Improvement Of Acoustic Vibration Performance Of Wood By There Treatments

In order to achieve value-added application of poor wood and efficient utilization of wood for instrument soundboard production and thereby alleviating the imbalance between supply and demand,in this research,Paulownia Sieb.et Zucc.wood are chosen as the main research object for instrument production.cold water,hot water and phenethyl alcohol extraction treatment,Furfuryl alcohol impregnation,PVA impregnation are chosen as three chemical treatment methods to improve the vibration properties of test wood materials.The main research contents and conclusions are as follows:(1)The acoustic vibration performance of P.elongata wood is improved after dealing with the cold water,hot water and phenethyl alcohol extraction.But the cold water extraction treatment is best.After cold water extraction treatment,P.elongata wood density reduced 2.29%,the extraction of substance content in total of wood 12.3%.Than the dynamic modulus of elasticity E/?and R value were 23.75GPa and 20.46m~4/Kg?s,increased by 2.11%and 3.43%respectively.?and?was reduced by 1.26%and 4.21%respectively,the values were respective 1.15Pa?s/m and-0.048.E/G value increased by 4.31%.The value is 17.49?(2)The furfurylated wood has relatively high dimensional stability.From the point of acoustic vibration efficiency evaluation indicators,acoustic impedance?and attenuation coefficient?are effectively improved.From the aspect of vibration sound indicator E/G,the furfuryl alcohol modification can significantly improves the sound quality of Paulownia,when the concentration is25%and curing time is 8h.And under other process conditions,it reduces the sound quality of Paulownia.But furfuryl alcohol modification has a negative impact on the specific dynamic elastic modulus E/?and acoustic radiation damping R.In general,the best treatment for concentration 25%,curing temperature 8h.This process condition,the Paulownia.wood of various acoustic vibration parameters are as follows:acoustic impedance?,attenuation coefficient?,the two indicators increased by 21.1%?156%,the value was respective 3.784Pa?s/m?-0.053.And the E/G index increased by 38.8%.It is 17.9.Than the specific dynamic elastic modulus E/?is 14.51GPa and acoustic radiation damping R is 8.113m~4/Kg?s,the two indicators were reduced by 36%and 45%respectively.(3)Compared with furfuryled wood,the acoustic performance of P.elongata wood which was impregnated was better.Specific performance is as follows:after PVA impregnation treatment,dimensional stability was improved significantly;P.elongata wood acoustic attenuation coefficient?and E/G was improved,the effect is very obvious.But only a modest improvement of?;At the same time,E/?and R appeared weak decrease.Comprehensive consideration in equipment whose dynamic modulus of elasticity and acoustic radiation quality constant value is higher,acoustic impedance,attenuation coefficient value is low.Choose PVA liquid concentration was 25%,the curing time of12h,acoustic modification effect is best.The P.elongata wood dimensional stability increased by12.9%,?,?and E/G improved by 0.82%,25.7%and 16.7%and the values were 4.633Pa?s/m?-0.03?14.81respectively.E/?and R was reduced by 1.69%and 1.09%,the value were 21.54GPa?17.71m~4/Kg?s respectively.(4)The overall test results show that,cold water extraction treatment can effectively improve acoustic vibration properties of wood;When choose the suitable technological conditions,polyvinyl alcohol impregnation can improve the performance of acoustic vibrations on the wood effectively;But furfuryl alcohol impregnation can improve acoustic impedance?and attenuation coefficient?,but it has a negative effect on the specific dynamic elastic modulus E/?and acoustic radiation damping R.Through comprehensive comparison,the order of the vibration performance improvement of P.elongata wood is that,the cold water extraction process>polyvinyl alcoho impregnation treatment>furfuryl alcohol impregnation treatment.Furfuryl alcohol modified wood is a complex chemical reaction,if on the basis of the modification,the catalyst,reaction temperature,time and so on can be to further research,and how to introduce new chemicals to improve the weaken acoustic vibration parameters.Furfuryl alcohol is also a very good acoustics modified reagents effectively.