Polyether–maleimide‐based crosslinked self‐healing polyurethane with Diels–Alder bonds

Abstract

The Diels-Alder (DA) reaction is particularly desirable for the preparation of heat-stimuli self-healing polymeric materials because of its thermal reversibility, high yield, and minimal side reactions. Some attempts were conducted to synthesize polyethermaleimide-based crosslinked self-healing polyurethane with DA bonds (C-PEMIPU-DA) through the reactions of the prepolymer (polymeric MDI/PBA-1000) functionalized by furfuryl amine and polyether-maleimide without benzene in this study. The structures of intermediates and C-PEMIPU-DA were first confirmed by 1 H-NMR, Fourier transform infrared spectroscopy, and differential scanning calorimetry. Next, the thermal reversibility and the self-healing performance of C-PEMIPU-DA were studied by 1 H-NMR, polarizing optical microscopy, tensile testing, and a sol-gel process. The results show that C-PEMIPU-DA exhibited interesting properties of thermal reversibility and self-healing. The polymers could be applied to self-healing materials or recyclable materials in the fields of the repair of composite structures and aging parts because of their thermosetting properties at room temperature and thermoplasticity at higher temperatures.

Polyurethane adhesives containing Diels–Alder‐based thermoreversible bonds

“…The low concentration explains why the signature of the furfuryl groups in the Attenuated Total Reflection‐Infrared (ATR‐IR) spectrum of the prepolymer is much less pronounced compared to the contributions of MDI and CAPA. The strong absorption at 752 cm – , however, being characteristic of furfuryl alcohol can be identified clearly as a shouldering peak which confirms that furfuryl groups are present and have been grafted in the n = 2 modified prepolymer. Unreacted FA would have evaporated during the high temperature treatment in the vacuum oven.…”

“…Crosslinked polymers containing furfuryl and maleimide groups have been reported as well as linear alternatives but the synthetic routes are susceptible toward irreversible side‐reactions (particularly the Michael‐addition which occurs when maleimides are reacted in the presence of free nucleophiles at elevated temperature) or they involve the use maleimides that are not readily commercially available or the perspective is different from ours focusing on other applications including shape memory materials . An elegant approach is presented by Defize et al .…”

Molecular self-healing mechanisms between C60-fullerene and anthracene unveiled by Raman and two-dimensional correlation spectroscopy

“…2,4,6 In this context, the incorporation of functional groups into a copolymer to tune the material and self-healing properties according to the requirements is especially noteworthy. The most prominent fullerene representative is the icosahedral (C 60 -I h ) [5,6]fullerene. 3 Other good dienophile candidates for reversible [4+2] cycloadditions are fullerenes.…”

Polyurethanes as self-healing materials

“…This allows to heal FG-TPUR by three different methods: via IR light, electromagnetic wave or electricity 20 . Concurrently, reversible polymers based on Diels-Alder reactions are still examined and provide new self-healing materials like polyether-maleimide-based PUR 21 . …”