Insights into self‐healing performance of epoxidized deproteinized natural rubber/graphene oxide composite

The self‐healing performance of epoxidized deproteinized natural rubber (EDPNR) and EDPNR/graphene oxide (GO) composites was investigated. Composites of EDPNR25 and EDPNR50 with GO contents of 0.5 and 1.0 phr were prepared by adding a GO dispersion into a EDPNR latex and the product was subsequently cast into films. Tensile strengths of the original samples and after self‐healing were used to evaluate self‐healing performance. The tensile strength of EDPNR25 after self‐healing achieved about 65% of tensile strength of original EDPNR25. The recovery of tensile strength for the composite increased to 81% for EDPNR25/GO0.5 and 105% for EDPNR25/GO1.0 for self‐healing at 25°C for 24 h. At 70°C, EDPNR25/GO0.5 and EDPNR25/GO1.0 composite achieved ~100% recovery after 24 h. On the other hand, the tensile strength recoveries of EDPNR50, EDPNR50/GO0.5, and EDPNR50/GO1.0 were relatively low (33%, 28%, and 24%, respectively) at 25°C. At 70°C, recoveries increased to 63%, 67%, and 52%, respectively. This result demonstrated that the interdiffusion of epoxidized natural rubber molecules plays a key role in the self‐healing performance rather than hydrogen bonds between GO and functional groups on EDPNR molecules. In this paper, we investigated self‐healing capabilities of epoxidized deproteinized natural rubber (EDPNR) and EDPNR/graphene oxide (GO) composite. We found that increasing GO loadings improved the tensile strength recovery of the EDPNR composite at a certain low epoxy group content. The interdiffusion of epoxidized natural rubber chains, not hydrogen bonds between GO and EDPNR, is the key factor in improving the self‐healing performance for the EDPNR/GO composite.