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 H-1-NMR. The Diels-Alder bonds enabled C-PMPU-DA thermal reversibility, which was investigated by ATR-FTIR spectroscopy, H-1-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. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40234.