PhD thesis defence Anmol Aggarwal

This thesis explores structure – property relationships in silica-filled rubber compounds for passenger car tire treads. The work focuses on how polymer microstructure, functionalization, blend ratios, and filler loading influence rheological, mechanical, and dynamic properties, with the goal of balancing rolling resistance, wet traction, and abrasion resistance – the “magic triangle” of tire performance. Using solution styrene–butadiene rubber (SSBR) and butadiene rubber (BR), both single-polymer and binary blend systems were systematically studied. Key findings show that polymer functionalization enhances filler-polymer interactions and silica dispersion, reducing hysteresis and improving rolling resistance. Blending SSBR with BR provided a synergistic improvement in elasticity, wear resistance, and traction. Laboratory-scale correlations confirmed that LAT100 is a reliable predictor of wet grip and abrasion. The optimal formulation – functionalized SSBR 4602 blended with BR (70/30) and filled with 75-80 phr silica – achieved a well-balanced performance, offering practical design guidelines for next-generation high-performance tire tread compounds.