Design of Self-Healing Rubber by Introducing Ionic Interaction To Construct a Network Composed of Ionic and Covalent Cross-Linking

Abstract

Introducing reversible ionic interaction is one of the most effective methods to achieve self-healing behavior in rubbers. However, the strength of the rubbers only containing an ionic cross-linking network is quite limited, and their long-term stability is questionable. In this work, polar epoxidized natural rubbers (ENR) filled with zinc dimethacrylate (ZDMA) were vulcanized with a peroxide cure system to obtain a self-healing material. We controlled vulcanization parameters to inhibit the formation of covalent cross-linking network and constructed a network composed of covalent and ionic cross-linking. In the presence of a slightly covalent cross-linking network, the mobility of rubber chains is almost unlimited, and the composite exhibits high strength and stability. The rearrangement of rubber chains is still prone to occur, which promotes the self-repairing behavior of the rubber and allows the fully cut sample to undergo proper self-healing at ambient temperature.