Improved mechanical, thermal, and flame‐resistant properties of polyurethane–imide foams via expandable graphite modification

Abstract

ABSTRACTAlthough polyurethane–imide (PUI) foams combine the advantages of both polyurethane foam and polyimide foam, the performance of PUI might still not reach certain high‐level requirements. Thus, expandable graphite (EG), as a kind of effective reinforcing filler, was introduced into the PUI matrix to improve the physical properties of the foam. Furthermore, to enhance the interfacial compatibility, EG was surface‐modified with a silane coupling agent. The experimental results show that the addition of EG was beneficial for enhancing the comprehensive performance of the PUI foams, especially their thermal stability and flame resistance. In particular, the surface‐modified, EG‐filled PUI foam exhibited outstanding enhancements compared to that with only pristine EG incorporation; not only the compressive strength but also the thermal degradation properties were greatly enhanced by the increased interfacial compatibility between PUI and EG. In addition, the flame‐resistant properties were improved by the surface modification of EG. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46990.