人工林软质木材表面密实化新技术

采用一种新型木材改性处理剂，分别以改性异氰酸酯浓度5％、10％、15％、20％，对美国人工林火炬松（Pinus taeda）进行表面密实化处理。结果表明，随着树脂浓度的增加，无论是冷水浸泡还是煮沸，木材的吸水厚度膨胀率和压缩变形恢复率明显降低。表面密实化后，火炬松处理材的MOR和MOE值分别比素材提高43．9％和30．1％；水浸24h和煮沸2h后的湿状抗弯性能比素材略低，干状抗弯性能明显比素材高，MOR分别高28．0％和25．76％；MOE分别高22．55％和27．79％。改性异氰酸酯浸渍处理后的表面密实化木材，具有一定的阻燃效果；表面耐磨耗性能和表面硬度亦明显改善。     

异氰酸酯树脂固定人工林杨木压缩变形的研究

采用异氰酸酯树脂对人工林杨木进行表面密实化处理,目的是固定杨木的压缩变形,改善木材的材性。结果表明:随着水溶液中树脂质量分数的增加,木材的尺寸稳定性逐渐提高。     

水热控制下杨木的表层密实化及固定技术

通过改变木材的表层水分含量,并利用热压机压板的热量对木材进行水热控制,开展毛白杨木材的表层密实化研究,分析毛白杨木材表层压缩密实化后的密度、硬度和恢复率等能指标。结果表明:表层密实化后的毛白杨木材的表层密度达到0.92g/cm3,为对照材的1.8～2.1倍;硬度达到22.3N/mm2,为对照材的2.4倍;压缩木经180℃、4h的热处理后,变形恢复率可降低30%。     

低分子量酚醛树脂处理人工林杨木表面压密材材色研究

采用不同浓度的水溶性低分子量酚醛树脂对人工林杨木进行浸渍处理,然后热压固化树脂于木材中。木材表面密实化处理后,检测表面颜色变化。结果表明:随着酚醛树脂浓度以及加热时间的增加,浸渍材的表面压材色发生转变。     

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。     

木材压缩变形固定处理技术研究进展

压缩密实化是木材提质增优的处理方法之一。木材作为一种具有形状记忆效应的天然有机高分子材料，当被压缩或弯曲后，在温度和湿度等环境因子的影响下容易发生蠕变回复。木材压缩变形的回复对木材制品的尺寸稳定性和力学性能均有重要的影响，研究木材压缩变形固定处理技术对木材加工改性和高效利用具有重要指导意义。概述了木材压缩变形固定处理技术在国内外的研究进展和现状，重点梳理归纳了水热（蒸汽）预处理、压缩后热处理以及化学处理对木材压缩变形固定的研究进展。在此基础上，分析和提出了木材压缩变形固定处理技术的思路和未来发展方向，以期为压缩材的高效加工利用提供科学指导。     

多元羧酸类化合物对木材大压缩量变形的固定作用

以多元羧酸类化合物为酯化剂、以无机盐类为催化剂的交联体系是一类新型的水溶性、无毒害、无污染、木材交联反应未采用过的非甲醛系试剂交联体系。本文研究了这类非甲醛系试剂对木材大压缩量变形的固定作用,结果表明浓度９％的１,２,３,４丁烷基四羧酸处理大青杨试件,干状态的变形恢复率较低,沸水中变形恢复率接近于２７０１％。用１,２,３,４丁烷基四羧酸交联处理木材可以固定压缩变形,适宜的树脂浓度为９％。材色由偏红向偏黄方向转变。     

高温水蒸汽处理固定大青杨木材横纹压缩变形的研究

采用高温水蒸气处理和加热处理固定大青杨木材压缩变形,测定了木材的抗胀(缩)率(ASE)、阻湿率(MEE)、质量损失率(WL)、压缩率、压缩变形恢复率等各项指标,并对两种处理结果进行比较。结果表明,无论是高温加热处理还是高温水蒸气处理,木材的尺寸稳定性明显得到提高。在相同温度条件下,当ASE的值超过50%时,高温水蒸气处理所需要的时间远远小于高温加热处理所需要的时间;当温度为180℃时,加热处理需要15~20 h,而水蒸气处理仅需要8 min,压缩变形即被固定。     

高温水蒸气处理固定大青杨木材横纹压缩变形的研究

采用高温水蒸气处理和加热处理固定大青杨木材压缩变形，并对两种处理结果进行比较。测定了木材的抗胀（缩）率（ASE）、阻湿率（MEE）、质量损失率（WL）、压缩率、压缩变形恢复率等各项指标。结果表明：无论是高温加热处理还是高温水蒸气处理，木材的尺寸稳定性明显得到提高。在相同温度条件下，当ASE的值超过50％时，高温水蒸气处理所需要的时间远远小于高温加热处理所需要的时间，当温度为180℃时加热处理需要15－20h，而水蒸气处理仅需要8min，压缩变形被固定。     

浸渍及压缩制备密实化木材的研究进展

对人工林木材进行密实化处理是改良木材性能、拓宽应用领域的重要途径之一。本文聚焦木材密实化工艺及其机理,重点阐述浸渍和压缩两种密实化处理方法,分析不同密实化方法对改性木材性能的影响,并展望木材密实化研究的发展趋势。     

竹模板湿变形特性的初步研究

本文研究了在使用竹模板浇成的混凝土结构产生严重变形的原因，是由于竹模板吸收了现浇混凝土的水分所造成。进一步测定了竹模板的相对吸水率对其静曲强度和弹性模量的显著影响，并给出了计算公式，供在竹模板的间距支撑设计和使用时参考。     

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。     

木材浸渍用低分子量低色度酚醛树脂

为了探讨低分子量酚醛树脂处理木材导致材色加深的因素，采用紫外（ＵＶ）和红外（ＵＶ）吸收光谱分析低分子量酚醛树脂在合成和固化过程中主要产物的光吸收作用，确定了采用低分子量酚醛树脂改性木材化学药剂的合理配制和处理条件，并测定了处理后大青杨木材材色。结果表明：低分子量酚醛树脂生木材材色的色差变化较小，长时间放置材色稳定。     

Compressive deformation of phenol formaldehyde (PF) resin-impregnated wood related to the molecular weight of resin

The effects of molecular weight of PF resin on the deformation behaviour of NaClO₂ treated resin-impregnated wood during compression were investigated. Blocks of Japanese cedar were subjected to 2% NaClO₂ aqueous solution. This was repeated up to four times resulting in a weight loss of 28%. Treated and untreated samples were impregnated with PF resin having different molecular weight. With increasing molecular weight, weight gain and volume gain decreased for untreated PF resin-impregnated wood, while NaClO₂ treated wood impregnated with high molecular weight PF resin showed almost double the weight gain compared to untreated condition. NaClO₂ treatment has shown considerable potential for high compression of PF resin-impregnated wood at lower pressing pressure regardless of the molecular weight of the resin. Low to high molecular weight resin was shown to penetrate into NaClO₂ treated wood as estimated by weight gain contributing to the plasticization of cell wall considerably and thus resulting in cell wall collapse at low pressing pressure. The density of NaClO₂ treated wood impregnated with high molecular weight resin attained a value of over 0.8 g/cm³ which is close to the density of untreated wood impregnated with low molecular weight resin. Such compressed wood exhibited high dimensional stability after boiling for 3 h. Thus, the penetration of resin into wood contributes to highly compressed dimensional stable resin-impregnated wood at low pressing pressure.     

Adhesive performance of woods treated with alternative preservatives

The extended use of woods treated with traditional or alternative preservatives for exterior applications requires an assessment of wood adhesive performance. This study attempts to evaluate the performance of wood adhesives for woods treated with various waterborne preservatives. Two softwood species, i.e. Korean pine (Pinus koraiensis Sieb. et Zucc.) and Japanese Larch (Larix leptolepis [Sieb. et Zucc.] Gordon) were treated with copper–chrome–arsenic (CCA), CB-HDO, or copper azole (CY), and then bonded with four different wood adhesives such as urea–melamine–formaldehyde (UMF) resin, melamine–formaldehyde (MF) resin, phenol–formaldehyde (PF) resin, and resorcinol–formaldehyde (RF) resin. The performance of these adhesives was evaluated by measuring the dry shear strength of adhesive-bonded wood block on compression. Both UMF and MF resins produced a relatively strong adhesive strength for CY-treated pine and larch woods. The PF resin also produced good bond strength when bonded with either larch wood treated with CY or pinewood treated with CB-HDO. The best result was obtained when the CB-HDO-treated woods were bonded with RF resin. For a better bond strength development, a proper combination of adhesive, preservative, and wood species should be selected by taking into consideration of the characteristics of these three parameters as well as their interactions.     

化学改性大青杨木材的阻燃性能研究

以树脂型阻燃剂与低分子酚醛树脂复配作为药剂对大青杨进行改性处理,提高木材的阻燃性。研究表明,当阻燃剂浓度为10％时,其氧指数为51％;当浓度为25％时,氧指数可达到61％;对其进行红外分析,发现存在C=N键吸收峰;热重分析结果,其吸热量明显变小。     

软质木材的表面密实化

探讨软质木材表面密实化的理想状态和途径,研究用酚醛树脂浸渍、再进行不同程度压缩木材的表面密实化效果.试验结果表明,浸渍压缩后木材密度从表层到内层的分布呈现一定的梯度,表面密度均高于内层密度和平均密度;试件的表面硬度、耐磨性和尺寸稳定性均有不同程度的提高.     

CHEMICAL AND PHYSICAL CHANGES OF STEAM TREATED WOOD CHIP

High dimensional stable particlcboards could be produced by usisng saturatedsteam treated wood chip at elevated pressures.Sample Particleboards were made from woodchip of Birch(Platyphylla).The component changes of steam treated wood chip were analysedby infrared.Infrared spectra demonstrated that the hemicelluloses in steam treated chip wereless than those in untreated chip.This is one of the main reasons why steam treatment could im-prove particlcboard stability.The free radical concentration of steam treated chip surfaces wasanalysed by ESR spectroscopy.The results showed that free radical concentration of treatedchip surface was higher than that of untreated chip surface.The glueyness of chip increased andparticlcboard resin content decreased.     

用低分子树脂进行泡桐木材表面强化的研究

合成一种低分子三聚氰胺－甲醛树脂．对泡桐木材表面进行强化，测试改性后木材的硬度、耐磨性、抗胀缩率、容胀率及增重率等技术性能指标。经过分析，得出泡桐木材可用横向压密，化学试剂固定变形的方法，提高木材的有关物理性能参数的结论。