Performance comparison of various surface modifying agents on properties of silica-filled chloroprene rubber

Influence of the surface modifying agents (SMAs) polyethylene glycol (PEG), 3-aminopropyl triethoxysilane (APTES), and bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) on properties of silica-filled chloroprene rubber (CR) was investigated. Results reveal that the presence of SMAs greatly improves mechanical and dynamic properties of the silicafilled CR because of the reduced filler-filler interaction and improved rubber-filler interaction as evidenced by the Payne effect and bound rubber content results, respectively. When compared at the same SMA dosage, TESPT gives the best overall vulcanizate properties. This effect is attributed to high coupling efficiency of TESPT and its ability to donate sulfur atoms during vulcanization, leading to the improved filler dispersion, rubber-filler interaction, and cross-link density. APTES gives high coupling efficiency, but because of the lack of sulfur atoms, its performance is slightly inferior to that of TESPT. In contrast, PEG can only reduce filler-filler interaction, with no significant impact on rubber-filler interaction and cross-link density; therefore, PEG provides lower property improvement.