Study On Fatigue Behavior Of Aramid Fiber/Styrene Butadiene Rubber Composite

Under the service environment of alternating stress(strain),the fatigue property of rubber material determines the service life of rubber material.The mechanical properties,fatigue behavior and mechanism of carbon black(CB)/styrene butadiene rubber(SBR)reinforced by arrayon fiber(AF)were studied.Aramid fiber respectively for thermal oxidation treatment,Li Cl complexation and Na OH,making AF surface activation and increasing the surface roughness of AF,with butyl pyrazole latex respectively at the same time,domestic liquid rubber.Silane coupling agent(KH560)as a binder processing AF interface,based on the mechanical properties and characterization of fatigue performance test,analysis the changes of modified composite material interface performance.The specific contents are as follows:(1)The effects of AFs with different interface characteristics on mechanical properties and fatigue crack propagation rate of SBR/CB composites were investigated.Fiber influence parameter calculation,power law crack growth rate and the relationship between tearing energy and puts forward the evaluation of AFs fatigue crack growth rate of comprehensive effect,results show that under the condition of low strain fatigue,AF reinforced composites of crack propagation rate is higher than the SBR/CB,but,with the increase of strain fatigue crack propagation rate was lower than that of SBR composite/CB.The influence mechanism of fiber on composite material during crack propagation is presented.At the same time,the interface between the fiber and the matrix has an effect on the fatigue properties of the composites.Although the difference of static mechanical properties is small,the coating of VPL on the AFs surface increases the attraction of the flexible interface layer to the fatigue crack and effectively inhibits the fatigue crack growth.The crack tip of a small notch develops slowly at a lower fatigue strain energy,and the crack tip tends to passivate as the strain increases.(2)The effects of different modifications on mechanical properties and fatigue properties of fiber-reinforced styrene butadiene rubber composites were studied.The differences of static mechanical properties and fatigue crack propagation caused by different fiber orientations were characterized.The change of RDE before and after fatigue was investigated.MLPB can not only enhance the interfacial strength of the composites,but also increase the adhesion between the fibers and the matrix,and effectively improve the inhibition of the fibers on crack propagation.The static mechanical properties and dynamic fatigue properties of composites are obviously affected by the different orientation of fiber,and the interface between fiber and matrix has little correlation with the properties of composites when the fiber is vertically oriented.With the fiber vertical orientation,the stress-strain curve deviated significantly and the RDE value decreased after the fatigue of notched composite samples.When the fibers are oriented in parallel,the stress-strain curves of composites before and after fatigue have no obvious change.(3)In this chapter,the effects of different characteristic interfaces formed by coupling agent KH560 and butadiene latex VPL on the mechanical properties of composites are studied,and the stress variation trend of composites during fatigue crack propagation is also studied.Both KH560 and VPL can improve the interface strength of composite materials,and both the 100% and 300% tensile stresses are improved.However,in terms of dynamic mechanical properties,the ductile interface layer formed by VPL can absorb more energy,and the interface damage resistance is better.