Casting poly(urethane-imide) elastomers with improved thermoviscoelasticity

Polyurethane (PU) is a versatile material that can be customized to meet specific commercial requirements in different industries because of its favorable mechanical properties. However, it is not resistant to high temperatures, and it requires structural modifications before it can be used in high-temperature structural materials. In this study, isocyanates and anhydrides are copolymerized at high temperatures to obtain a solvent-free oligomer, thus eliminating the risks associated with highly polar aprotic solvents. A casting technique is used to synthesize a solid poly(urethane-imide) (PUI) elastomer. According to the results, casting PUI (CPUI) exhibits optimal physical properties at a hard segment content of 30.5%. Incorporating an ether, symmetric, or imide structure into CPUI may reduce its hysteresis and improve its thermal creep performance. Compared with PU, CPUI exhibits considerably higher creep aging resistance. In dynamic load application tests, CPUI wheels take a substantially longer time to reach failure compared with PU wheels. Overall, CPUI is an environmentally friendly material with high elasticity, low creep, and high heat aging resistance and is suitable for static and dynamic manufacturing applications.