianhydride(PMAD), butynediol(2-butyne-1, 4-diol) and D, L-phenylalanine(DLP). Linear imide and alkynyl modified thermoplastic poly(imide-urethane)s were prepared by the obtained glycol, 4, 4'-diphenylmethane diisocyanate(MDI) and poly(tetrahydrofuran)(PTMG) via prepolymerization. The poly(imide-urethane)s structures were characterized with Fourier transform infrared spectroscopy(FTIR), universal testing machine tension, thermalgravimetric analysis(TGA), wide-angle X-ray diffraction(XRD). The results showed that the novel thermoplastic poly(imide-urethane)s elastomer with amorphous structure were successfully synthesized. The tensile strength increases with the hard segment contents. Comparing with the conventional thermoplastic polyurethanes extended by 1, 4-butanediol, the poly(imide-urethane)s show slower thermal degradation rate during the degradation process. The polymers with different hard segments contents all reach a UL-94 V-2 rating, and the limiting oxygen index(LOI) value increases with different hard segments contents.