AState of the Art Review on the Kinetics, Mechanism and Mathematical Modeling of Vulcanization Process in Rubbery Compounds

Vulcanization by heating in the mold is one of the most important steps in the production of rubbery articles. Vulcanization is a time- consuming and expensive process, and quality of vulcanization process has a major role on the final properties of the rubber products. Optimization of vulcanization process time guarantees the quality of products, and it has crucial roles in consumed time, energy and cost. Achieving uniform degree of vulcanization in thicker parts is also another major challenge in the rubber industry. Thus, mathematical modeling and prediction of vulcanization kinetics seem to be of prime importance. The objective of this review paper is to discuss the mechanism and kinetics of sulfur vulcanization of rubber and modeling techniques used as predictive tools. For this purpose, first the kinetics and autocatalytic nature of the vulcanization process is reviewed. Modeling techniques are divided into two categories; phenomenological and mechanistic approaches. Phenomenological models cannot model the whole stages of vulcanization continuously. Moreover, these models do not present the physical-chemistry features of the process. On the other side, mechanistic models have the ability to predict all vulcanization process continuously. In addition, kinetics constants obtained in this approach describe the various stages of the process, physically. Subsequently, models of mechanistic approach which have been introduced so far are discussed in more details.