High performance poly(urethane-imide) prepared by introducing imide blocks into the polyurethane backbone

Synthesis of Interpenetrating Polymer Networks Based on Triisocyanate-Terminated and Modified Poly(urethane-imide) with Superior Mechanical Properties

Interpenetrating polymer networks (IPNs) based on triisocyanate-terminated poly(urethane-imide)s (PUIs) were prepared by in situ interpenetrating reactions between modified polyurethane (PU) with different ratios of polyimide (PI). The effects of PU, which was made from hydroxyl-terminated polybutadiene modified with triisocyanate, and the amounts of PI on the mechanical properties, thermal properties, and crystalline character of the IPNs were discussed. Triisocyanate-terminated PUI showed that the highest tensile strength was 38 times that of the diisocyanate-terminated materials. Supramolecular cross-linking from an additional hydrogen-bonding network of modified PU and the degree of interpenetration with a regular imide structure of PI were introduced, which accounted for the remarkable improvement in mechanical properties of IPNs. Preferable thermal stability and glass transition temperature for the hard segment of IPNs were rewarded with increasing PI content. X-ray diffraction revealed vigorous segmental mixing between the soft and hard segments of modified PUI. Scanning electron micrographs showed the "fibrous assembly" morphology and short-range-ordered structure of modified PUI.

Synthesis, characterization, and properties of novel UV-resistant poly(urethane-imide)/POSS nanocomposite

In this study, a series of hybrid nanocomposites composed of poly(urethane-imide) (PUI), fluoroethylene vinyl ether copolymers, and octa-aminophenyl polyhedral oligomeric silsesquioxane (POSS) were successfully prepared. Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), contact angle analysis, thermogravimetric analysis (TGA), and dynamic mechanical analysis were used to characterize the hybrid nanocomposites, which were found to have excellent thermostability, mechanical strength, and ultraviolet (UV) resistance. The SEM results showed that POSS nanoparticles, at low content level, could disperse homogeneously in the PUI matrix. The TGA results confirmed that the thermostability of the hybrid nanocomposites was significantly improved by the addition of POSS. Moreover, the UV-resistant property of the nanocomposites was evaluated based on the change in mechanical property and weight loss caused by the UV radiation. POSS (5 wt%) achieved the highest efficiency in enhancing the UV resistance of the nanocomposites. After UV radiation, the tensile modulus of the nanocomposite without POSS decreased to 187 MPa, and the mass loss was 7.26%. In contrast, the tensile modulus of the nanocomposite containing 5 wt% POSS increased from 412 MPa to 444 MPa, and the mass loss was only 3.76%.