| It has been accepted that the noise radiation is induced by the vibration of objects.The vibration of structures could be inhibited effectively by means of the excellent damping materials which are considered to be the most suitable ways among of measures.In this way,not only could solve the noise pollution problem,but also improve operational precision and the service life.So,many products about excellent damping materials have been developed and industrialized.Damping materials could be divided into asphalt damping materials,damping coatings as well as rubber damping materials in accordance with the different polymer matrixes.The asphalt damping material,having low cost and convenient preparation,has been used widely in various industries over the years,such as cars.However,this kind of damping materials has been not used in the high performance requirements because of its pungent smell and cancer-causing problem.In contrast,rubber damping material has these advantages.Optimum damping property is concentrated on the low-temperature(high frequency area).Nevertheless,at the room and high temperature(low frequency regions),the damping performance is not good.So,rubber damping materials usually needs to be modified for the purpose of broadening used ranges.The fillers is the important.part of rubber material,not only for reduce the cost,but also enhance the mechanical properties,in the past,people always focus on the carbon black or the fibers,there is few study on the two-dimensional fillers,This paper will work on this background,resorted to the dynamic mechanical analysis(DMA),Cantilever method,scanning electron microscopy(SEM),Infrared Spectroscopy(IR),x-ray diffraction(XRD),differential scanning calorimetry(DSC)and so on.The damping mechanism,thermal stability and measures to improve thermal stability of NBR hybrid damping material were studied.The main contents and conclusions are as follows:(1)Study of the two-dimensional fillers on the dynamic mechanical properties of NBRBecause the damping mechanism of two-dimensional fillers in damping materials was not clear recently,by means of dynamic mechanical performance Analyzer(DMA),differential scanning calorimetry(DSC),and Fourier Transform Infrared Spectra(FT-IR)and Scanning Electron Microscopy(SEM),the pulvistalci,graphite and sericite in the NBR were carried out and the conclusions were as follows:three kinds of flake fillers all have a very good enhance effect,sericites in the NBR matrix has a good compatibility,the enhancement effect is larger than the others,graphite has a good lubricity,it can play a role of strengthening and will have a beneficial effect on the energy dissipation of matrix,the aggregation is an important factor of the damping properties.(2)The study of flake fillers in hybrid damping materials on the dynamic mechanical propertieshybrid damping material is new kind of damping materials,using fillers to enhance it is very important.by means of dynamic mechanical performance Analyzer(DMA),differential scanning calorimetry(DSC),and Fourier Transform Infrared Spectra(FT-IR)and Scanning Electron Microscopy(SEM),The results suggest that after the addition of the graphite,the tangent of loss angle(tan δ)),the storage modulus(E’)and loss modulus(E")all present a trend which increases and then decreases when the content of graphite increases.By the time the content of graphite reaches its critical value(mass ratio:10%),the dynamic mechanic property such as tamδ,E’,E" would have a better performance.According to the fourier transform-infrared spectrum analysis,hydrogen bonding effect is not the key factor to the dynamic mechanic property of ternary blends system.In fact,it has great correlation to the characteristics of graphite itself as well as the formation of microstructure within the blends which results from the interaction between FG and AO-2246-NBR blends,the sericite in NBR/AO-2246 is more uniform than that in NBR,and the destruction of small molecule hybrid hydrogen bond system is more serious,and the enhancement effect is not as good as the other two kinds of fillers.(3)The study of flake fillers in organic-inorganic hybrid material on the dynamic mechanical propertiesIn the work,new type composites of acrylonitrile butadiene rubber(NBR)and polyurethane-sericite(PU-sericites)hybrid materials was prepared by melt blending method,by means of dynamic mechanical performance Analyzer(DMA),differential scanning calorimetry(DSC),and Fourier Transform Infrared Spectra(FT-IR)and Scanning Electron Microscopy(SEM),the result shows:It was indicated by dynamical mechanical analysis that the damping property of NBR decreases as the amount of PU increases,whereas the mechanical properties at low temperature are enhanced.When PU of 10 w%was added in,a better damping property can be obtained._The damping property of NBR PU composites would decrease when adding in sericites,however,the mechanical properties at low temperature would be improved.With PU-sericites hybrid added,the compatibility between sericites and NBR/PU composites would be enhanced and the quasi-interpenetrating polymer network structures would be formed,resulting in a better mechanical property of NBR/(PU-sericites)composites.(4)Study on the damping properties of nitrile-butadiene rubber reinforced by graphene derivativeGraphene oxide(GO)was prepared by modified Hammer’s method by using graphite,then the graphene oxide was modified with silane coupling agent(MGO),Nitrile-butadiene rubber(NBR)/GO(MGO)composites and Nitrile-butadiene rubber(NBR)/2,2’-methylenebis(6-tert-butyl-4-methyl-phenol)(AO-2246)/GO(MGO)composites were prepared by two-roll mill mixing method,Fourier Transform Infrared Spectrometer(FT-IR)、Atomic Force Microscope(AFM)、Scanning Electron Microscope(SEM)was used to observe and study the molecular structure and morphology of GO、MGO and composites,and Dynamic Mechanical Analyzer(DMA)was used to study the damping properties of the composites.The result showed that the composites reinforced by GO and MGO had a better damping and mechanical property,the damping property of NBR/GO composites decreased while the damping property of NBR/AO-2246/GO composites increased with the increase of the amount of graphene oxide(GO).The damping property of the composites was increased by the addition of MGO.The reason of the excellent properties of the graphene derivatives was mainly due to its structural characteristics and the associated hydrogen bonds in the structure.But in hindered phenol hybrid system,the speed of increasing of the damping peak decreased with the increase of hydrogen bonds in the structure.The hydrogen bond is not simply a superposition of the damping property.(5)the studies of parameters of fillers on the dynamic mechanical properties Influences of content of fillers on dynamic mechanical properties have been discussed in hybrid damping materials,but the studies of parameters of different fillers on damping performance have not been investigated.In this section of the paper,short fibers and black carbon(CB)were discussed so that it can give a guide to filler choice in hybrid damping materials.The conclusion was as follows:the dynamical mechanical properties of short fibers and CB filling into hybrid damping material was showed difference.Filling CB into hybrid damping material was displayed a better damping capacity than that of short fibers,CB has a Payne effect,there is no Payne effect in GO,the aggregation is an important factor of the flake fillers. |
PDF Full Text Request