Zur Kinetik von Bildung und Abbau polysulfidisch gebundenen Schwefels bei Vulkanisationsprozessen

Abstract

The polysulfidic bound sulfur in vulcanization processes shows a maximum over the reaction time and therefore can be regarded as an intermediate. For its increase and decrease a kinetic theory is developed. According to this, the dependance of polysulfidic bound sulfur upon reaction time can be calculated in good agreement with the experiment. The employment of the kinetic theory outlined is restricted to first order kinetics of sulfur decrease and decrease of polysulfidic bound sulfur. The formation of end products, being the result of consecutive reactions, could also be calculated. All theoretical consequences could be improved by employing an empirical formula by which the dependance of polysulfidic bound sulfur upon reaction time could be described.
The agreement between theory and experiment was shown by the vulcanization of natural rubber by sulfur accelerated by ZnO, zinc-mercaptide and zinc salts of fatty acids, the temperature and the concentration of the reactants being parameters.