Research Of Fatigue Properties Of Graphene Oxide/Rubber Nanocomposites

Rubber fatigue is a process that the physical properties of rubber production decrease gradually. Resist fatigue properties are closely related with rubber safety and reliability in life production. Graphene oxide (GO) is considered a kind of fillers putting into rubber matrix that can improve resist fatigue properties effectively, as a newly two-dimensional carbon material. This paper is mainly to study the effect of GO on rubber fatigue properties, and analyze the mechanism of GO, from two vision of uniaxial tensile fatigue and pure shear fatigue.Hummers method was utilized to prepare GO in first section of paper, and a series of characterization, such as FTIR、XRD、XPS、Raman、TGA and AFM, proved that distance between GO layers had increased and oxygen functional groups had been grafted successfully on the surface. GO can stay steadily without any deposition and aggregation.Uniaxial tensile fatigue properties of GO/silica/SBR nanocomposites had been researched in second section. It turned out that torque of curing curve, initial storage modulus of mixture, loss factor of vulcanizates and mechanical properties tended to increase, on the contrary, glass-transition temperature and loss factor tended to decline, with the increase of GO. For samples with variable fatigue cycles, fillers had dispersed more uniformly and GO had orientated along the stress direction. Fracture surface of fatigue samples was less coarse and fracture route was less complicated compared with unfatigued samples. Crosslink density descent range was decreased gradually with the increase of GO loading. Tensile strength of samples with fatigue 50 thousand cycles improved, elongation at break decreased, and glass transition temperature and loss factor sort of increased, compared with that after fatigue 20 thousand cycles. S-N curves and SED-N curves revealed that fatigue life would increase when GO loading increased. All of those phenomenon were related with the orientation of two-dimensional structure GO, which would consume much more energy during the whole process.Pure shear fatigue properties of GO/SBR nanocomposites had been researched in third section. It found that, for pure SBR material, the smooth extent was similar for both unfatigue and fatigue sample, which revealed bad properties. When tearing energy was beyond 1500J/m2, crack growth rate would increase quickly and unsteadily. For GO/SBR material, with the increase of fatigue cycles, GO went through a newly-dispersed process, and GO tended to get orientation along the stress direction. Meanwhile, micro structure fracture began to show up sections became smooth gradually after later fatigue period. Crosslink density began to decrease obviously when fatigue cycles were beyond 400 thousand times. Crack growth rate of variable fatigue cycles samples went through an up-down-up process.Pure shear fatigue properties of GO/silica/SBR nanocomposites had been researched in forth section. It found that, with the increase of silica loading, initial modulus of mixture, glass-transition temperature, and mechanical properties increased gradually, while loss factor of DMA decreased. Crack growth rate of three kind of unfatigue samples almost kept identical in the range of 1500 J/m2 tearing energy. GO/silica/SBR samples were fatigued variable cycles separately at low strain and pure shear model; the results showed that the dispersion of fillers was getting better and better, and GO got orientation. The fracture section of samples tended to be smooth. Crosslink density seemed to decrease after 200 thousand fatigue cycles. When fatigue cycles were below 400 thousand cycles, and tearing energy was below 1000J/m2, crack growth rate of variable fatigue cycles samples was basically identical. When fatigue cycles were beyond 600 thousand cycles, crack growth rate increased quickly and unsteadily.