Use of Different Inorganic Activators As Alternative to ZnO in Natural Rubber Vulcanization

Over the years different alternatives have been proposed to reduce the zinc levels in rubber compounds in order to decrease the environmental impact of the rubber industry. Several researches have investigated such us the effect of nano-sized ZnO, different metal oxides, or zinc complexes. In this work, a new approach to reduce the zinc levels is presented. The novel activators that have been synthesized contain lower quantities of zinc in their structure. These species were previously tested using model compound vulcanization with squalene as model molecule for natural rubber and the result found suggested that its use is a very practical way to minimize the total amount of zinc used in rubber compounds. In this study, these activators are tested in natural rubber. The compounds comprising these species show properties similar, and in some cases even superior, properties than compounds with higher amounts of ZnO. The results found indicate that the novel activators allow the reduction of the zinc level in rubber compounds without deteriorating the properties of the final product.