Self-healing supramolecular waterborne polyurethane based on host-guest interactions and multiple hydrogen bonds

Polymers which contain 2-Amino-4-hydroxy-6-methylpyrimidine (UPy) usually show good self-healing capabilities under certain conditions. In this study, the UPy was grafted into the side chain of waterbome polyurethane (WBPU), which was synthesized from 4,4-diisocyanate dicyclohexylmethane (H12MDI) and polycarbonate diol (PCDL), for giving the function of self-healing to the polymer. Meanwhile, the methylated beta-cyclodextrin (M-beta-CD), which was able to enhance the mechanical properties of WBPU and realize the synergistic effect between M-beta-CD and UPy to raise the performance of self-healing, was introduced onto the main chain of WBPU. The T-g (glass transition temperature) of the polymer can be observed from dynamic mechanical property analysis (DMA) below room temperature, which facilitated the movement of the chain in self-healing process. From the tensile test, it showed that the cut polymer spline displayed a self-healing efficiency of 92.29% at 100 degrees C within 36 h. Furthermore, the disappearance of surface scratch of polymer film was observed by heating under a polarized microscope (POM) with a heating table. The results manifested that SWBPU exhibited great application as an intelligent response-type material.