"Effect of lanthanum p-aminosalicylate on vulcanization characteristics of natural rubber"

Abstract

Lanthanum chloride and sodium p-aminosalicylate were used as raw materials to synthesize a new environmental-friendly accelerator lanthanum p-aminosalicylate (PAS-La) by precipitation method. The product was characterized and its mole-cular formula was determined to be La(C7H6NO3)3·H2O by elemental, thermal and infrared spectral analysis. The effects of PAS-La on the vulcanization characteristics, crosslinking density and mechanical pro-perties of natural rubber were investigated using rotorless vulcanzation apparatus, equilibrium swelling method and universal testing machine, and the vulcanization kinetics were analyzed. The results showed that with the increase of PAS-La amount, there was a maximum value of positive vulcanization time of natural rubber, and the scorch time firstly decreased and then increased. The crosslinking density of vulcanized rubber increased, and the mecha-nical properties were significantly enhanced. When PAS-La was added at amount of 1.2 phr (by mass), its vulcanization promotion effect on natural rubber was optimal. Kinetic calculations revealed that the reactivity of the crosslinked precursors was enhanced with the increase of PAS-La amount, and the activation energy decreased first and then increased.

Keywords

• lanthanum p-aminosalicylate， natural rubber， vulcanization accelerator，rare earth，activation energy，