Failure resistance and vibration isolation in natural rubber composites: role of matrix- and filler-dominated viscoelastic loss

Viscoelastic dissipation governs both vibration attenuation and fatigue durability in rubber components; however, the role of its physical origin in determining engineering performance remains unclear. This study establishes a unified mechanistic framework to distinguish matrix-dominated and filler-network-dominated dissipation pathways using four natural-rubber-based compounds: unfilled NR, an NR–ENR blend, and NR reinforced with N220 and N772 carbon blacks. Mechanical properties, dynamic mechanical behavior, Payne effect, heat build-up, tear resistance, fatigue crack growth, and vibration transmissibility were systematically evaluated. The results reveal that NR–ENR achieves enhanced damping through molecular relaxation and intermolecular interactions, increasing the loss factor by 112.5% and reducing resonance transmissibility from 6.3 to 3.1, while maintaining excellent fatigue resistance with no complete crack growth after 8 × 10 5 cycles. In contrast, filler-network dissipation, governed by network breakdown/reformation and interfacial friction, improves static reinforcement but induces higher hysteresis and heat accumulation, accelerating fatigue failure. These findings demonstrate that damping magnitude alone cannot define rubber component performance; instead, vibration isolation, thermal stability, and durability are controlled by the underlying energy dissipation mechanism and its associated energy redistribution pathway.