The Mechanism of Accelerator Action

Publisher Website
Google Scholar
Abstract
In the year 1839, Goodyear discovered that, on treatment with sulfur at elevated temperatures, natural rubber loses its plasticity and becomes elastic. Around the time of World War I, it was discovered that the reaction of the sulfur with the unsaturated rubber hydrocarbons could be promoted by the action of so-called vulcanization accelerators. The reaction then takes place not only faster and at lower temperatures but, in addition, one also needs less sulfur and the vulcanizates acquire considerably better technical properties. Accordingly a tremendous number of compounds have been examined as accelerators of vulcanization and much effort has been applied to develop accelerators with the most satisfactory properties. Today, accelerators are known which permit vulcanization at room temperature. In the past, the mechanism of accelerator action has been studied mostly with the methods of organic and physical chemistry. In the following, an attempt will be made to consider the problem from the viewpoint of the inorganic chemist. One can attempt to interpret the catalysis from two points of view. Either the reactivity of the unsaturated natural rubber hydrocarbon is enhanced, or the sulfur will be converted into a more reactive form. Twiss concluded from his investigations that the latter possibility is the more likely. Subsequently, this assumption has been supported by further observations. In particular, the discovery of Peachey pointed in this direction, since natural rubber is vulcanizable at room temperature if it is treated successively with hydrogen sulfide and sulfur dioxide gases. The sulfur which is formed by this reaction is in the nascent state and is very reactive.

This publication has 0 references indexed in Scilit: