Synergistic Modulation of Network Architecture and Interfacial Interactions in Chloroprene Rubber Nanocomposites for Ultrahigh Dynamic Durability

Chloroprene rubber (CR), with superior chemical stability and damping properties, exhibits inadequate dynamic performance that constrains its service life. Herein, a synergistic modulation strategy integrating polymer networks, filler networks, and interfacial interactions is proposed for CR-based nanocomposites with ultrahigh dynamic durability. A series of chain-end-functionalized trans-1,4-poly(isoprene-co-butadiene) copolymers (F-TBIR) with varying amine-capped efficiency (CE, 20–52 mol %) and adequate crystallinity were synthesized. Then the structure and properties of CR/F-TBIR (90/10) blends were systematically investigated. The results indicated that both the CR-F-TBIR phase interactions and the rubber–filler interactions increased obviously with the increase in the CE of F-TBIR. These were reflected in the gradually reduced difference in glass-transition temperature (ΔTg) between CR and F-TBIR, further decreased F-TBIR domain size, more blurring phase interface and the increased bound rubber content in the CR/F-TBIR compounds with the increase in CE of F-TBIR. A much better filler dispersion was observed in the CR/F-TBIR vulcanizates with the increase in CE of F-TBIR. When compared with the CR vulcanizate, CR/F-TBIR vulcanizates demonstrated significantly improved dynamic fatigue resistance and almost unchanged damping properties. Notably, the CR/F-TBIR3 (CE = 52 mol %) vulcanizate exhibited a 265% higher crack-initiation flexural fatigue lifetime and a 24% higher tensile fatigue lifetime. The correlations between structure and properties, as well as the mechanism for the significantly improved dynamic fatigue properties of the CR/F-TBIR3 composite, were proposed. The facile and readily implementable blending strategy that incorporates a minor component of crystalline F-TBIR enables the fabrication of high-longevity CR-based nanocomposites for dynamic sealing and vibration damping applications.