Room-temperature self-healing polysiloxane elastomer with reversible cross-linked network

Abstract

The linear self-healing matrix had certain defects in the aspects of physical and mechanical properties, heat resistance and solvent resistance, which limited its application in engineering. However, if the conventional cross-linked structure was integrated into material matrix, the self-healing properties of the material would be sacrificed seriously. To address the drawbacks of linear and cross-linked self-healing polymers, reversible cross-linked structural units were designed to balance the two aspects. The silicone elastomers were endowed with outstanding mechanical properties and self-healing ability at room temperature by introducing a tri-functional cross-linking agent “Trimer of hexaethylene-diisocyanate (Tri-HDI)” to PDMS linear structure, and distributing dynamic disulfide bonds around of the cross-linking points to build the reversible cross-linking structural units. The influence of cross-linker content on the mechanical properties, self-healing properties and heat resistance of the elastomer was systematically investigated in this paper. Then, the soft and hard segment structures at different temperatures of the self-healing materials was characterized by low-field NMR as an innovative structural characterization. This room temperature self-healing elastomer with reversible cross-linked structure had great potential for industrial applications.