In situ generation of sulfur using silica as a carrier in the wet mixing of natural rubber latex

Abstract

AbstractUsing sodium thiosulfate and hydrochloric acid as the raw materials and a silica aqueous dispersion as the carrier, sulfur is generated in situ by a chemical precipitation method, and an in situ sulfur‐silica/natural rubber (in situ S‐Silica/NR) composite is prepared. The in situ sulfur is characterized, and its effects on the natural rubber composites' cross‐linking density, vulcanization characteristics, mechanical properties, aging properties, dynamic mechanical properties, and Payne effect are studied. The experimental results show that the particle size of in situ sulfur is small, with a maximum of 5 μm, and the cross‐linking ability is stronger than commercial sulfur. Due to the strong surface adsorption force of silica, the interfacial bonding strength is enhanced, and the dispersion of the two components in the rubber matrix is improved. Compared with commercial sulfur‐silica/natural rubber (S‐Silica/NR) composites, the tensile strength is 20.3% higher, the elongation at break is 28.5% higher, and it better retains its aging properties and has a lower rolling resistance. This study provides a theoretical basis for the development of functional rubber vulcanizing agents and the preparation of high‐performance rubber composites.