杨树浸渍改性材物理及力学性能研究

利用聚乙烯醇缩甲醛复合改性剂对杨树木材进行浸渍改性处理,对比研究了杨树素材与改性材的物理性能及主要力学性能的变化,并利用扫描电子显微镜(SEM)分析了改性剂在改性材中的分布情况。结果表明:改性材的气干密度和抗缩系数(PASE)随改性剂浓度的上升而增加,改性材的气干密度最高为0.41 g/cm3,比素材的提高了13.9%,抗缩系数(PASE)最大提高到47.8%。改性材吸水率随改性剂浓度的上升而下降,与素材相比最大下降了19.2%。当改性剂的浓度为25%时,改性材的弹性模量和静曲强度达最大,分别为27.4%和13%。SEM分析显示改性剂填充于部分木射线以及交错纤维间的空隙中。     

杨树浸渍改性处理材尺寸稳定性研究

利用聚乙烯醇缩甲醛改性剂对杨树木材进行浸渍改性,对其改性材的尺寸稳定性进行研究。结果表明:改性材的径向、弦向和体积干缩率与素材相比均有不同程度的下降;从全干到吸水饱和状态的过程中,当改性剂达到一定浓度时,改性材的径向、体积湿胀率与素材相比有明显下降,弦向线湿胀率下降不明显。从气干到吸水饱和状态的过程中,改性材的径向、弦向湿胀率与素材相比均有不同程度的下降;改性材体积湿胀率随着改性剂浓度的上升而呈下降趋势,当改性剂浓度为30%时,改性材体积湿胀率为6.85%,与素材相比下降了5.54%。改性材吸水率随改性剂浓度的上升而下降,最低可达159%;改性材的抗干缩系数(ASE)随改性剂浓度上升而增加,最大可达47.8%。改性材的尺寸稳定性能要明显优于杨树素材。     

杉木浸渍改性材的尺寸稳定性研究

利用聚乙烯醇缩甲醛改性剂对杉木木材进行浸溃改性，对其改性材的尺寸稳定性进行研究。结果表明：改性材的弦向、径向和体积干缩率与素材相比均有不同程度的下降；改性材的弦向、径向和体积湿胀率与素材相比也均有不同程度的下降，但当改性剂浓度超过20％时，下降才较明显；改性材吸水率随改性剂浓度的上升而下降，最大可由改性前的197％下降到改性后的155％；改性材的抗干缩系数（ASE）随改性剂浓度上升而增加，最大可达18．8％。杉木改性材的尺寸稳定性能要明显优于素材。     

辊压处理大青杨木材的密度和干缩系数变异

对大青杨辊压处理材(压缩率10%～50% )的密度和干缩系数进行测试和研究.结果表明,与素材相比,辊压处理材的全干、气干和基本密度均有所增加,密度变化率＜5%,其中气干密度增幅最大,密度变异与压缩方向无明显相关;气干和全干干缩系数随压缩率增大而变大,变动范围-3.448%～23.678%;弦向干缩系数变化大于径向.     

二羟甲基二羟乙基乙烯脲树脂处理对尾巨桉木材尺寸稳定性的影响

为提升人工林速生材的尺寸稳定性,以人工林尾巨桉（Eucalyptus urophylla×E. grandis）木材为研究对象,采用二羟甲基二羟乙基乙烯脲（DMDHEU）树脂进行真空-加压浸渍处理,分析树脂浓度和加压压力对木材增重率、密度的影响及增重率对木材尺寸稳定性的影响。结果表明,树脂浓度为30%、加压压力为1.2 MPa时,处理材增重率最大（23.85%）;各密度均最高,其中基本密度比未处理材高出26.9%,气干密度高出19.9%,全干密度高出19.8%;气干抗缩率、全干抗缩率、抗胀率和抗吸水率均最大,分别为72.9%、46.6%、53.5%和65.5%。木材增重率和密度均随树脂浓度和加压压力的增加而增加。树脂浓度高于20%、加压压力≥0.9 MPa时,木材增重率和密度增速均减缓。树脂浓度对木材增重率和密度的影响高于加压压力。树脂浓度相同、加压压力≥0.9 MPa时,木材增重率基本保持不变。相同压力下,处理材的尺寸稳定性随增重率增加而增加;压力≥0.9 MPa时,增重率达到9%～10%左右,木材抗胀（缩）率增速减缓。增重率相近、加压压力增加时,木材抗胀（缩）率有所增加,木材抗吸水...     

糠醇浸渍速生人工林木材的干燥特性研究

木材浸渍改性商业应用的主要技术难点之一是二次干燥速度慢、易开裂、易变形。本文以杨木和杉木为研究对象,使用浓度为30%和50%的糠醇水溶液对其进行浸渍改性,再以百度干燥法分析糠醇浸渍材的干燥特性,辅以干缩试验和剖面密度(VDP)试验探究干燥缺陷成因。结果表明：50%浓度浸渍材的干燥缺陷等级均大于30%浓度浸渍材,杨木浸渍材的等级均高于杉木浸渍材;杉木30%和50%浓度浸渍材百度干燥平均时间分别为24 h和29 h,而杨木30%和50%浓度浸渍材分别为20 h和30 h。浸渍材不同位置的干缩系数存在显著差异,浸渍后密度分布更加不均匀。杉木和杨木糠醇浸渍材二次干燥困难的主要原因为固化的糠醇堵塞了水分内部迁移通道,从而使干燥速度降低;糠醇分布不均匀导致干缩系数差异进一步加大,处理材易开裂、易变形。     

水性乙烯基单体接枝共聚改善杨木性能的研究

为探究环保的木材改性方法,以水溶性乙烯基单体甲基丙烯酸-2-羟乙酯(HEMA)和N-羟甲基丙烯酰胺(NMA)为改性剂,处理速生杨木,并考察改性剂配比、浓度对改性材性能的影响。结果表明,改性剂HEMA与NMA的质量比为80∶20、浓度40%时,改性材增重率为40.46%,抗体积膨胀率为60.77%,抗弯强度和弹性模量分别提高20.19%和38%;且同样的改性效果时,该改性剂相比传统改性处理所需的处理温度低、用量少。     

美杨与新生杨木材物理力学性质研究

通过对新生杨和美杨物理力学性质的测定分析,结果表明,美杨的气干密度为0.399g/cm~3,基本密度为0.347g/cm~3,径向干缩系数为0.183%,弦向干缩系数为0.312%,抗弯弹性模量为7 373.34Mpa,抗弯强度为57.11MPa,顺纹抗压强度为18.36MPa。新生杨的气干密度为0.365g/cm~3,基本密度为0.330g/cm~3,径向干缩系数为0.188%,弦向干缩系数为0.240%,抗弯弹性模量为6 733.68MPa,抗弯强度为51.53MPa,顺纹抗压强度为16.48MPa。综合分析各项指标,美杨的材性优于新生杨的材性。     

二氧化硅改性处理桉树生材的材性分析

采用溶胶-凝胶法,对含水率142％～146％的速生桉树生材进行改性处理,采用电镜SEM、X-射线能谱仪DAX及红外光谱FTIR分析,观察木材微观结构和SiQ分布状态,并检测理化性能.结果表明:浸渍时间不同,改性材中的SiO2含量和分布不同;改性材的增重率最大达45％,气干密度可提高至0.6 g/cm3左右,抗弯强度、硬度及耐光老化性能等均相应提高.     

改性三聚氰胺脲醛树脂增强人工林杉木的性能

采用改性三聚氰胺脲醛(MUF)树脂和递进式逐级渗透处理工艺,对人工林杉木进行浸渍处理,制备增强改性杉木木材,并与未改性素材进行物理化学性能的对比分析。结果表明:改性材的绝干密度、抗弯强度和抗弯弹性模量均有所提高,吸水率降低,热稳定性提高;FTIR和SEM分析显示,改性剂被成功引入、填充,并固化于木材管胞和纹孔等孔隙中。     

PF树脂浸渍速生杉木的性能研究

速生杉木通过浸渍PF树脂并压缩改性后,力学性能得到大幅度提高,且随着树脂浓度和压缩率的增加而提高。增重率与真空度、浸渍压力、时间有关,并随着其增加而增大;抗胀(缩)率和阻湿率与树脂的浓度有关,当树脂浓度从0上升到10%时,ASE和MEE的值变化较大,当树脂浓度超过10%后趋于平缓;在树脂浓度相同的情况下,较大压缩的恢复率也相应较大,当树脂浓度低于10%时,随着浓度增加,恢复率急剧下降,浓度达到15%以上时,恢复率几乎没有变化。     

酚醛树脂处理杨木、杉木尺寸稳定性分析

采用酚醛树脂浸渍处理人工林杨木、杉木,然后通过热压定型工艺制得表面密实化木材。对其尺寸稳定性的分析结果表明:处理试材的增重率、抗胀率和阻湿率随树脂浓度的增加而成比例增大,弦向和径向干缩率明显降低,在树脂浓度较低时变化较大,当达到一定量时变化趋于稳定。就压缩变形恢复率而言,当树脂浓度超过10%,压缩变形恢复率很小,说明表面密实化木材的压缩变形几乎被固定。     

Creep of Chinese fir wood treated by different reagents

In order to investigate the effect of different reagents on changes of the crystalline region and amorphous region (Matrix) in wood cell walls, the creep behavior of Chinese fir (Cunninghamia lanceolata) wood treated with dimethyl sulfoxide(DMSO) and diethyl amine, sulfur dioxide and dimethyl sulfoxide mixture (1)EA-SO2-DMSO), and the untreated wood at oven-dried, air-dry and water-saturated states during adsorption and desorption processes were all examined in air or in water. The measurements were carded out at ambient temperature and atmospheric pressure. The load is constant with 62 g or 0.607 6 N. The results obtained were as follows: 1) The instantaneous compliance J0 and the creep compliance J of specimens decrystallized with DEA-SO2-DMSO solution were bigger than those of DMSO swollen wood, and the latter was still much bigger than those of untreated wood. 2) For untreated wood, J0 and J increased with equilibrium moisture content (EMC) of wood, but there was not apparent correlation between wood EMC and the relative compliance. 3) Specimens treated with DMSO and DEA-SO2-DMSO mixture were recrystallized after immersion in water, and the degree ofrecrystallization of the former was larger. 4) For oven-dried specimens, the creep compliances in water were bigger than those in air. But for fiber-saturated and water-saturated specimens they were nearly equivalent to each other.     

Pilot Study to Examine Radial Variation in Annual Ring Width, Density and Shrinkage

The annual ring width, density and shrinkage variation from pith to bark in Chinese fir (Cunninghamia lanceolata) and Boka sugi (Cryptomeria japonicd) were studied and compared. The results show that the ring width decreased sharply from pith to bark for Chinese fir. However, the ring width variation pattern for Boka sugi followed a different way, i.e., the ring width decreased to the fifth ring, increased to the tenth ring, decreased again to the fifteenth, and then increased to the twentieth, where it became constant. The large variations of Boka sugi appeared to show the maintenance of fast growth for many years. The annual ring mean density of Chinese fir increased gradually from pith to bark. However, the density changes for Boka sugi indicated the opposite trend, i.e., the mean density decreased gradually from pith to bark. The former showed a pattern as the same as a pine and a larch, and the latter was often found in a cedar and a cypress. The longitudinal shrinkage in juvenile wood was much hig     

杉木积成材制造工艺研究

研究以杉木制材板皮为原料，采用梳解加工法制造杉木积成材的制板工艺。结果表明，密度为0．6g／cm^3，厚为16mm的杉木积成材，其较佳制造工艺为木束条含水率6％-9％，施胶量8％-9％，热压压力2．0MPa，热压温度160℃。热压时间10min。     

阻燃剂WFRJ1改性木材的体积稳定性和涂饰性能

用阻燃剂ＷＦＲＪ１处理大青杨木材并对处理材的阻燃性能、涂饰性能和体积稳定性进行测定。结果表明：ＷＦＲＪ１可用于木制品的阻燃处理。当ＷＦＲＪ１浓度为１０％时,氧指数可达到５０％以上,与水溶性ＲＦ树脂复配,可大幅度提高处理材的抗胀缩率和阻湿率,增加体积稳定性。经ＷＦＲＪ１处理后杨木单板的涂饰性能未受影响。     

Factors affecting the resinification of liquefied phenolated wood

Wood of Chinese fir and poplar were liquefied in phenol at 150℃ and atmospheric pressure. The liquefied wood were reacted with formaldehyde to synthesize the liquefied wood-based resin. The factors affecting the resinification and the properties of new resin were investigated. The results show that the formaldehyde/liquefied wood molar ratio, reaction temperature, reaction time and sodium hydroxide/liquefied wood molar ratio have important influence on the resin characteristics. With the increase of formaldehyde/liquefied wood molar ratio, the yield of resin increases, and the flee phenol content of resins decreases, showing that the resinification of liquefied wood is more complete at higher formaldehyde/liquefied wood molar ratios. The reaction temperature on the viscosity of the liquefied resin has considerable effect; the viscosity of resin increased with increasing reaction temperature, and the amount of liquefied poplar resin increased more quickly than that of liquefied Chinese fir resin. The resinification time also has obvious influence on the viscosity of resin; the viscosity of liquefied poplar resin is more sensitive to resinification time compared with that of liquefied Chinese fir. The amount of sodium hydroxide can improve the water miscibility of liquefied wood resin. The optimum sodium hydroxide/liquefied wood molar ratio for preparation of liquefied wood-based resins exceeds 0.4.