Effect of Maleic Anhydride and Glyceryl Methacrylate Cografted Reclaimed Rubber on Improving the Performance of Styrene–Butadiene Rubber/Silica

Thermoplastic desulfurized reclaimed rubber is a low-cost and environmentally friendly material. However, its complex composition and severely reduced molecular weight can impair the performance of rubber products when blended with other rubbers. Silica is currently the primary filler for producing green tires, owing to its environmentally friendly comprehensive performance. However, achieving uniform dispersion of high silica content in nonpolar rubbers, such as styrene-butadiene rubber (SBR), remains challenging owing to the strong interactions among polar silica particles. Herein, desulfurized natural reclaimed rubber (NRR) was modified by simultaneous grafting with glyceryl methacrylate and maleic anhydride, which can form significantly stronger interactions with polar silica via hydrogen bonding, improving the processing performance and mechanical properties. Compared to ungrafted SBR/silica/NRR composites, the grafted SBR/silica/NRR composites improved the tensile strength (15.8%), elongation at break (33.8%), tear strength (2.4%), and modulus at 100% elongation (3.3%) while reducing fatigue heat generation. Through this cografting modification, the obviously reduced elongation at break caused by the addition of unmodified reclaimed rubber was highly improved. This modification strategy enables high-value reuse of reclaimed rubber.