微波处理对辐射松吸声性能的影响  

Effect of Microwave Treatment on the Sound Absorption Performance of Radiata Pine

作　　者：樊正强 彭立民[1,2] 刘美宏[1] 冯云 Fan Zhengqiang;Peng Limin;Liu Meihong;Feng Yun(Research Institute of Wood Industry,CAF,Beijing 100091;Research Institute of Forestry New Technology,CAF,Beijing 100091)

机构地区：[1]中国林业科学研究院木材工业研究所,北京100091 [2]中国林业科学研究院林业新技术研究所,北京100091

出　　处：《林业科学》2021年第7期142-149,共8页Scientia Silvae Sinicae

基　　金：中央级公益性科研院所基本科研业务费专项资金项目“木结构房屋墙板隔声性能的研究”(CAFYBB2019SY041)。

摘　　要：【目的】采用高强度微波对辐射松进行改性处理,探究不同微波功率、处理时间和木材纹理方向对辐射松吸声性能的影响,以提高木材的附加价值、拓展木材的应用领域。【方法】将新采伐的辐射松生材干燥至含水率40%~60%,在不同微波功率(100、120和140 kW)与处理时间(20和30 s)组合条件下处理辐射松木方,获得微波处理材。采用传递函数法测量微波处理材径切面和弦切面的法向吸声系数,探讨不同处理条件下辐射松吸声性能的变化规律,借助光学显微镜和扫描电子显微镜观察辐射松的解剖构造和微波处理前后的微观结构形貌。【结果】微波处理材与对照材相比,密度和含水率显著下降,不同处理条件下辐射松吸声性能均有不同程度提升,吸声系数提高4.79%~201.9%,平均吸声系数最高达0.320;不同条件下微波处理材的吸声系数在1000 Hz以下的低频范围内变化不显著,吸声系数呈先上升后下降的趋势,在1000 Hz左右出现吸声低谷,在1000 Hz以上差异显著,吸声系数随频率升高呈上升趋势;微波功率越大、处理时间越长,处理材吸声性能越好,吸声系数曲线上升趋势越大;处理材弦切面的吸声系数比径切面高9.6%~29.6%,对照材径切面的吸声系数在1000 Hz以上低于对照材弦切面,在1000 Hz以下高于对照材弦切面;辐射松弦切面相较于径切面存在丰富的单列木射线和少量纺锤形木射线,微波处理材轴向管胞壁和胞间层出现裂缝,管胞上纹孔膜消失,木材孔隙率和相邻孔隙之间的连通性增加,声波在木材内部传播可更大概率地与孔隙壁摩擦,增加声能损耗从而达到更好的吸声效果;微波功率、处理时间和木材纹理方向与吸声系数的相关性分别为0.519、0.637和0.705,3个变量对吸声系数均有中等程度影响,其中木材纹理方向对吸声性能的影响最大。【结论】辐射松未处理材弦切面和径切面的平均吸声系【Objective】Because of the poor sound absorption performance of radiata pine(Pinus radiata),microwave modification was used to improve the sound absorption performance of radiata pine.The influences of different microwave power,treated time and wood grain directions on the sound absorption performance of radiata pine were explored so as to improve the added value of wood and to expand the application field of wood.【Method】First of all,the microwave treated wood was obtained by drying the moisture content of radiata pine green wood to 40%-60%in different microwave powers(100 kW,120 kW and 140 kW)and different treated times(20 s and 30 s).Transfer function method was used to measure the sound absorption coefficient(SAC)of microwave treated wood on their radial section and tangential section,in order to discuss the changing rules of the sound absorption performance of radiata pine in varying treated parameters.Optical microscope and scanning electron microscope(SEM)were used to observe the anatomical structure and microwave treated wood microstructure morphology,respectively.【Result】Compared with the control samples,the density and moisture content of radiata pine decreased significantly after microwave treatment.The sound absorption performance of radiata pine was improved to different degrees in different microwave treated parameters.The SAC increased about 4.79%-201.9%,and the best average SAC was up to 0.320.The SAC of microwave treated wood under different parameters did not change significantly in the low frequency range below 1000 Hz.The sound absorption curve showed a trend of first rising and then falling,and the sound absorption trough appeared around 1000 Hz.The difference of SAC was significant above 1000 Hz,and the curve of SAC showed an upward trend.The higher the microwave power and the longer the treated time,the better the sound absorption performance of the microwave treated wood,and the higher the trend of the sound absorption coefficient curves.Compared with the radial section sample,t

关 键 词：辐射松 微波处理 吸声 

分 类 号：S781.38[农业科学—木材科学与技术]