The Influence of Carbon Black Dosage and Type on the Fatigue Failure Characteristics of Rubber Materials

This study investigates the effects of carbon black dosage and type on the fatigue failure characteristics of natural rubber (NR) materials. By conducting tests on fatigue life, fracture energy density, and tensile fatigue curves across rubber samples with varying carbon black dosages and types, and complementing these with scanning electron microscope (SEM) analysis of the fracture surface microstructure, we reveal the influence of carbon black particle size and structure on the fatigue life of rubber. The results indicate that the amount of carbon black filler significantly affects the fatigue life and fracture energy density of the rubber; higher filler content is associated with reduced fatigue performance. Smaller carbon black particles, due to their propensity to entangle during processing, exhibit poorer dispersion. Furthermore, carbon blacks of different particle sizes and structural degrees display distinct failure modes within the rubber matrix. Notably, N375, characterized by a relatively moderate particle size and structure, markedly enhances the rubber's fatigue resistance. By establishing a model of the rubber fatigue failure process, this research elucidates the evolving mechanisms of filler particles, micro-defects, and the internal structure of the rubber during fatigue, thereby providing a theoretical basis for optimizing the fatigue life of rubber materials.