Blending polar rubber with polyurethane to construct self-healing rubber with multiple hydrogen bond networks

Preparation of traditional rubbers with excellent self-healing ability is a difficult issue in the field of polymer materials. In the current work, we proposed a new way to fabricate self-healing traditional rubber by blending the polar rubber (epoxidized natural rubber, ENR) with the other polar polymer (polyurethane, PU) containing CC bonds and 2-ureido-4[1H]-pyrimidinone (UPy) groups (PU-UPy). It was demonstrated that the ENR/PU-UPy blend exhibits high self-healing efficiency. During curing, slightly covalent network forms in the blend, which is beneficial for the improvement in the compatibility between the two polymers. Multiple hydrogen bond networks including intermolecular hydrogen bonds between the ENR chains and the PU-UPy chains and strong hydrogen bonds between the UPy groups determine the excellent self-healing ability of the blend. The current blending method provides new ideas for the design of new self-healing traditional elastomers.