Synthesis and properties of high-performance poly(imide-urethane) copolymers

Traditional elongation materials, such as polyurethane (PU) and rubber, display high mechanical extensibility under ambient conditions and are commonly used in various applications. However, their soft molecular structure results in low heat resistance and mechanical strength. In this study, we have used molecular structure design to synthesize a poly (imide-urethane) (PI-PU) copolymer to make the film with a high modulus and mechanical strength. We have controlled the elongation recovery, Hooke’s strength, and Hooke’s modulus of the PI-PU film by adjusting the molar ratio of dianhydride (PI monomer) to diol (PU monomer). We have used melamine as the reactive additives to improve the mechanical strength of the PI-PU film significantly. The PI-PU film is superior to commercial thermoplastic PU in terms of Hooke’s tensile modulus and elastocaloric effect, when the molar ratio of dianhydride to diol is 3.75:1.