不同厚度针、阔叶材吸湿特性研究  

Study on hygroscopic properties of softwood and hardwood with different thicknesses

作　　者：刘畅 曹帅 李明晗 周楠 蔡家斌 LIU Chang;CAO Shuai;LI Minghan;ZHOU Nan;CAI Jiabin(College of Materials Science and Engineering,Nanjing Forestry University,Nanjing 210037;Fuyang Jinmu Arts and Crafts Co.Ltd.,Fuyang 236000)

机构地区：[1]南京林业大学材料科学与工程学院,南京210037 [2]阜阳市金木工艺品有限公司,阜阳236000

出　　处：《安徽农业大学学报》2023年第1期36-43,共8页Journal of Anhui Agricultural University

基　　金：江苏省科技项目(SZ-SQ2019023)资助。

摘　　要：为了研究不同厚度针、阔叶材吸湿性之间的差异,通过静态饱和盐溶液法进行等温吸湿试验,再用Hailwood-Horrobin(H-H)模型拟合等温吸湿曲线,分析3个树种4种厚度试样的平衡含水率(EMC,equilibrium moisture content)、吸湿速率、单层分子吸附水和多层分子吸附水的差异。结果表明,在97%相对湿度(RH,relative humidity)下,1、4和8 mm厚度试样达到最终平衡时的平衡含水率分别为云杉20.54%、22.76%和22.75%,美洲黑杨19.15%、21.74%和22.26%,橡木20.94%、21.90%和22.95%,终了平衡含水率随厚度增大而增大。当厚度达到20 mm时,试样终了平衡含水率均低于厚度较小试样,说明吸湿滞后对厚板影响增大。薄试样吸湿速率大于厚试样,因为水分子容易渗入薄板内部。3个树种间终了平衡含水率也存在差异,如1 mm厚度橡木试样的平衡含水率(20.94%)>云杉(20.54%)>美洲黑杨(19.15%),这与橡木密度大、结晶度低以及单层吸附点位多有关。3个树种间云杉吸湿速率最快,因为其密度最小,水分子能迅速通过大毛细管进入木材内部。H-H模型拟合显示在低相对湿度下木材以单层水分子吸附为主,高相对湿度以多层吸附为主,H-H模型拟合优度R^(2)均大于0.99,能较好地拟合这3个树种的等温吸湿过程。In order to study the difference of hygroscopic properties between softwood and hardwood with different thickness,sorption experiments were carried out by static saturated salt solution method,the sorption isotherm was fitted by Hailwood-Horrobin(H-H) model,and the differences in equilibrium moisture content(EMC),adsorption rate,monolayer and polylayer molecular adsorption water were analyzed for samples of three tree species in four thicknesses.The results showed that at 97% relative humidity(RH),the equilibrium moisture contents of 1,4 and 8 mm thicknesses were 20.54%,22.76% and 22.75% for spruce,19.15%,21.74% and 22.26%for Populus deltoids,and 20.94%,21.90%,22.95% for oak,and the final equilibrium moisture content increased with the increase of thickness.When the thickness reached 20 mm,the final equilibrium moisture content in the sample was lower than that in the sample with smaller thickness,indicating that the influence of hygroscopic hysteresis on the increase of the thick plate.The adsorption rate of the thin sample was higher than that of the thick sample because that the water molecules were easily penetrated into the thin plate.There were also differences in hygroscopic equilibrium moisture content among the three species.For example,the equilibrium moisture content of oak sample with 1 mm thickness(20.94%) > spruce(20.54%) > Populus deltoids(19.15%),which was related to the high density of oak,low crystallinity and multiple adsorption sites of monolayer.Among the three species,spruce had the fastest adsorption rate,because its density was the lowest,and water molecules could enter the wood rapidly through the large capillary.H-H model fitting showed that wood was mainly adsorbed by monolayer water molecules at low relative humidity,and multilayer adsorption at high relative humidity.The R~2 of H-H model was greater than 0.99,which could better fit the isothermal hygroscopic process of these three tree species.

关 键 词：针叶材 阔叶材 试样厚度 吸湿特性 H-H模型 

分 类 号：S781.62[农业科学—木材科学与技术]