Synthesis of nano zinc hydroxide via sol–gel method on silica surface and its potential application in the reduction of cure activator level in the vulcanization of natural rubber

Abstract

In this article, we have described the synthesis of nano zinc hydroxide on the surface of precipitated silica via the sol–gel precipitation method. The studied zinc hydroxides have been tested as novel cure activators on the vulcanization of natural rubber. The aim of this paper was to reduce the cure activator level in the vulcanization of natural rubber. Synthesized zinc hydroxides were characterized by Fourier transform infrared spectroscope, X-ray diffraction, and field-emission scanning electron microscope, and the results clearly indicate the formation of nano zinc hydroxide with a plate-like structure on the surface of silica. Curing and tensile properties in the presence of synthesized zinc hydroxides as cure activator were compared with those of conventional zinc oxide as a cure activator on the vulcanization of natural rubber. The curing study indicated that lowering the concentration of zinc hydroxide on the silica surface improves the cure rate index to a large extent and it is greater than 360 % for 0.18 g of zinc hydroxide per gram of silica-accelerated vulcanizates compared with that of conventional 5 g zinc oxide-accelerated vulcanizates. However, lower concentrations of zinc hydroxide form fewer number of cross-links, which merely affects the tensile strength. Considering both curing and mechanical properties, 0.5 g of zinc hydroxide per gram of silica, which was synthesized in this experiment, is the suitable choice for activator for the vulcanization of natural rubber.

Graphical Abstract

[InlineMediaObject not available: see fulltext.]