Study on self-healing natural rubber based on reversible Zn2⁺ salt bond network

Self-healing  materials have broad application prospects in the fields of healthcare and bionic materials. In this study, a self-healing rubber was developed using natural rubber as the matrix and zinc diethyldithiocarbamate (ZT) as the filler, with a reversible Zn²⁺ salt bond cross-linked network serving as the primary structure. The relationship between the self-healing ability of the composite and the density of the reversible Zn²⁺ salt bond cross-linked network was investigated by varying the ZT filler content. Additionally, the effect of different healing temperatures on the material's self-healing performance was explored. The results showed that when the ZT filler content was 30 phr, the ionic cross-linking density reached its peak, resulting in optimal mechanical properties and healing efficiency, with a tensile strength recovery efficiency of 51.9% and a tear strength recovery efficiency of 72%. As the healing temperature increased, the repair efficiency of the material gradually improved, peaking at 150 °C, where the tensile strength recovery efficiency reached 88.2% and the tear strength recovery efficiency reached 123.2%. This phenomenon was attributed to the enhanced molecular chain mobility at higher temperatures, which accelerated the formation of new ionic cross-linked networks. Furthermore, it was found that the improvement in self-healing ability significantly enhanced the material's fatigue resistance. This study provides potential value for the research and development of self-healing materials in practical applications.