Hybrid Self-Repairing Polymer Composites Based on a Mixture of Intrinsic and Extrinsic Self-Healing

The development of high-strength and multiple self-healing polymer materials remains a major challenge. In this study, a hybrid self-healable polymer using the combination of intrinsic and extrinsic self-healing is demonstrated. The epoxy resin microcapsules with dynamic disulfide bonded shells are successfully prepared through an interfacial polymerization method, which are then added into the intrinsically self-healable epoxy resin substrate also containing disulfide bonds. The unique combination structure enables the polymer composites to exhibit high mechanical strength and excellent multiple self-healing efficiency. On the one hand, the Young's modulus and tensile strength of the material are enhanced due to the reinforcement effect of the fillers. On the other hand, the extrinsic self-healing strategy of the microcapsules, which released repair agents, can support the intrinsic repairing substrate to improve the self-healing ability of the material. More interestingly, the design of the disulfide bond structure of the microcapsule shell contributes to the high self-healing capability of the material during multiple self-healing processes.