A Study of the Vulcanization Kinetics of an Accelerated-Sulfur SBR Compound

Vulcanisation kinetics for a SBR compound was studied by using both curemeter and DSC methods by a kinetic approach. A simplidied but realistic model reaction scheme was used to simulate both induction and curing periods simultaneously. Model parameters were extracted from isothermal curemeter experiments. The model prediction demonstrated a good agreement with isothermal curemeter data over a temperature range of 120°C to 180°C. The variation of equilibrium modulus with temperature, observed from cure curves, can also be predicted. However, DSC experiments showed a different reaction behavior in the curing period as compared to model calculations. This was explained by the assumption that the reaction heat observed in DSC is due to all possible exothermal reactions, and the formation ofcrosslinks is only a part of these reactions. Hence, the curemeter can provide a good a indication of crosslink formation, while DSC displays the entire reaction heat released during the vulcanization process. THe kinetic approach allows one to incorporate vulcanisation kinetics into practical simulation of reactive processing operations