Synergistic Network Formation in <scp>SBR</scp> / <scp>ANF</scp> Composites: <scp>GMA</scp> Bridging and Electron‐Beam Crosslinking for Enhanced Strength and Damping Control

ABSTRACT Styrene‐butadiene rubber (SBR) is widely used in tire and damping applications, yet its reinforcement with polar nanofillers is often limited by weak interfacial adhesion in nonpolar matrices. Here, electron‐beam (EB) curing is combined with glycidyl methacrylate (GMA) to promote interphase formation between non‐functionalized aramid nanofibers (ANFs) and SBR without prior ANF surface modification. ANFs were prepared via KOH/DMSO‐assisted fibrillation and incorporated into SBR using a masterbatch route, followed by compounding with GMA and EB irradiation. Process optimization shows that an EB dose of 150 kGy maximizes tensile strength despite monotonic increases in crosslink density with dose, indicating that excessive irradiation (200 kGy) causes over‐densification and/or chain scission that reduces extensibility and strength. FT‐IR evidences epoxy ring opening and consumption of GMA‐associated epoxy/vinyl features after EB curing, consistent with GMA‐mediated coupling at the ANF‐SBR interface. Swelling analysis reveals that crosslink density increases with ANF content only when GMA is present, implying the formation of interfacial networks. SEM fracture morphologies corroborate this interpretation: interfacial voids persist in SBR/ANF controls but largely vanish in SBR/GMA/ANF composites. Under optimized conditions (5 phr GMA, 150 kGy), tensile strength increases systematically with ANF loading, reaching a ~43% improvement at the highest ANF content investigated. Dynamic mechanical analysis shows a reduced tan δ at T g , indicating restricted chain mobility associated with enhanced interfacial interactions and increased crosslink density.