马尾松木材化学组分的遗传控制及对木材育种的意义

本文利用 1 3年生马尾松子代测定林的 2 0个自由授粉家系的木材试样 ,着重研究木材化学组分的遗传学问题。研究结果表明 ,木材化学组分、基本密度和生长性状在家系间的差异都达到了极显著水平 ,并受中等至强度的遗传控制。在 6个木材化学组分中 ,灰分、戊聚糖和 1 %NaOH抽出物含量的遗传力较高 ,木质素、综纤维素和热水抽出物含量的遗传力稍低。生长性状与木材密度呈显著的负相关 ,而与木材化学组分相关性很小 ,似相互独立。遗传相关认为灰分和热水抽出物含量可分别作为综纤维素和木质素的间接选择指标。由于综纤维素和木质素含量在家系间的绝对差异较小 ,仅为 2 %～ 3% ,对选育的实际意义不大。可选择综纤维素含量高的优株进行无性繁殖加以利用     

杉木间伐材高温热处理后化学成分的变化

以空气和菜子油为介质,分别用180,200和220℃处理杉木间伐材2和4 h,测定处理样综纤维素、纤维素、Klason木质素和苯醇抽出物相对含量的变化,并用傅里叶变换红外光谱分析高温热处理过程中木材内综纤维素的变化规律.结果表明:热处理后试材综纤维素含量均有不同程度的降低、纤维素总体降低较少,相应的苯醇抽出物含量、Klason木质素含量增加;温度升高、处理时间延长,木材主要化学组成的变化程度增大;在隔氧的油介质中进行热处理,试件的化学成分变化程度低于空气介质中热处理材;方差分析表明不同温度、时间、介质对主要化学组成产生极显著的影响;FTIR分析表明,180℃热处理时开始发生半纤维素分解,到200℃时纤维素也开始分解;氧气氛围对糖残基的热分解具有促进作用.在3 412,1 050,898 cm~(-1)附近相关糖残基,1 736 cm~(-1)附近相关C=O以及2 907 cm~(-1)附近对应C-H的吸收强度的变化也表征出热处理过程中各化学成分的变化规律.     

云南木竹材材质的研究现状

对人工林木材材质的研究是一个热点,木材的材质直接影响到加工利用,思茅松、巨桉、龙竹和西南桦是我省主要的人工林树种。本文综述云南木竹材(思茅松、巨桉、龙竹和西南桦)的研究现状,培育措施(包括不同造林密度、抚育间伐)和立地条件对木材材质的影响,并指出纤维形态、综纤维素、木质素、戊聚糖、1%NaOH抽出物、苯醇抽出物、生长轮宽度、晚材率、基本密度等影响纸浆材材质的主要性能指标。     

5种不同品系相思木材的化学性质 I.木材化学组成及差异性

对大叶、厚荚、卷荚、马占和黑木等5种不同品系相思木材的灰分、综纤维素、α纤维素、半纤维素、1%NaOH抽出物、苯醇抽出物、多缩戊糖、木质素、相对结晶度等主要化学组成及变异进行了系统的研究,揭示了5种不同品系间相思木材主要化学组成的变异及差异性。研究结果表明:在5种品系的相思木材中大叶相思、厚荚相思和马占相思木材具有基本相同的化学组成;而厚荚相思与卷荚相思、黑木相思之间,马占相思与卷荚相思之间以及卷荚相思与黑木相思之间的主要化学组成均存在不同程度的差异显著性。大叶、厚荚、卷荚、马占和黑木相思木材的综纤维素含量分别为:71 25%、70 84%、75 47%、72 38%和71 77%;α纤维素含量分别为:45 30%、46 47%、50 15%、46 48%和43 99%;木质素含量分别为:22 83%、24 12%、18 54%、21 98%和20 77%;相对结晶度分别为:58 74%、43 36%、43 42%、39 74%和41 89%;1%NaOH抽出物含量分别为:22 02%、21 20%、22 73%、22 00%和26 20%;聚戊糖含量分别为:22 98%、21 20%、24 68%、23 20%和24 72%;苯醇抽出物含量分别为:5 78%、5 38%、6 13%、6 20%和6 25%。     

紫竹不同变异类型的竹材化学成分分析

紫竹因其竹竿色泽能永久保存、竹材工艺性能优良而广泛用于制作竹制品.对一年紫,二年紫和三年紫3种变异类型的紫竹分别截取1年生、3年生和5年生竹龄的竹杆分梢部、中部和基部3处部位进行综纤维素、多戊糖、木质素、苯醇抽出物、1%NaOH抽出物和热水抽出物的化学成分分析,探求紫竹材加工利用及化学利用的合理采伐类型.结果表明:紫竹杆综纤维素、多戊糖、木质素、苯醇抽出物、1%NaOH抽出物和热水抽出物含量范围分别为73.22%～77.85%、14.05%～15.99%、20.31%～24.72%、1.50%～5.73%、23.85%～32.29%和3.63%～8.02%;其平均含量分别为75.24%、15.02%,22.75%、3.22%、27.11%和5.61%.紫竹不同变异类型间综纤维素和木质素平均含量差异极显著;不同竹龄间综纤维素、木质素和苯醇抽出物平均含量差异极显著.     

白桦木材生物制浆的木材腐朽菌菌种选择

采用5种木材腐朽菌,分别对30株天然林白桦木材进行木材腐朽处理,检测并比较腐朽木材和新鲜木材中未质素、纤维素等主耍化学成分的变化。结果表明,木蹄层孔菌腐朽后的白桦木材其重量、木质素和纤维素损失率最高,桦剥管菌次之,白囊耙齿菌最低;木蹄层孔菌腐朽后的白桦木材纤维素含量略高于新鲜白桦木材,其他4种茵腐朽后的白桦木材纤维素含量都低于新鲜白桦木材,其中桦剥管菌和彩绒革盖菌腐朽后的白桦木材纤维素含量较低。木蹄层孔菌腐朽后的白桦木材1％NaOH抽出物含量最低,苯醇抽出物含量中等,纤维素含量最高,木质素含量较低,相比之下它腐朽白桦木材的能力较强,适用于以白桦木材为原料的生物辅助造纸。     

立地条件对毛竹材化学性质的影响

对江西省14个毛竹主产区的毛竹材化学性质进行试验与研究.结果表明：不同立地条件对竹材化学性质有一定的影响,在不同立地条件下,竹材的纤维素含量比较稳定,受立地因子影响较小;综纤维素含量为73.6%,土壤厚度对竹材综纤维素含量影响差异显著;土壤厚度、腐殖质厚和母岩对木质素的影响差异显著;影响戊聚糖含量的主导因子依次为海拔、腐殖质厚和土壤厚度;影响冷水抽出物含量的主导因子依次为海拔、速效P和腐殖质厚,且海拔对冷水抽出物影响差异显著,并随海拔、速效P、有机质以及速效N含量的增大而增大,随腐殖质厚增大而减少;影响1%NaOH抽出物含量的主导因子有母岩、海拔、腐殖质厚和速效K,其中母岩对1%NaOH抽出物含量影响差异显著,1%NaOH抽出物含量随着腐殖质厚增大而减小;影响苯醇抽出物含量的主导因子依次为速效P、土壤厚度和有机质,且速效P对其含量影响差异显著.     

火炬松种源木材化学成分的变异

报道了火炬松种源试验林木材主要化学成分含量的变异，方差分析表明火炬松种源间纤维素，木质素含量无显著性差异，戊聚糖，苯－醇抽出物含量则差异显著；木材主要化学成分含量广义遗传力较低，种源内株间木材化学成分含量变异大于种源间的差异。纤维素，木质素，苯－醇抽出物，戊聚糖含量与种源原产地地理气象因子间相关性不显著。     

酸雨对杨树木材性质的影响

受酸雨危害和未受酸雨危害的杨树木材性质的对比表明：酸雨对杨树生长和木材性质产生显著的影响。与未受危害的健康材相比,危害材的木素和戊聚糖含量相对升高３．７２％和１．４３％,而综纤维素的含量相对减少３．４５％,热水抽出热,苯－醇抽出物和１％ＮａＯＨ抽出物含量明显高于健康材。     

黑木相思木材化学性质株内变异研究

研究我国黑木相思木材化学性质的株内变异规律,为其加工利用提供基础数据。对广东韶关产28 a黑木相思木材进行化学组成测定,其综纤维素(α纤维素、半纤维素)、酸不溶木质素和抽出物(冷水、热水、1%氢氧化钠、苯醇)的含量在株内纵向上的变异规律不明显;相较于边材,心材的综纤维素含量略低,酸不溶木质素含量略高,抽出物含量更高,pH值更低。实际加工利用中需考虑其心材和边材比例对原料化学组成的影响。     

Acoustic emission monitoring during partial compression to detect early stages of decay

Summary The acoustic emissions (AEs) under partially compression were monitored with two softwood and one hardwood specimens in very eary stages of decay by a brown- and a white-rot fungus. Even slightly decayed specimens emitted AEs immediately after beginning of loading, typically when partial compression stress was applied to brown-rotted wood with the flat-headed attachment. With sound specimens of three wood species, only a few AEs were generated until the load reached at the proportional limit. These results suggest that AE monitoring will be one of the feasible means to detect the incipient stages of decay in a field test.The authors thank the Weyerhaeuser Research Grants Program for its aid in this investigation     

In vitro decay of Aextoxicon punctatum and Fagus sylvatica woods by white and brown-rot fungi

Summary The in vitro decay of Aextoxicon punctatum and Fagus sylvatica wood by the fungi Trametes versicolor, Ganoderma australe, Phlebia chrysocrea and Lentinus cyathiformis was studied by the agar-block method, and then the decayed woods were analyzed by chemical and spectroscopic techniques. The results demonstrated the strong resistance of the A. punctatum wood to the brown-rot fungus L. cyathiformis; the resistance might be related to the low S/G lignin ratio in this Austral hardwood. Wood decay by the Austral white-rot fungi G. australe and P. chrysocrea was rather limited, and preferential degradation of lignin was not produced although all the fungi studied increased wood digestibility. The most characteristic white and brown-rot decay patterns were observed during the in vitro decay with T. versicolor and L. cyathiformis, respectively. Trametes versicolor caused high weight losses and reduced the lignin content of the wood, whereas L. cyathiformis produced a preferential removal of xylan. No important changes in the solid-state ¹³C NMR spectra were observed after wood degradation by T. versicolor, but this technique evidenced an increase in aromatic carbon by L. cyathiformis. This increase was higher than that found in the Klason lignin content, suggesting the presence of altered lignin fractions in the brown-rotted wood.The authors are indebted to Prof. H. D. Lüdemann for the facilities at the Institut für Biophysik und physikalische Biochemie (Regensburg), to A. Navarrete (INIA, Madrid) for her collaboration, and to C. F. Warren (ICE, Alcalá de Henares) for her linguistic assistance. The computer program for spectra treatment was developed by G. Almendros (Centro de Ciencias Medioambientales, CSIC, Madrid). This investigation has been funded by the Spanish Biotechnology Program (Grant BIO88-0185)     

The effect of brown-rot decay on water adsorption and chemical composition of Scots pine heartwood

? The effect of brown-rot (Coniophora puteana) decay on the water adsorption capacity and concentration of extractives of Scots pine (Pinus sylvestris L.) heartwood were studied by comparing corresponding properties of decayed and undecayed wood samples.

? The samples derived from 39 felled trees having a large between-tree variation in the extractive concentrations, and subsequently in the mass loss in the decay test. The water adsorption capacity, expressed as equilibrium moisture content (EMC), was measured at a high relative humidity (RH ～100%, 21 °C).

? In contrast to the widely held belief, the water adsorption capacity of brow-rotted heartwood appeared to be significantly higher than that of undecayed heartwood.

? The chemical composition of heartwood was changed radically by the fungus: the concentration of stilbenes, resin acids and free fatty acids decreased, while the concentration of soluble sugars increased as a result of decay. In addition, fungal sugars were found in the decayed samples. The concentration of total phenolics increased, which obviously reflected chemical changes in cell wall constituents other than extractives.

? As a conclusion, the information concerning the hygroscopicity of brown-rotted wood might be valuable e.g. when carrying out repairs on buildings damaged by advanced decay.

     

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。     

热固性树脂真空加压浸注工艺条件的研究

以西南桦和械木为研究对象，探索不同种类的热固性树脂和不同浸注条件与树脂浸入量和改性材尺寸稳定性的关系。研究结果表明，不同树脂，甚至同一树脂对不同树种的木材具有不同的浸注性，其浸入量随加压浸注时间的延长而增加；木材心边材对树脂的接收能力有所不同；木材性能的改善程度因树种和树脂浸入量而异。     

聚丙烯比例对木塑复合材料性能的影响

以木材纤维和废旧聚丙烯塑料为原料,异氰酸酯(MDI)或马来酸酐(MA)为偶联剂,压制木材纤维/聚丙烯复合材料;通过正交试验,研究聚丙烯(PP)用量对木塑复合材料性能的影响.结果表明:PP比例对复合材料的内结合强度、吸水厚度膨胀率、静曲强度和弹性模量有不同程度的影响.在热压时间、热压温度、复合材料密度相同的条件下,在用MDI做偶联剂,PP用量为40%时,复合材料的性能最佳;在用MA做偶联剂,PP用量为50%时,复合材料的性能最佳.     

聚丙烯比例对木塑复合材料性能的影响

通过正交试验,以木材纤维和废旧聚丙烯塑料为原料,异氰酸酯或马来酸酐作偶联剂,压制木材纤维/聚丙烯复合材料,研究聚丙烯(简称PP)用量对木塑复合材料性能的影响。结果表明,聚丙烯比例对复合材料的内结合强度、吸水厚度膨胀率、静曲强度和弹性模量有不同的影响。在热压时间、热压温度、复合材料密度相同的条件下,用异氰酸酯(简称MDI)作偶联剂,聚丙烯用量40%时复合材料的性能最佳;而用马来酸酐(简称MA)作偶联剂,聚丙烯用量50%时复合材料的性能最佳。     

美国山核桃穗条含水率对嫁接成活率的影响

在大理州林业科学研究所试验基地分别对采集后贮藏8h、24h、48h、72h的美国山核桃穗条进行含水率测定,并用不同含水率的穗条进行嫁接试验。结果表明,穗条含水率对美国山核桃嫁接成活率有显著影响。穗条采集后贮藏8h含水率为33．45％,嫁接成活率为28．8％;贮藏24h含水率为32．65％,嫁接成活率最高,为61．3％;贮藏48h含水率为31．44％,嫁接成活率为43．8％;贮藏72h含水率为31．07％,嫁接成活率最低,为25．0％。穗条蜡封最佳时间为采集后1～2d。     

Physical and mechanical properties of wood after moisture conditioning

Some properties of wood (hinoki:Chamaecyparis obtusa) moisture-conditioned by an adsorption process from a dry state and by two desorption processes (from a water-saturated state and from a state with a moisture content slightly below the fiber saturation point) were investigated. The moisture contents of wood conditioned by the adsorption process and by the desorption process continued to approach to one another for the moisture-conditioning period of over 50 weeks. Accordingly, sorption hysteresis should be regarded as a transitional phenomenon that occurs during the process of approaching the true equilibrium, which requires a long time. The wood conditioned by the desorption process beginning from a water-saturated state showed slightly smaller dimensions than those conditioned by the adsorption process with the same moisture content; however, the wood conditioned by the desorption process from a moisture content below the fiber saturation point showed slightly larger dimensions than those conditioned by the adsorption process. The wood conditioned by the adsorption process from a dry state showed a higher modulus of elasticity and modulus of rupture than did the wood conditioned from a water-saturated state with the same moisture content. The mechanical properties of the wood also varied based on the states at which the desorption process was started. This is a notable characteristic of the relation between the drying condition and the mechanical properties of wood.     

Rapid wood liquefaction by supercritical phenol

Wood was rapidly liquefied at the supercritical temperature of phenol. Under these conditions, wood was liquefied by over 90% for 0.5 min, and the combined phenol content of the obtained liquefied wood reached about 75%. The effects of various reaction conditions on liquefaction were investigated. With increases in reaction temperature, phenol/wood weight ratio, and the charged mass-to-reactor capacity (w/v) ratio, the amount of methanol-insoluble residue decreased and combined phenol content increased. The range of molecular weights and polydispersity of the products obtained after the time at which sufficient liquefaction was achieved were from 400 to 600 and from 1.5 to 2.5, respectively. Wood showed a marked decomposition to low molecular weight components early in the reaction, and then the molecular weight increased slightly with increasing reaction time. The properties of liquefied wood were investigated and compared with those obtained with conventional liquefaction methods. Combined phenol content was similar to that obtained by other liquefaction methods, except the sulfuric acid–catalyzed method, which resulted in flow properties comparable to those of other liquefaction methods. The flexural strength of moldings prepared using liquefied wood was also comparable to those prepared by other liquefaction methods.