The influence of temperature and storage time of polymeric sulfur from different producers on its behavior in rubber compounds was studied. Also, the influence of activation by neutron irradiation on a quantity of an insoluble fraction in polymeric sulfur was investigated. To better understand the reason of the small difference in properties of tested polymeric sulfur, its topological structures were evaluated using a thermomechanical method. It was confirmed by a previous conclusion that these kinds of polymeric sulfur have very similar topological structure, and as a result, their behavior in rubber compounds should be practically the same. Studying the reason of blooming in the mineral sulfur it was found that at normal storage conditions, sublimation and oxidative degradation of soluble sulfur could be negligible. For these measurements radioisotopic methods were used.

An analysis of phase diagrams for alloys of components of sulfur-based rubber-vulcanizing systems permitted the calculation of weight ratios and melting temperatures of their eutectic alloys. From Mukhutdinov studies it is known that the formation of a simple eutectic alloy of chemical additives makes possible the reduction of their concentration in sulfur-based vulcanizing systems without decreasing, or even while increasing, their effectiveness. However, to create eutectic alloys, these additives should be in adequate concentration and dispersed within rubber compounds. Therefore, as a successive step of this investigation, zinc stearate dispersion was determined using the radioisotopic method. For this purpose a typical tread-rubber compound with a radioactive zinc stearate (containing 65 Zn) was prepared, and then the ␥ radiation intensity from the rubber samples was measured to determine the zinc stearate dispersion. There wasn't a uniform distribution of this additive within the rubber compound. It was found that zinc stearate doesn't bloom from the compound at a 3% concentration. Also, oil dispersion in different sulfur granules was determined by an ultrasensitive CCD camera. It had been employed to monitor the surface intensity of an ultraweak chemiluminescence of oil in sulfur subjected to oxidative deterioration stimulated by ozonization. The tested samples of soluble sulfur were oiled uniformly, but the polymeric sulfur samples were not. Thus, the probability of creating eutectic alloys with such kinds of sulfur during rubber compounding and processing depends on their local concentration of oil.