Self-healing and degradable functionalization of EVA hot-melt adhesives based on disulfide bonds and polymer free radical copolymerization

Abstract

This study aims to provide a new approach for the industrialization of self-healing adhesive or membrane materials. EVA hot melt adhesive has a market share of over 50 %, and it needs to be cured during use. It is a thermosetting resin that is difficult to recycle and reuse. In response to the defects mentioned above, we developed a self-healing and degradable EVA-based hot-melt adhesives (EDS) based on disulfide bonds and polymer free radical copolymerization. Specifically, we used divinyl disulfide as a crosslinking agent. Under the action of a peroxide initiator, disulfide and EVA formed a cross-linked network through free radical copolymerization. In the study, we characterized the Functionality and comprehensive performance of EDS using various testing methods such as FT-IR, DSC, and SEM. The research results indicate that EDS achieves self-healing and degradation by utilizing the rearrangement reaction of disulfide bonds under ultraviolet light and its reducibility under strong alkaline conditions. While maintaining the same electrical insulation performance, the barrier performance, thermal conductivity, aging resistance, and mechanical properties of EDS have all been improved. Meanwhile, we discussed the self-healing mechanism, curing kinetics, degradation mechanism, and aging mechanism of EDS.