From Devulcanization of Ground Tire Rubber by Microwaves to Revulcanization: A Revulcanization Kinetic Approach Using a Simple Prediction Model
Fabiula Danielli Bastos de Sousa, Heitor Luiz Ornaghi
Abstract
Devulcanization of rubber by microwave energy is an environmentally friendly technique, and it has gained special attention from the recycling field due to several advantages over other methods such as high productivity, uniform heating, and the noninvolvement of chemicals during the process. In this sense, ground tire rubber (GTR) was devulcanized by the action of microwaves at different exposure times. The thermal stability of devulcanized samples and the revulcanization behavior were correlated to structural modifications that occurred during devulcanization. The revulcanization kinetics by Arrhenius parameters was studied aiming at determining the mechanism and model of the reaction, being that it seems to follow an autocatalytic mechanism with a revulcanization model type reagents → products. The optimization of the temperature and time of the revulcanization process was determined based on five initial temperatures. The predicted results were based on previous revulcanization kinetic parameters, and they were physically plausible with the data, mainly within the studied temperature range. A more developed understanding of the chemical structure/reactions is recommended to avoid errors of interpretation out of the studied experimental range. Finally, the obtained results are new, allowing the prediction and optimization of kinetic properties such as the revulcanization process, being essential to the development of microwave devulcanization as a truly sustainable recycling process.