Effect of Vapor-Grown Carbon Nanofibers on the Sliding Friction of Natural Rubber Composites

The friction properties of vapor-grown carbon nanofibers (VGCFs) reinforced natural rubber (NR) composites were investigated with the ball-on-plate sliding test. A mechanism was proposed on the basis of the viscoelastic properties, morphology and hardness of the composites, determined using dynamic mechanical analysis, optical microscopy, field emission scanning electron microscopy, transmission electron microscopy and a hardness-testing device. The friction behavior of NR/VGCF composites showed three different stages: an increment trend at first stage, a decrement trend at second stage and a stable state at third stage. The peak values of friction coefficient were similar, and the peak shifted to a smaller cycle with increased VGCF content. The eventual friction coefficient decreased with increased VGCF content due to accelerated formation of abrasion patterns in the NR/VGCF composites. Moreover, the arranged VGCFs contributed to the self-lubrication of NR/VGCF composites and the NR/20 wt% VGCF composite had the smallest friction coefficient. POLYM. COMPOS., 32: 675-681, 2011. (C) 2011 Society of Plastics Engineers