Effect of neodymium stearate on cure and mechanical properties of epoxidized natural rubber

The effect of neodymium stearate (NdSt) on cure and mechanical properties of expoxidized natural rubber with 25 mol.% epoxidation (ENR25) was studied in the concentration range of 0 to 2 phr, and the relationship between structure and mechanical properties of ENR25 vulcanizates was also discussed. Neodymium sterate was synthesized by saponification of stearic acid with newly formed rare earth hydroxide in water medium, and the structure of NdSt was investigated by Fourier transform infrared spectroscopy (FTIR). Crosslinking density of vulcanized natural rubber was studied by equilibrium swelling method. The results indicated that the interaction force between carboxylic ion of NdSt prepared in the lab and Nd ion was mainly ionic bond through FTIR analysis. NdSt could accelerate the vulcanization of ENR25 and influence the network structure of ENR25 vulcanizates. The incorporation of 1 phr NdSt for ENR25 vulcanizates showed the optimal aging resistance.