Hierarchical nanoclay–glass fiber hybrid reinforcement for improved fatigue life in rubber V-belts

Abstract

The service life of industrial V-belts is often curtailed by fatigue failure under cyclic loading. In this work, a styrene–butadiene/polybutadiene/smoked rubber (SBR/PBR/SMR) blend was reinforced with 5 phr Cloisite® 15A nanoclay and 5 phr short A-glass fibers. The composite was processed via Banbury mixing, calendaring, layering with PET cord, and vulcanization. Rheological analysis revealed distinct filler effects: short glass fibers (SGF) yielded the fastest cure rate (CRI), while the hybrid system achieved the highest final crosslink density ( $\mathrm{\Delta }M$ ). Compared to the unfilled compound, the hybrid composite exhibited superior performance, including a 29% increase in tensile strength, a 14% improvement in abrasion resistance, and a 79% rise in glassy storage modulus ( $E_{glassy}^{\prime }$ at −80°C). Dynamic mechanical analysis (DMA) confirmed this reinforcement through a higher glass transition temperature ( $T_g$ ) and revealed that the hierarchical filler network maximized energy dissipation (highest $\mathit{tan}\hspace{0.17em}{\delta }_{\mathit{max}}$ ), establishing a direct, quantitative link to fatigue performance. Consequently, the compound’s fatigue life increased by 42% (from 1.30 × 10⁵ to 1.85 × 10⁵ cycles), which translated directly into a 40% extension of the V-belt’s operational life (from 100 to 140 h) under multi-pulley dynamic testing. This work establishes a validated framework demonstrating that engineering viscoelastic and interfacial properties at the material level is a powerful strategy for developing more durable power transmission belts.

Graphical Abstract