New elastomeric polyurethane coating made with polycarbonate diol with intrinsic self - healing

 
Self-healing materials self-repair with time once they suffer cuts. Recently, polyurethanes showing self-healing have been developed, such as those made with separate liquid isocyanate+polyol, or diamine molecule containing disulfide aromatic moiety. However, all those polyurethanes need the external agents (heat, radiation) or the time for sufficient self-healing is long. In this study a different approach is proposed for synthesizing elastomeric polyurethanes which, after being cut, self-heal in less than 30 seconds at 25ºC. Furthermore, they show adhesion and have potential as smart coatings. Polycarbonate diol polyol and/or polycarbonate diol-based prepolymer were used to synthetize fully clear transparent polyurethanes. The extent of self-healing was evaluated by cutting completely polyurethane pieces by the middle, rejoining them and obtaining the stress-strain curves at different times. Irrespective of the nature and the molecular weight of the polycarbonate diol, satisfactory self-healing was obtained 30 seconds after rejoining (60% at least of the original mechanical properties).