Fabrication of amphiphobic softwood and hardwood by treatment with non-fluorinated chemicals

Amphiphobic wood has successfully been fabricated using a combination of O₂ plasma surface activation and coating of pre-hydrolyzed methyltrimethoxysilane (MTMS). The effect of O₂ plasma activation on surface chemistry and surface roughness was investigated using X-ray photoelectron spectroscopy and laser scanning confocal microscope profilometry, respectively. Pre-hydrolyzed MTMS was used to impart oleophobicity to both softwood and hardwood samples with tunable hydrophilicity by adjusting the sonication time during pre-hydrolysis. Depending on hydrolysis time, the coated wood samples display wetting behavior ranging from superhydrophilic/oleophobic (immediate water absorption; motor oil contact angles 63.5° for hardwood and 62.4° for softwood) to amphiphobic (water contact angles 104.3° for hardwood and 91.1° for softwood; motor oil contact angles 68.7° for hardwood and 63.9° for softwood), without affecting visual appearance of the wood. For all plasma-activated MTMS-coated wood samples, no absorption of motor oil is observed for several months, indicating stable oil resistance. The intrinsic porosity of wood is also partially retained after coating.     

Micropores and mesopores in the cell wall of dry wood

To investigate micropores and mesopores in the cell walls of dry wood, CO₂ gas and N₂ gas adsorption onto dry wood were measured at ice-water temperature (273 K) and liquid nitrogen temperature (77 K). CO₂ gas adsorption isotherms obtained were used for determining micropore volumes smaller than 0.6 nm by the HK method (Horvath-Kawazoe method), and N₂ gas adsorption isotherms obtained were used for determining the mesopore volume between 2 nm and 50 nm by the Barrett-Joyner-Halenda (BJH) method. Micropores and mesopores existed in cell walls of dry wood, and the cumulative pore volume was much larger for micropores than for mesopores. Micropores in the cell wall of dry wood decreased with elevating heat treatment temperature, and the decreased micropore was reproducible by wetting and drying. Mesopores did not decrease so much with elevating heat treatment temperature. Micropore volumes for the softwood Hinoki and the hardwood Buna were compared. A larger amount of micropores existed in hardwood Buna than in softwood Hinoki, and this relationship was considered to correspond to the difference in thermal softening properties for lignin in water-swollen Hinoki and Buna. This result probably indicates that micropores in the cell walls of dry wood relate to the structure of lignin.     

Wood decaying properties of the termite mushroom <Emphasis Type="Italic">Termitomyces eurrhizus</Emphasis>

Four strains of the termite mushroom Termitomyces eurrhizus collected in Japan were surveyed for their wood decaying properties in three softwood and two hardwood species, in comparison with the white-rot fungus Trametes versicolor and the brown-rot fungus Fomitopsis palustris. All strains of T. eurrhizus degraded only the surfaces of the wood samples, and differences in mass-loss rates between heartwood and sapwood were generally not significant. Higher mass-loss rates were generally obtained in softwood than in hardwood. The results of chemical analyses of decayed wood samples indicated that T. eurrhizus does not have high lignin-degradation ability, even though it is categorized as a white-rot fungus. These results clearly suggest the unique physiological characteristics of T. eurrhizus.     

Differential calometric analysis of wood and wood components

Summary The prolysis of cellulose, hemicelluloses, lignin preparations, and wood was studied by differential calorimetric analysis (DCA) for the range of 25° to 800° C. The test samples included powdered and filter paper celluloses; hardwood xylan; softwood galactoglucomannans, compression wood galactan, and arabinogalactan; a synthetic (DHP), sulfuric acid, Björkman, Brownell, and cellulase lignins; and unextracted and extracted hardwoods and softwoods. Heats of reaction were determined from the DCA thermal transition areas. Distinct differences were found between the thermograms of each hemicellulose and lignin sample. Although wood species could not be separated thermally, hardwood and softwood thermograms differed because of the hemicellulose degradation pattern.Trade names and company names are included for the benefit of the reader and do not imply any endorsement or preferential treatment of the product by the U.S. Department of Agriculture.Formerly Research Technologist, Forest Products Laboratory, Forest Service, U.S. Department of Agriculture. The Laboratory is maintained at Madison, Wis. 53705, in cooperation with the University of Wisconsin. Present address: The Pennsylvania State University, University Park, Pennsylvania 16802.     

The fractal estimation of wood color variation by the triangular prism surface area method

Color variations of the surfaces of fifteen wood species were characterized by fractal dimension of the triangular prism surface area method. Softwood and hardwood indicated apparently different in the mean fractal dimensions of red and green colors. Red color behaved steadier in softwood than in hardwood and green color varied comparatively stronger in hardwood than in softwood. No evident differences between softwood and hardwood were found in the variation of blue color of all the specimens. Following the low-to-high value order of the mean fractal dimensions, three types of combination of red (R), green (G) and blue (B) colors were found: RGB, RBG and BGR. There also existed six types of fractal dimension distribution; namely, plane, included plane, concave, convex, zigzag, and hilly distributions. Fractal dimensions across the grain changed greatly whereas those along the grain became relatively steady. The characteristic difference of color variation was defined for each species, which was inferred to characterize its own unique appearance of surface color. For color matching of wood parts, fractal dimension quantitatively furnishes essential information of color variation in local and overall features. Such evaluation can be efficiently carried out with few measurements along the grain and by detecting a single color (red, green or blue) only. Received 5 May 2000     

The mechanism of the Mäule colour reaction introduction of methylated syringyl nuclei into softwood lignin

Summary Ezo spruce (Picea jezoensis) wood meal and milled wood lignin were successively reduced with sodium borohydride, methylated with methanol-HCl, oxidized with Fremy's salt, reduced with sodium dithionite, and methylated with diazomethane. Permanganate oxidation of the treated milled wood lignin showed that 0.08–0.1/C9 units of 3,4,5-trimethoxyphenyl groups were introduced into the softwood lignin. Although hardwood meal (beech, Fagus crenata) methylated with diazomethane gave a purple-red colour with the Mäule test, the treated softwood meal gave only a dark brown colour. The aromatic nuclei of lignin were broken down by the Mäule treatment. The consumption of permanganate by treated softwood lignin was higher than by hardwood lignin, which suggests that the guaiacyl nuclei were broken down severely. It is proposed that the purple-red colour obtained from methylated hardwood lignin with the Mäule colour test is generated by reaction of syringyl groups which were liberated by -ether cleavage under the permanganate oxidation conditions.     

Assessing VOC emission by different wood cores using the PTR-ToF-MS technology

To date, the chemical composition and the amount and diversity of volatile organic compounds (VOCs) released by different woody plants samples have been measured and characterized through one of the most common techniques, the gas chromatography–mass spectrometry. However, this technique is very time-consuming and requires sample preparation. By contrast, the Proton-Transfer-Reaction Time-of-Flight Mass spectrometry (PTR-ToF-MS) represents an innovative tool able to provide the whole mass spectra of VOCs with short response time, high mass resolution and without sample preparation. This technique is fast, non-invasive, highly sensitive with a rapid detection system and a very low mass fragmentation of the volatile molecules. The goal of this study was to characterize the VOCs profile of different wood sample cores using a PTR-ToF-MS tool and thereafter to assess whether VOC emissions were specific for some groups of trees. VOCs released from core wood samples belonging to 14 different species were analyzed and subsequently, using an advanced multivariate class-modeling approach, the groups (softwood and hardwood) and the different tree species were discriminated. PTR-ToF-MS was able to detect VOCs from wood and to discriminate between hardwood and softwood and among different species. The great potential and the rapidity of this analysis method allow the PTR-ToF-MS to become a commercial standard tool for monitoring VOCs emitted by wood.     

木质饰品常用装饰技法与不同树种材料属性间的关系

木质饰品采用何种装饰技法,与木质基材本身属性间存在着必然联系,不同的装饰技法对木材属性的要求不同.通常圆雕技法对木材的物理力学性质要求较高,常采用硬木材质;浅浮雕、线雕技法常用软木材质;烙画工艺对木质材料的材性、颜色、纹理有所要求,常采用材质较软的浅色、弱纹理木材;重彩工艺则常用浅色、色纯的木材;车木工艺常用纹理通直的木材.     

Selective assessment of duplex heat-treated wood by near-infrared spectroscopy with principal component and kinetic analyses

We selectively assessed the thermal and hygrothermal treatment times of duplex heat-treated samples from the softwood hinoki cypress (Chamaecyparis obtusa) and the hardwood Japanese zelkova (Zelkova serrata) using near-infrared (NIR) spectroscopy with principal component analysis (PCA) and spectral-kinetic analysis. Wood samples from each species were thermally or hygrothermally treated at 120, 130, 150, and 180 °C, and the second-derivative spectra of these samples in the 6300–5450 cm^?1 range, where moisture content has the smallest effect, were then subjected to PCA. The master curve that was calculated by kinetic analysis successfully explained changes in the first principal component (PC1) scores with thermal treatment time for all temperatures. The angles between the PC1 loadings that explained the spectral variation due to thermal and hygrothermal treatment were 79° for hinoki and 80° for zelkova. Thus, calculation of the inner product between the second-derivative spectra of duplex heat-treated wood and a loading vector that explained the spectral variation due to thermal or hygrothermal treatment allowed us to selectively assess the thermal and hygrothermal treatment times.     

Reinforcement of fiberboard containing lingo-cellulose nanofiber made from wood fibers

Wood-based materials are fabricated with adhesives composed of various materials derived from fossil fuels. It is difficult to identify replacements for these chemical adhesives. This study explored nanofiber technologies as an alternative to these adhesives. In this study, we focused on reinforcement effects of lingo-cellulose nanofiber (LCNF) on fiberboards made from softwood and hardwood fiber. We discuss the density effects of reinforcement with LCNF because the density of medium-density fiberboard (MDF), which is widely used for construction, is standardized at about 0.60–0.80 g/cm³. Fiberboards were manufactured with three densities (0.60, 0.75, and 1.00 g/cm³). For softwood fiberboards, the bending properties for LCNF-mixed boards were higher than those for the control fiberboards at all densities. In this paper, control fiberboard means fiberboard with fiber only. For hardwood fiberboards, the bending properties for LCNF-mixed fiberboard for 1.00 g/cm³-density board were higher than those for the control fiberboard. For internal bond strength (IB), the IB for LCNF-mixed fiberboard was higher than that for the control fiberboard. The thickness swelling (TS) and weight change (WC) with water absorption for fiberboards containing LCNF were lower than those for control fiberboards. As a conclusion, physical and mechanical properties of the resulting fiberboards were significantly improved with the addition of LCNF, especially for softwood fiberboards, due to close binding between LCNF and wood fibers.     

竹纤维*经济墙板初探

毛竹经鼓式削片机削片后用锤式打碎机加工成竹纤维。将竹纤维与采用同样工艺制备的针、阔叶木纤维进行纤 维形态对比，并用竹纤维取代木纤维作为混凝土骨科制备经济墙板。试验结果表明1)竹纤维形态优于木纤维；2)竹纤 维墙板可与针叶材纤维墙板媲美，且密度较低；3)用膨润土代替部分水泥可制备轻质经济墙板，轻质经济墙板的密度仅 为普通经济墙板的3／4，且强度及导热性能略优于普通经济墙板。     

The effects of various lignocelluloses and lignins on physiological responses of a lower termite, <Emphasis Type="Italic">Coptotermes formosanus</Emphasis>

We investigated the physiological responses of a lower termite, Coptotermes formosanus, fed on various lignocelluloses and purified lignins (milled-wood lignins, MWLs) from Japanese cedar (softwood), Japanese beech (hardwood), and rice (grass). Termite survival, body mass, and the changes of the symbiotic protists in the hindgut of workers were observed for 4 weeks. The survival, body mass and presence of both Pseudotrichonympha grassii and Holomastigotoides hartmanni in the hindgut of workers fed on rice lignocellulose at the 4th week of observation were significantly lower than those of the workers fed on Japanese cedar and Japanese beech lignocellulose samples, whereas there was no significant difference in Spirotrichonympha leidyi among all the diets. The three purified MWLs, regardless of their structural differences, did not show any significant differences for the termites’ survival or body mass or the survival of all the three protists. The three MWL diets resulted in significantly lower termite survival compared to starvation, although these diets showed no significant effects on body mass or the protist profiles. Overall, lignins are hardly utilized as a nutrient source by C. formosanus workers and are even rather detrimental to termites when fed on solely.     

木材（特征图象）的微机识别

通过对“微机辅助木材识别系统WIP-89”项目的发展和增补,在木材识别方式上有新的突破,即通过木才解剖图象,微机自动识别木材,现已解决针对树材中的早材至晚材,急变和渐变;阔叶树材中的环孔材、半环孔材和散孔材。     

基于小波的木材纹理分频信息提取与分析

通过引入小波方法 ,对木材纹理进行了多尺度的频谱分解 ,并利用所得到的特征向量分析了水平、垂直和对角方向上的木材纹理频率分布特点 ,比较了针叶树材与阔叶树材、径向切面与弦向切面木材纹理的统计差异。并在试验基础上 ,提出了以小波分解子图像能量值的标准差进行木材纹理最佳分解尺度的筛选 ,探索出滤波长度取 8、分解尺度取 2对充分表现木材纹理特征最为适宜。同时还发现可将垂直中高频分量HL和低频分量LL的能量值作为木材纹理区别与归类的重要参数 ,将EHL ELH值作为木材纹理的方向性量度     

Influence of inorganic matter on wood pyrolysis at gasification temperature

The influence of inorganic matter on the pyrolysis of Japanese cedar (Cryptomeria japonica) wood was studied at a gasification temperature of 800°C with demineralization through acid washing. Some influences on the formation of char, tar, and low molecular weight products coincided with results reported at temperatures lower than the gasification temperature. However, the carbonization behavior of the volatile products and the yield of polysaccharide fraction were not able to be explained as a sum of the pyrolysis of cellulose, hemicellulose, and lignin even after demineralization. These results suggest some interactions between wood constituent polymers other than the influence of inorganic matter.     

Curing behavior and adhesion properties of epoxy resin blended with polyhydric alcohol-liquefied <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> wood

Cryptomeria japonica (Japanese cedar) wood was liquefied using polyethylene glycol (PEG-400 and PEG-600)/glycerol as the solvent with H₂SO₄ as a catalyst. The blended epoxy resins were prepared by mixing the liquefied wood with epoxy resin of various weight ratios and used for wood gluing. The results showed that blended epoxy resins could cure under room temperature with an exothermic reaction. DSC thermoanalysis showed that increasing the blending amount of liquefied wood would shift the peak of curing reaction to a higher temperature but with less heat released. Blended epoxy resins had a good dry bonding strength for wood when cured at room temperature. However, curing with heat treatment could improve the wet bonding strength of blended epoxy resins, especially for those prepared with PEG-400-liquefied wood.     

Reaction behavior of wood in an ionic liquid, 1-ethylpyridinium bromide

The reactions of Japanese cedar and Japanese beech in a pyridinium-based ionic liquid, 1-ethylpyridinium bromide ([EtPy][Br]) were studied. Japanese beech was more easily liquefied than Japanese cedar. Hemicellulose is liquefied rapidly, lignin more slowly, while cellulose is partially liquefied. X-ray diffraction analyses on the [EtPy][Br]-insoluble residues revealed that the crystalline structure of cellulose is maintained even after treatment. The difference in liquefaction can be explained by chemical structural differences between softwood and hardwood lignins and hemicelluloses.     

阔叶树木中矿质元素的分布

对矿质元素在阔叶树干内径向和轴向的分布及特点,元素在针、阔叶树内分布的同异性,影响矿质元素在树干内分布的主要因素等作了综合论述.探讨了根据树木年轮的元素含量变化作为评价环境年代变迁指标的有效性.并对树木与矿质元素研究中存在的问题及今后的研究方向进行了讨论.     

Variation of the phenolic hydroxyl group content in wood lignins

Summary The phenolic hydroxyl group content of wood lignin has been determined in situ by a periodate oxidation method for four softwood and six hardwood species. Hardwood lignins, in contrast to softwood lignins, showed a significant variation among different species in this functional group content which decreased with an increase in the proportion of syringyl units in the wood lignin.Financial support from the Empire State Paper Research Associates is greatly appreciated     

Wood specific gravity-mechanical property relationship at species level

Summary Based on the data set of specimen tests on 16 timber species belonging to four distinct wood categories, the specific gravity-mechanical property relationship at species level was examined, and differences in the relationship between species from distinct wood categories were discussed. The linear equation (S =a +bG) was compared with the curvilinear one (S = G) in terms of the goodness at predicting mechanical properties through specific gravity at species level. The specific gravity-mechanical property relationship, to a differing extent, varies with mechanical properties and wood categories. Among three mechanical properties studied, MOR is most closely and almost linearly related to specific gravity, followed by Cmax, whereas MOE is poorly and least linearly related to specific gravity. In general, the relationship between MOE and specific gravity in a species from the ring-porous category is stronger than in a species from the diffuse-porous category. It appears that Cmax in a species from the second softwood category and the ring-porous category is more closely related to specific gravity than in a species from the first softwood category and the diffuse-porous category, respectively. In addition, MOE in a softwood species is generally less related to specific gravity as compared to a hardwood species. Yet, Cmax in a softwood species appears more closely related to specific gravity. Overall, the curvilinear equation is better than the linear one at predicting mechanical properties (especially MOE) in a species.