Hydrogen bonding network formation in epoxidized natural rubber

Reversible networks of epoxidized natural rubber (ENR) mixed with dicarboxylic acid were studied. ENR is a bio-based polymer, commercially available, and capable of sulphur vulcanisation. In addition, ENR has been already reported to exhibit self-healing characteristics after ionisation by adding ionic groups to the epoxide group. The reversible network structure plays an essential role for self-healing behaviour, which cannot be obtained for elastomers with irreversible sulphur network. In this study, dicarboxylic acid was used to construct the reversible network. The reversible hydrogen bonds were established in such a way that firstly one carboxyl group of di-carboxylic acid (DA) is reacted to ENR and secondary the other carboxyl group of DA interacts with residual carboxyl group to form hydrogen bonds in carboxylic dimer. The self-healing behaviour was evaluated for ENR with DA by tensile tests. This self-healing system provides new insights for sustainable and natural-based materials.

Automated summary

This study investigated the reversible network structure of epoxidized natural rubber (ENR) mixed with dicarboxylic acid. ENR is a commercially available, bio-based polymer capable of sulphur vulcanisation. The addition of dicarboxylic acid allowed for the formation of reversible hydrogen bonds in the network, providing self-healing characteristics. This research introduces a new approach for sustainable and natural-based materials.