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Diels–Alder-based crosslinked self-healing polyurethane/urea from polymeric methylene diphenyl diisocyanate



Crosslinked self-healing polyurethane/urea based on a Diels–Alder reaction (C-PMPU–DA) was synthesized from a multiple-furan monomer and a commercial bismaleimide. The multiple-furan monomer (PMPU–furan) was obtained from a functionalized prepolymer (polymeric MDI: PBA-2000 = 2:1) by furfuryl amine. The structures of both the PMPU–furan and C-PMPU–DA were characterized by attenuated total reflectance (ATR)–Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and 1H-NMR. The Diels–Alder bonds enabled C-PMPU–DA thermal reversibility, which was investigated by ATR–FTIR spectroscopy, 1H-NMR, gel–solution–gel experiments, and viscosity tests. Meanwhile, the self-healing properties of C-PMPU–DA were also investigated by the recovery of the mechanical properties. The results showed that C-PMPU–DA exhibited good thermal reversibility and self-healing properties. C-PMPU–DA exhibited thermosetting properties at room temperature, although it exhibited thermoplastic properties at higher temperatures and may find applications in self-healing materials, recyclable materials, or removable materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40234.