| Strong vibration and harsh noise commonly occur under full-speed running condition for high-speed trains,which not only results in un-comfortability for passengers but also shortens the service life of mechanical component of high-speed train hence increases the economic loss.Therefore,how to effectively control the inner noises and the vibration of high-speed trains coaches has become a critical problem for the development of novel high-speed trains.In order to solve that problems,so far,researchers have conducted the optimization for the system of the whole high-speed railway,and the usage of damping vibration attenuation materials for the key components which has been proved to be an effective method to reduce the noises and the vibration,especially for the rubber damping materials.How to economically and effectively strengthen the dynamic mechanical properties of rubber damping materials is the key point for researchers.In order to improve the overall performance and lower the cost of damping rubber,the addition of filler to tailor the dynamic mechanical property of rubber has many advantages,such as simple process,convenient operation,which can effectively lower produce cost of damping rubber.Given that the addition of filler can increase interaction interface between the filler and the rubber matrix,the more interface will highly increase the friction and then improve the dynamic mechanical property of the composite material during the vibration process.Compared with the traditional macroscopic filler method,the addition of nano-inorganic filler is more prone to increase the interaction of the interface.Thus,this paper selects two kinds of nano-fillers with high specific surface area to prepare rubber composite material.By increasing the interaction of the interface in the matrix,the dynamic mechanical property of rubber is thereby strengthened.According to current literature,since the interaction between the polymer matrix and graphene as well as carbon nanotube is weak,and conglobation can easily be generated in the matrix,as a result of which,instability,like the reduction of the modulus of elasticity and damping value,will occur in the dynamic mechanical property test of the composite material prepared using carbon nanotube and graphene.Therefore,a design method of the functional nano-filler applicable to rubber damping material is put forward in this paper,to improve the dynamic mechanical property of rubber composite material,i.e.,using carbon nano-filler to enhance the friction action of the matrix interface,making high-density modification on the surface of the carbon nano-filler to enhance the polar group and improve the interaction between the filler and matrix,and ensuring the favorable dispersity of the functional filler in the matrix for the modification reagent selected.The functional carbon nano-filler meeting the above requirements will be prepared to enhance the dynamic mechanical property of the matrix.In the paper,two functional carbon nano-fillers were prepared using the design method mentioned above,and the composite material was made for the test and validation.(1)Study on the action of graphene functional filler in enhancing the dynamic mechanical property of carboxylated nitrile rubberIn the paper,graphene intermediate modified by sulfonic ionic liquid was prepared,and the sulfonic ionic liquid was attached in high density to the surface and between layers of graphene,which increased the grafting ratio of silane coupling agent KH550.Two samples with the highest KH550 grafting ratio and the lowest KH550 grafting ratio were compared on the basis of the XPS test: Content of Si element in the sample with the highest KH550 grafting ratio increased by 2.14%,and the corresponding KH550 grafting amount was raised by 41.8%.The dynamic mechanical property test result of the composite material made of graphene functional filler shows that the modulus of elasticity of the composite material was markedly increased in the whole temperature field,and the glass transition temperature of the composite material inclined to a high temperature,and peak value of the dissipation factor of the composite material was increased.After 120℃ aging and oil immersion test,the modulus of elasticity and loss modulus of the composite material were still higher than those of the original sample.The traditional condition tests and the harsh condition tests show that the graphene functional filler using the current design method can reliably and effectively enhance the dynamic mechanical property of the composite material.(2)Study on the action of modified carbon nanotubes functional filler in enhancing the dynamic mechanical property of carboxylated nitrile rubberIn the paper,carbon nanotubes intermediate modified by polydopamine was prepared,and the polydopamine was attached in high density to the surface,which increased the grafting ratio of silane coupling agent KH550.Two samples with the highest KH550 grafting ratio and the lowest KH550 grafting ratio were compared on the basis of the XPS test: Content of Si element in the sample with the highest KH550 grafting ratio was increased by 4.2%,and the corresponding KH550 grafting amount was raised by 181%.The dynamic mechanical property test result of the composite material made of carbon nanotubes functional filler shows that the modulus of elasticity of the composite material was markedly increased in the whole temperature field,and the glass transition temperature of the composite material inclined to a high temperature,and peak value of the dissipation factor of the composite material was increased.After 120℃ aging and oil immersion test,the modulus of elasticity and loss modulus of the composite material were still higher than those of the original sample.The traditional condition tests and the harsh condition tests show that the carbon nanotubes functional filler using the current design method can reliably and effectively enhance the dynamic mechanical property of the composite material.(3)Study on the impact of mixed matrix on the dynamic mechanical property of carboxylated nitrile rubberTwo functional fillers,i.e.,graphene and carbon nano tube,were mixed with carboxylated nitrile rubber based on the emulsion method to study the impact of the synergistic effects of two functional fillers on the dynamic mechanical property of carboxylated nitrile rubber.The synergistic effect ensures that two functional fillers can maintain favorable dispersity in the matrix of carboxylated nitrile rubber,which can enhance the physical property of the polymer material.But such chain structure makes it more difficult to keep the relative slippage between the filler and matrix interface,which causes the damping value to be reduced. |
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