Enhanced Self-Healing Performance of Natural Rubber via Zinc Disorbate Ionic Interactions

Abstract

One of the most critical environmental issues is improper disposal and processing of rubber waste. The development of self-healing properties in natural rubber (NR) aims to extend the lifespan of rubber products by repairing mechanical damage without compromising structural reliability or requiring operator intervention. In  this study, the self-healing capabilities of NR were investigated with different loadings of zinc disorbate (ZDS) as a self-healing agent. ZDS was incorporated into the NR compound using a peroxide vulcanization system with varying ZDS content. The tensile properties of the NR-grafted ZDS vulcanizate were measured before and after the healing process to determine self-healing efficiency. Fourier transform infrared spectroscopy (FTIR) and crosslink-density studies provided evidence of reversible ZDS ionic networks. Compared to unfilled NR, the results show that the addition of ZDS successfully enables the vulcanizates to self-repair and recover when damaged. The FTIR result showed that ZDS was successfully grafted onto NR molecular chains. Scanning electron microscopic (SEM) images demonstrated that the ZDS-grafted NR can repair itself, as evidenced by the small distance between the two fractured samples. The tensile test and microscopic images of NR/4ZDS revealed that it was the best sample among the other vulcanizates. Thus, this study demonstrates the potential of ZDS to induce self-healing ability in NR vulcanizates to extend the limited work done especially ZDS as an ionic cross-linker for self-healing NR.