Study of Diels-Alder Reactions Between Furan and Maleimide Model Compounds and the Preparation of a Healable Thermo-Reversible Polyurethane

A study of the reactions between various furan and maleimide model compounds and the effects of reaction conditions was performed, allowing for a proper design and preparation of a thermo-reversible polyurethane (PU) material crosslinked via Diels-Alder (DA) bonds. Thus, a linear polyurethane containing furan groups along the main chain was synthesized and crosslinked with a bismaleimide by means of DA reaction. The obtained thermoset exhibited thermo-reversibility as evidenced by DSC and FTIR microscopy, providing the material recyclability and scratch healability. Optical microscopy, SEM and tensile analysis of a scratched PU film revealed that efficient scratch healing was enabled by heating at 110 degrees C for 30 min and subsequently keeping at room temperature for 24 h, resulting in an approximately 80% recovery of the pristine mechanical strength. This material is a promising candidate for the development of self-healing coatings. (C) 2018 Wiley Periodicals, Inc.