Fabrication of cis‐1,4 polyisoprene composites reinforced with well‐dispersed silica/carbon black promoted by silica‐rubber hydrogen‐bonding

Abstract Silica is known to be an indispensable ingredient for fuel‐saving tires; however, it has a high tendency to aggregate when compounded with rubber due to component incompatibility. Incorporating hydrophilic groups into hydrophobic rubber would be a promising approach. In the present work, hydroxyl‐modified polyisoprene with high cis ‐1,4 regularity (95.3%–97.1%) and controlled functional fraction (0.5 mol‐%‐28.4 mol‐%) was synthesized via neodymium‐catalyzed coordination‐insertion copolymerization of hydroxyl myrcene with isoprene. Polyisoprene composites reinforced with a hybrid filler of silica and black carbon were then fabricated. Intrinsically promoted filler dispersion in the rubber was enabled through the formation of hydrogen‐bonding between the filler and rubber, verified by variable‐temperature FT‐IR, atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic mechanical analysis (DMA). This interaction is critical to achieving superior integrated properties similar to natural rubber, including stronger tensile strength (25.0 MPa), improved toughness (elongation at break of 1343%), enhanced wet‐skid resistance (tan δ of 0.18), increased rebound resilience, and reduced heat buildup and abrasion. The developed fabrication route offers a feasible solution for constructing well‐dispersed silica‐reinforced composites applicable to energy‐saving green tires. Highlights Hydroxyl‐functionalized essential cis ‐1,4 polyisoprene was synthesized. Hydroxyl functionality reached up to 28.4 mol‐% incorporation. Well‐dispersed silica/carbon black‐filled rubber composites were fabricated. Hydrogen‐bonding promoted silica‐rubber compatibility. The vulcanizates displayed superior integrated mechanical properties.