Influence of dispersibility of complex vulcanization activator on properties of rubber mixtures and rubbers

In the study of experimental complex vulcanization activators with a reduced content of zinc oxide, obtained on the basis of bentonite. The properties of rubber mixtures, vulcanizates obtained with the use of vulcanization activators of various fractional composition have been investigated. The granulometric composition and the content of volatile substances in various bentonites have been studied. Based on the data obtained, bentonite was selected and an experimental vulcanization activators was synthesized. The synthesis of a series of experimental vulcanization activators with bentonites of different fractions was carried out in accordance with the developed methodology. During the grinding and subsequent fractionation of experimental vulcanization activators, experimental products with a particle size of 0.1 to 1.4 mm were obtained. The vulcanization properties of rubber compounds based on SKI-3 isoprene rubber, elastic-strength properties were studied, and the vulcanization constants were calculated. During the tests of rubber compounds obtained using various fractions of an experimental complex vulcanization activator, it was revealed: a decrease in the time of the optimum vulcanization to 27 % (compared to the comparison sample) with a slight decrease in the time of the onset of vulcanization. The reduction in torque was noted. Analysis and strength rubbers showed that the relative tensile strength of the prototypes exceeded the reference one by 20-40%. The elongation at break in the experimental rubber is 50-80 % higher than that of the serial sample, which indicates the formation of a more uniform vulcanization network in the experimental products. It has been established that experienced vulcanization activators with a reduced content of zinc oxide with particle sizes from 1 to 0.2 mm provides the best complex of physical and mechanical properties and can be recommended for practical use in the composition of rubber compounds, which will reduce the content of zinc oxide toxic to the environment.