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采用高频真空干燥、常规窑干和高温干燥3种方法对杉木人工林木材的心、边板材进行干燥处理,用毛细管上升法评价干燥后试样的浸注性能,用半薄切片法测定干燥试样具缘纹孔的闭塞率,最后用扫描电子显微镜观察干燥试样微观构造的变化,比较分析3种干燥方法对杉木人工林木材浸注性的影响机理.结果表明:对于杉木边材,经高频真空干燥后试样的浸注性显著高于常规干燥和高温干燥后试样的浸注性,后2种干燥方法对试样浸注性影响的差异并不显著;对于杉木心材,高频真空干燥与高温干燥后试样的浸注性存在显著差异,而高频真空干燥与常规干燥之间、高温干燥与常规干燥之间对试样浸注性的影响差异均不显著;3种干燥方法处理后,杉木边材的浸注性均显著高于心材的浸注性;具缘纹孔的闭塞率较低以及部分具缘纹孔周缘破裂是高频真空干燥后木材浸注性提高的主要原因. 相似文献
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家具和地板用浸渍改性杉木研究进展 总被引：2，自引：0，他引：2
《林业工程学报》2016,(5)
杉木是我国南方重要的速生林树种之一,但其木材存在诸多缺陷,极大地限制了其在家具、地板中的进一步开发利用。将杉木进行浸渍改性以提高综合利用率是解决全球木材的供需矛盾和家具、地板用材短缺的重要手段之一。浸渍改性目前主要应用的树脂有UF树脂、PF树脂、聚乙烯醇缩甲醛、MF树脂等,其中以PF应用较常见,其改性效果较为显著。浸渍改性过程中,主要有真空处理、真空加压、抽提后常压浸渍或真空浸渍等浸注方法,辊压浸注作为常温常压条件下高效快速浸注处理木材的方法也可用于杉木的浸渍改性,真空-叠压法既能保证改性药剂完全渗入杉木木材,也能防止杉木试材在压力下被压溃。不同的浸渍工艺参数和树脂固化条件对改性后杉木性能影响不同:浸渍时间对浸渍材的吸水率及吸水厚度膨胀率影响较大,热压温度、热压时间与压缩变形恢复率、静曲强度密切相关,各工艺因素间存在一定的相互关系和影响。最后讨论了浸渍改性杉木在家具、地板业中的发展方向与应用前景,为杉木浸渍改性的进一步研究和应用提供参考。 相似文献
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酚醛树脂对人工林杉木木材的浸注性及其改善的研究 总被引：15，自引：1，他引：15
研究了低分子量酚醛树脂对杉木木材的浸注性及树脂在木材内的分布状态，并对苯醇抽提前处理法、常压浸渍和真空浸注的效果进行了评价。无论抽提处理与否，常压浸渍的树脂水溶液充填率为理论最大浸注量的10％左右，而真空浸注可达到90％以上，真空浸注效果明显；无论是常压浸渍还是真空浸注，抽提处理后树脂的浸注性有很大改善，但常压浸渍的效果不是非常明显。软X射线解析样品纵向树脂分布状态结果表明：无论是否经过抽提处理，在常压浸渍的情况下，树脂主要分布在样品的端部，而经过真空浸注处理，树脂注入的深度增加，尤其经过抽提处理后树脂可达到样品中心。由此可见，抽提处理和真空浸注并用，使树脂的分布状态有很大改善。另外，抽提处理后样品之间树脂分布的差异也趋于减小，即树脂在样品间的分布状态也有改善。用实体显微镜观察树脂在木材细胞腔内的充填状况结果表明：沿着样品纵向从端部到中心树脂充填率呈下降趋势，而且抽提处理的充填率比未抽提处理的高。 相似文献
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为探讨浸注工艺对木材增重率的影响,以PF树脂为浸注材料,以树脂浓度、压缩次数、保压时间、浸渍时间和压缩率为试验因素,采用单因素试验方法在平压浸注装置上对杨木试件进行了浸注填充。结果显示:2次压缩较1次压缩,杨木木材增重率增加了20. 2%;保压时间从0 min延长至10 min,杨木木材增重率增加了11. 5%;浸渍时间从1 h延长至2 h,杨木木材增重率提高了8. 8%;再增加压缩次数、延长保压时间和浸渍时间,杨木木材增重率均变化不大;而杨木木材增重率随PF树脂浓度和杨木木材压缩率增加呈线性增加,PF树脂浓度与压缩率对杨木木材增重率具有显著影响。因此选择压缩次数为2次,保压时间为10 min,浸渍时间为1 h,PF树脂浓度与杨木木材压缩率由改性木材的用途决定。 相似文献
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F. Thuvander L. Wallström L. A. Berglund K. A. H. Lindberg 《Wood Science and Technology》2001,34(6):473-480
Drying of wood may lead to readily observable macroscale cracks. Recently observations were made indicating that also at
the level of cell walls, damage occurs due to drying. A method is presented where green wood is impregnated using a solution
of water and a bulking compound such as glycerol. Tensile strength parallel to the grain for wood impregnated in the green
state was compared with that for ordinary dried wood and for wood impregnated after drying. Data demonstrate significantly
higher strength for wood impregnated in the green state. It is postulated that this is due to damage in the cell walls of
non-impregnated wood where the damage is induced by the drying stresses. Support for this hypothesis is also presented in
the form of fractography results. For wood impregnated in the green state, damage development during drying is limited. This
is because the impregnating chemical (glycerol in the present case) in the cell wall substitutes some of the moisture and
therefore limits the drying stresses.
Received 19 November 1999 相似文献
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西南桤木木塑复合材料的研究 总被引：6，自引：1，他引：6
采用乙烯基类系列单体——丙烯腈(AN)、甲基丙烯酸甲酯(MMA)、丙烯酸(AA)三元共聚单体注入西南桤木木材中，制成新型的高分子复合材料(AMA—WPC)。单体的注入用满细胞法，聚合用热引发法，并采用添加氯化锌对木材细胞壁进行活化等工艺对木塑复合材进行了研究和分析。实验样品按照国标GBl927—1943有关规定进行测试，并结合傅立叶红外光谱和扫描电镜探讨了各因素对AMA—WPC材料接枝率及性能的影响。结果表明：改性后西南桤木木塑复合材料具有优异的物理、力学性能。与素材相比较，AMA—WPC的密度提高了59．8％，顺纹抗压强度提高了76．7％，抗弯强度提高了90．4％，抗弯弹性模量提高22．2％，端面硬度提高102．3％，径面硬度提高153．6％，弦面硬度提高152．2％，吸水率降低56．7％，湿膨胀率降低19．0％。 相似文献
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High temperature dried and green wood of Swedish pine was impregnated with glycerate and silver nitrate. TEM and STEM/EDS
on ultramicrotomed specimens was used to reveal the location of silver in the cell wall. The silver was precipitated by a
new method using silver nitrate impregnated after which the wood had been impregnated with potassium glycerate. A significant
difference in the distribution of the silver was observed. In the green wood, there was a homogenous distribution of the impregnant
compared to the dried specimens. The inhomogenous distribution in the dried specimens is believed to be the result of damage
inside the wood cell walls which in turn will have a negative effect on dimensional stabilizing results. The darker compound
middle lamella observed is believed to be an artefact.
Received 19 November 1998 相似文献
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The size and location of silver particles in K-glycerate/AgNO3 impregnated Swedish pine, green wood as well as high temperature dried, have been studied using TEM micrographs.
The diameter of the silver particles was found to be 2–20 nm in the impregnated green wood and as large as 1000 nm (major
axis) for the ellipsoid-shaped silver clusters in the impregnated dried wood. Studying the projected area of the silver particles
in impregnated green wood indicated that there are a lot of particles (40%) in the compound middle lamella with fewer particles
in the S2 (6–8%), S1 (4%) and S3 (2%) layers. The average distance between the silver particles, 50 nm (S2-layer), in impregnated green wood shows that the impregnant is distributed in the cell wall at the microfibrilar level. Experimental
results show that the fastest diffusion path into the cell wall is from the lumen over the pit membrane through the compound
middle lamella and not from the lumen through the secondary wall layer S3.
Received 11 January 1998 相似文献
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为考察杨木和辐射松树脂浸渍材的机械加工性能,参照LY/T 2054—2012《锯材机械加工性能评价方法》,分别对杨木和辐射松的素材与树脂浸渍材及其经过真空热处理的树脂浸渍材的刨削、铣削、钻削、开榫和车削5种机械加工性能进行测试评价。结果表明:1)本试验范围内,在综合评分满分40分情况下,杨木素材、树脂浸渍材和真空热处理树脂浸渍材的总评分分别为20分、30分和25分;辐射松素材、树脂浸渍材和真空热处理树脂浸渍材的总评分分别为24分、33分和29分;树脂浸渍材机械加工综合性能最佳,热处理树脂浸渍材次之;2)杨木和辐射松的树脂浸渍材及其真空热处理树脂浸渍材的刨削、铣削性能均为优秀,车削性能均为良好;杨木和辐射松的树脂浸渍材及辐射松真空热处理树脂材开榫性能良好;钻削性能仅辐射松树脂浸渍材达到优秀;3)辐射松素材与改性处理材的机械加工性能均优于杨木,综合比较,辐射松树脂浸渍材具有较佳的机械加工性能。 相似文献
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在氨水存在下,杨木经苯酚-甲醛低聚物浸渍改性后,尺寸稳定性有了较明显改善,力学性能也有所提高。随着氨水添加量的下降,试样的静曲强度呈单峰型变化,且较未改性的试样均有所提高。当氨水添加量为0.5mol时,改性杨木的综合性能最优,其中,静曲强度相对未改性的参比提高了约6.9%,20℃水泡24h的体积膨胀率相应下降了36.2%,其他性能也相应的有所提升。 相似文献
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The fluorescence characteristics of furfurylated wood studied by fluorescence spectroscopy and confocal laser scanning microscopy 总被引：2，自引：0，他引：2
The fluorescence of furfurylated wood was studied. Furfurylation of wood introduced fluorescent curing products into the cell
walls. Fluorescent products were also found in the lumina if high loadings were used and/or if the wood contained cells with
small radii. More intense fluorescence was obtained from lignin-rich parts of the compound cell wall (i.e., the middle lamella
and the cell corners) than from the secondary cell wall if the wood was impregnated using furfuryl alcohol (FA), while impregnation
using small poly(FA) oligomers showed no or only minor differences between different regions. The study also showed that when
higher amounts of catalyst were added to the impregnation liquid, a red-shift in the fluorescence from the furfurylated wood
was seen, corresponding to an increased conjugation length of conjugated poly(FA) formed within the wood cell wall. Longer
conjugation length than within the cell wall was observed for the poly(FA) formed within the lumina. This indicates that the
cell wall polymers restrict poly(FA) formation. 相似文献
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G. C. Chen 《Wood Science and Technology》1994,28(5):365-370
Summary We are investigating wood decay biocides that are both effective in protecting wood from decay and more environmentally compatible than other biocides. A series of halophenyl sulfonamides were synthesized and characterized by infrared and neuclear magnetic resonance spectroscopy. Wood impregnated with these compounds was tested for resistance to decay as well as water leaching. Wood impregnated with para-iodophenyl or para-fluorophenyl para-tolyl sulfonamides resisted decay by brown- and white-rot fungi. For wood impregnated with para-iodophenyl para-tolyl sulfonamide, threshold retention with the brown-rot fungus Gloeophyllum trabeum was 9.1 mmol/ 100 g solution for unleached blocks. For leached blocks, weight loss was very high (24.6%), which indicated that threshold retention will be substantially higher than 9.1 mmol/100 g solution. With the white-rot fungus Coriolus versicolor, threshold retentions were 2.9 and 5.6 mmol/100 g solution, respectively, for unleached and leached blocks. Leaching of the blocks treated with the iodo compound slightly decreased resistance to decay by C. versicolor. For wood impregnated with parafluorophenyl para-tolyl sulfonamide, threshold retentions with both G. trabeum and C. versicolor were very close to 9.0 and 9.2 mmol/100 g solution, respectively, for leached and unleached blocks. Leaching had a little effect on resistance to decay by both fungi. Wood impregnated with parachlorophenyl or bromophenyl para-tolyl sulfonamide was ineffective in resisting decay by both fungi. 相似文献