Study On Structure And Acoustic Properties Of Eucommia Ulmoides/Chlorinated Butyl Rubber Nanocomposites

With the increasing concern of marine noise pollution and the continuous development of underwater detection equipment,underwater acoustic materials are facing new challenges,and higher requirements in broadband,pressure resistance,low frequency and other aspects are put forward.Chlorinated butyl rubber(CIIR)has a high loss factor and a wide damping temperature range(-60～10),which is widely used in the field of damping and sound absorption.But its low modulus makes it difficult to maintain shape and acoustic performance under high pressure.Eucommia ulmoides gum is a unique bio-based rubber in China.It is an isomer of natural rubber,and its molecular chain is easily arranged and crystallized.It has the characteristics of high modulus and crystallization melt damping mechanism,and has a good application prospect in tires,medical materials and underwater acoustics.This topic mainly carries on three parts research.The first part is the study of intrinsic acoustic properties of chlorinated butyl rubber.This part mainly explored the change of modulus and loss factor of chlorinated butyl rubber from crosslinking density and packing system,as well as the influence on sound reflection,sound absorption and sound transmission.Crosslinking density was an atmospheric pressure method to control rubber properties.With the increase of crosslinking density,the storage modulus of chlorinated butyl rubber increased,the maximum loss peak decreased and moved to high temperature,but the overall effect was not significant.With the increase of crosslinking density,sound absorption decreased gradually,but it had little influence on sound reflection and sound transmission.Based on the selection of low crosslinking density chlorinated butyl rubber,the influence of different fillers on its acoustic properties was studied.The average sound absorption coefficient of chlorinated butyl rubber in 3～31k Hz could be increased by filling zinc oxide and hollow glass beads.The addition of carbon black and graphite could reduce the acoustic reflection property and sound absorption performance of the chlorinated butyl rubber,and greatly improved the sound permeability of the chlorinated butyl rubber,the average sound permeability coefficient was above 0.91.The second part is the study of phase structure and acoustic properties of eucommia ulmoides/butyl chloride blends.The phase states of eucommia ulmoides gum and chlorinated butyl rubber were investigated by atomic force microscope.When a small amount(10-30parts)of eucommia ulmoides gum was added,the sound absorption performance of chlorinated butyl rubber was improved.When 30 parts of Eucommia ulmoides gum was added,the sound absorption performance was the best,and the average sound absorption coefficient was 0.7 under atmospheric pressure,but decreased significantly with the increase of pressure.With the increase of the number of eucommia ulmoides gum components,the dispersed phase of eucommia ulmoides gum gradually reunited to form a strip continuous phase.The modulus of the mixture increased,the loss factor decreased,the sound absorption performance decreased,the acoustic performance and sound transmission improved,and the acoustic performance was reduced by pressure,and the pressure resistance was improved.In the third part,zinc oxide filler was added on the basis of eucommia ulmoides gum/chlorinated butyl adhesive,and eucommia ulmoides gum hard frame structure was introduced to embed the chlorinated butyl composite material to improve the pressure resistance of the composite material.The mechanical properties,dynamic thermomechanical properties and acoustic properties of zinc oxide/eucommia ulmoides/chlorinated butyl rubber composites were studied.It was found that when the number of eucommia ulmoides was 40～60phr,the composites showed good pressure resistance and sound absorption performance.When the blending ratio was 40/60,it remained good under normal pressure,the average sound absorption coefficient was 0.69,and the average sound absorption coefficient of 3MPa was 0.41.The average sound absorption coefficient under high pressure was nearly twice that of pure eucommia ulmoides gum/butyl chloride blend,showing good pressure resistance and sound absorption effect.