Synthesis and properties of poly(amide‐imide‐urethane) thermoplastic elastomers

A new class of poly(amide-imide-urethane) thermoplastic elastomers based on two-step synthesis of 4,4′-methylene bis(4-phenylisocyanate) with different polyols (PPG and PTMG) and trimellitic anhydride was synthesized. Both resulting polymers showed semicrystalline structures and were readily soluble in polar solvents such as N-methyl-2-pyrrolidone and dimethyl formamide. The soluble poly(amide-imide-urethane)s afforded transparent, flexible, and tough films. Both new copolymers were then characterized by FTIR spectroscopy, universal tensile tester, simultaneous DTA/TGA (SDT), differential scanning calorimetry (DSC), and wide-angle X-ray diffraction studies, to determine their morphological structures, thermal stability, and mechanical properties. Compared to typical polyurethanes, these polymers exhibited better thermal stabilities due to the presence of imide groups. DSC and X-ray diffraction studies showed semicrystalline patterns for these polymers. Stress–strain properties revealed that these polymers have good extensibility like typical polyurethanes.