Influencing factors for vulcanization induction period of accelerator / natural rubber composites: Molecular simulation and experimental study

Sulfonamide accelerators are one of the most widely used additives in rubber composites since they can significantly improve the rate of vulcanization process. However, usually the vulcanization induction period of the composites containing sulfonamide accelerators maybe too short, which leads to great potential safety hazards during manufacture process. Combining with experimental and molecular simulation methods, factors affecting the vulcanization induction period could be subdivided into the following items, i.e., the reactivity, the alkalinity, the solubility, the mobility and binding energy of accelerator in rubber composites. It was found that the chemical reactivity of accelerator is the key factor to affect the vulcanization induction period, and the well-dispersion and stability of accelerator in natural rubber could promote the vulcanization induction period reaction. This work may help us better understand the vulcanization induction period influencing factors from a micro-level perspective, and attempts to provide a guidance for screening and design of the new sulfonamide accelerators.