Study on the fatigue resistance of natural rubber with SiO₂ microspheres

SiO₂ microspheres (N98) is a kind of spherical silica with a microstructure of 200 ~ 400 nm. In this work, different silane coupling agents were used for modification of N98 through wet mixing process. 3-(Trimethoxysilyl)propyl methacrylate (KH570) was the modification agent for modifying N98 through the comprehensive analysis of the curing property, Mooney viscosity, hardness, tensile strength, tear strength and fatigue properties of NR/N98 composites. The proportion of KH570 to N98 was further optimized and its modification effect was analyzed by FTIR and SEM. The effects of untreated N98 and KH570 treated N98 (N98@KH570) on the fatigue resistance of NR were mainly studied, and the effects on the basic properties of NR/N98 composites were comprehensively studied. The results show that N98@KH570 powder has no effect on the curing property, tensile property and wear resistance of NR/N98 composites, but can increase the viscosity of Mooney, reduce the tear strength, and slightly increase the hardness of NR/N98 composites. Nevertheless, N98@KH570 is compounded with NR, and the fatigue property of NR is improved. However, the fatigue property of NR can be significantly reduced by NR compounded with untreated N98. The fatigue resistance of NR is gradually improved with the proportion increase of KH570 to N98. The mass ratio of N98 to KH570 is 10:1 and loading of N98@KH570 is 8 phr, the fatigue resistance of NR is improved 71.4% compared with that of the untreated NR/N98 compounds.