Microstructure of uniaxially fatigued thermally aged vulcanised natural rubber filled with cerium oxide

The effects of a cerium oxide (CeO2) filler on the fatigue properties of heat-aged vulcanised natural rubber (NR) were tested and analysed. The vulcanised NR specimens, filled and unfilled with CeO2, were heat-treated for 24 h. Uniaxial fatigue tests were performed on the two specimens under different strain amplitudes, and the microstructures of the fracture surfaces of the specimens were analysed using scanning electron microscopy. The results show that filling with CeO2 improves both the ageing resistance and fatigue resistance of the material. Notably, CeO2 has good dispersibility in the matrix, improves the internal network structure of the rubber, and enhances the interactions between the molecular chains of the rubber. The fatigue fracture surfaces of both materials have a fish-scale-like appearance, indicating ductile fracture, but the CeO2-filled heat-aged vulcanised NR has a smoother surface, better wettability of the filler, and longer fatigue life.