Preparation and properties of highly branched poly(urethane-imide)-epoxy cross-linked copolymer

Highly branched poly(urethane-imide)-epoxy (AHBPUI-EP) cross-linked copolymer was prepared by the reaction of epoxy resin (EP) with amino-terminated highly branched poly(urethane-imide) via A 2 + B 3 approach. The structure and properties of the AHBPUI-EP cross-linked copolymers were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, tensile tests, and X-ray diffraction, respectively. It has been found that the increasing of the Tg of the cross-linked copolymer was resulted from the high density of cross-linking. The thermal stability was enhanced after introducing both imide and epoxy. The initial degradation temperature was up to 332.68 °C. Moreover, the mechanical properties changed with changing the content of EP, imide and the ratio of [A 2 ]/[B 3 ].