Preparation And Properties Of High Temperature Resistant Damping Materials

The damping materials have been developed rapidly at present and found their wide applications in various fields.However,the commonly used damping materials are unable to meet all the requirements for the collective properties of high-temperature damping resistance,the large loss factor and excellent heat resistance.Epoxy resins with great amount of functional groups have excellent heat resistance,which can be used in the harsh working conditions at extremely high temperatures.But,the materials have the disadvantages of brittleness and poor damping effect.In this paper,high temperature resistant epoxy resin(BH140),curing agent(MT305),benzyl glycidyl ether(modifier 692),butyl diglycidyl ether(modifier 622),damping agent UN513(modifler 513)and organic nano montmorillonite(OMMT)were used as the main raw materials to prepare a series of epoxy resins.The effects of the dosage of curing agent,the type and dosage of modifier,and the dosage of organic nano montmorillonite on the heat resistance and damping properties of the obtained epoxy resins were investigated through characterization of the mechanical properties,crosslinking density,heat resistance and damping properties of the cured epoxy resin.The epoxy resins with high-temperature damping property were obtained.The conclusions are as follows:(1)The molecular structure of a cured epoxy resin with excellent heat resistance was designed,and the cured epoxy resin was prepared by using epoxy resin BH140 and curing agent MT305.By adjusting the molar ratio of the resin and curing agent,the ratio of the cured resin with the best heat resistance was determined as such that the molar ratio of BH140 to MT305 was 1:3,the corresponding cured epoxy resin had the best comprehensive properties,including the glass transition temperature of 225.3 □,the initial decomposition temperature(T5%)of 354.3 □,the maximum damping factor of 0.5095,and the damping temperature range of 181.7 to 257.2 □.(2)The damping properties of the cured resin can be improved by changing its crosslinking structure through introduction of side chains into the crosslinking site.The addition of benzyl glycidyl ether(692 modifier)could improve the damping properties of epoxy resin.When the amount of 692 modifier was 10%,the corresponding cured epoxy resin had the best comprehensive properties,including the glass transition temperature of 174.3□,the thermal decomposition temperature(T5%)of 358.2□,the maximum damping factor of 0.6355,and damping temperature range of 156.8-225.1 □.(3)Organic nano-montmorillonite(OMMT)has a special layered structure.Under high temperature,OMMT was uniformly dispersed in the material during curing through peeling reaction to prepare the cured resin with peeled OMMT,which had the improved toughness and damping properties.When the amount of organic nano-montmorillonite is 5%,the cured epoxy resin product has the best comprehensive properties,including the tensile strength of 72.1MPa,the impact strength of 48.6 kJ·m-2,the elongation at break of 7.4%,the glass transition temperature of 217.1 □,the thermal decomposition temperature(T5%)of 362.1 □,the maximum damping factor of 0.6537,and the damping temperature range of 165.1-255.2□.