Mechanism and Kinetics of Sulfonation of Polystyrene−Butadiene Rubber with Chlorosulfonic Acid

The sulfonation kinetics of polystyrene−butadiene rubber (PSBR) with different initial concentrations of chlorosulfonic acid was studied. First, the kinetic study showed that an optimum sulfonation time of 24 h and 1.6 M/mL of chlorosulfonic acid were required for the sulfonation of PSBR to obtain optimum degree of sulfonation. First-order irreversible and first-order reversible models for the reaction kinetics were investigated. The reaction rate was found to obey the first-order reversible model in aromatic ring content due to the effect of HCl produced alongside with the sulfonated rubber. A predictive model was developed, which is able to predict the degree of sulfonation at different initial concentrations of the acid. The simulated results were found to correspond properly with the experimental result with correlation coefficients between 0.991 and 0.997 depending on the concentration of the acid.