Reprocessable and Recyclable Self-Healing Natural Rubber/Carbon Black Composite Based on Metal Thiolate Ionic Network

Reprocessable and recyclable self-healing rubber composites were fabricated by mixing natural rubber (NR) with carbon black (CB) filler in the presence of zinc thiolate (ZT) to form the ionic association in the rubber system. This work investigated and compared the unfilled and natural rubber filled with 5phr of carbon black. The recycling process was repeated three times, and the mechanical performance was measured each time. Tensile strength was increased by more than 430% for unfilled rubber and 520% for NR/5CB composites after the third recycling process. Tear strength was also increased with the number of the recycling process. According to a welding test ability, the developed materials showed potential for repair. Scanning electron micrographs revealed that as the recycling number increased, the white spot of ZT responsible for generating the ionic network reduced as more ZT was converted into Zn2+ salt bonding.