Use of borax as a crosslinker in Epoxidized Natural Rubber

The aim of this work is to study the use of borax as a crosslinker in  epoxidized natural rubber (ENR) and investigate the influence of borax content (0, 10, and 30 phr) on the ENR properties. The FTIR and ¹¹B-NMR spectra revealed the formation of a borate-ester bond between ENR and borax. The effect of the amount of borax on crosslinked density and gel content was studied through an equilibrium swelling experiment. The results indicated that both crosslinked density and gel content depended on the amount of borax. The crosslinked density and gel content were improved by 2.5 times and 1 time when 10 phr borax was added in ENR. Furthermore, the crosslinked network between borax and ENR enhanced ENR's self-healing properties. These results exhibited that borax could be an alternative crosslinker in self-healing rubber applications.