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.     

The use of an acoustic technique to assess wood decay in laboratory soil-bed tests

This study assesses the changes in elastic behaviour (i.e. modulus of elasticity – MOE) and mass loss of different hardwood and softwood species exposed to decay in laboratory soil-bed tests. Elasticity moduli were determined using conventional static methods as well as a dynamic method based on flexural vibration. The results obtained show a high correlation between dynamic and static bending measurements for all the timber species tested at different stages of fungal decay. Furthermore, the non-destructive MOE assessment proved to be a good tool for the early detection of wood decay. Received 5 January 1999     

Study on Volatile Organic Components from Chinese Fir Wood

Volatile organic chemicals (VOCs) are emitted as gases from certain solids or liquids, which include a variety of chemicals, some of them may have short- and long- term adverse health effects. Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. VOCs are emitted by a wide array of products numbering in the thousands, for example: paints and lacquers, paint strippers, cleaning supplies, pesticides, building materials and furnishings, office equi…     

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.     

Pyrolysis reactions of Japanese cedar and Japanese beech woods in a closed ampoule reactor

The chemical structures of hemicellulose and lignin are different for two distinct types of wood, i.e., softwood and hardwood. Such differences are expected to affect pyrolysis behavior. In this article, the differences are discussed for Japanese cedar wood (a softwood) and Japanese beech wood (a hardwood) pyrolyzed in a closed ampoule reactor (N₂/600°C/40–600 s). Oven-dried samples were used to eliminate the influence of initial water. Demineralized samples (prepared by acid washing) were also used to determine the influence of the minerals contained in the wood samples. As a result, some features were disclosed for secondary char (coke) formation, char reactivity, tar formation, and subsequent decomposition.     

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     

Headspace solid‐phase microextraction gas chromatography–mass spectrometry for the detection of volatile organic compounds released from Ganoderma boninense and oil palm wood

Basal stem rot disease caused by the white‐rot fungus Ganoderma boninense is a major threat to the oil palm industry, and hence, the ability to detect infections at an early stage of development is desired. In this study, a headspace solid‐phase microextraction (HS‐SPME) method coupled with gas chromatography–mass spectrometry (GC‐MS) was employed to analyse the volatile organic compounds (VOCs) released from G. boninense cultures and infected oil palm wood. We examined VOCs released from three types of samples: G. boninense mycelium, oil palm wood and oil palm wood colonized by G. boninense. This preliminary study led to the tentative identification of 57 VOCs, including alcohols, alkanes, volatile acids, ketones, aldehydes, esters, sesquiterpenes and polycyclic aromatic hydrocarbon groups. Aliphatic compounds with eight‐carbon atoms, such as 1‐octen‐3‐ol, 3‐octanone, 1‐octanol and (E)‐2‐octenal, were the most abundant constituents of the Ganoderma samples, whereas furfural and hexanal were the major compounds detected in the oil palm wood samples. Chemometric analyses using cluster heat maps and principal component analyses were used to discriminate between the VOC profiles. The results indicated that the novel method described here could be used to detect Ganoderma disease and, more generally, for chemoecological studies of plant–pathogen interactions.     

Volatile organic compounds from wood and their influences on museum artifact materials I. Differences in wood species and analyses of causal substances of deterioration

Wood is generally used as the interior material in museum storage rooms. Recently, however, the effects of volatile organic compounds (VOCs) from wood on artifacts has become a topic of great concern. The VOCs from four species of wood (western red cedar, spruce, kiri, and sugi) and their effects on artifact materials (two types of metal, seven types of pigment) were investigated using a deterioration-accelerating test, gas chromatography-mass spectrometry, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The results suggested that the influences on artifact materials varied greatly with wood species, and depended on specific components such as hinokitiol or acetic acid rather than the amount of total volatile organic compounds (TVOCs). It is a very serious problem that of the four species of wood, western red cedar (rich in hinokitiol), which has been recommended as an interior material for museum storage rooms, showed the heaviest deterioration on metal samples, and only this type of wood discolored enpaku (white lead) and rokushou (malachite, verdigris). In such storage rooms, museum artifacts should be carefully monitored. When selecting an interior material for a storage room or studying methods of preventing deterioration, it is very important to consider fully the characteristics of wood VOCs, not only the amount of TVOC.Part of this paper was presented at the 24th (Tokyo, June 2002) and 25th (Kyoto, June 2003) Annual Meeting of the Japan Society for the Conservation of Cultural Property     

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.     

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.     

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     

Limitation of XPS for analysis of wood species containing high amounts of lipophilic extractives

Chemical composition of Norway spruce and pine, two softwood species, has been investigated by X-ray Photoelectron Spectroscopy (XPS). Contrary to results previously obtained with beech wood, which allow to obtain information on bulk chemical composition from surface composition analysis, XPS analysis appears to be unsuitable for the characterisation of Norway spruce and pine wood chemical composition. Indeed, chemical compositions calculated from XPS data differ strongly from those obtained from microanalyses which are in good agreement with theoretical composition described in the literature. XPS analysis of both the softwood surfaces indicated high carbon contents explained by migration of lipophilic extractives to the surface under the influence of the vacuum necessary for XPS analysis. Nonvolatile extractives contained in wood were extracted and deposited on glass plates and analysed. Survey and detailed C1s spectra indicated similar signals to those recorded on wood surfaces. This phenomenon was not observed when samples had been previously extracted before analysis. These results strongly evidenced that extractives present in both species are able to migrate through resin canals from the bulk of the sample to the surface when put into ultra high vacuum. XPS presents, therefore, some limits in the case of the analysis of softwood species containing extractives able to migrate to the surface during analysis. This behaviour, difficult to control, could lead to erroneous interpretations due to extractives enrichment of the surface under the effect of vacuum.     

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     

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。     

木质复合材有机挥发气体采样舱

人造板释放的有害挥发气体有500多种,其中,重要气体包括萜烯、乙醛、酮, 苯和甲苯等.东北林业大学在国内率先研制出这种有机挥发气体采样舱,通过一个小的不锈钢环境舱,对复合材料如地板、墙板、涂料和家具制作材料释放的有机挥发气体浓度采样,并制定出相应的取样规程,初步研究实验表明:该采样仓各项性能稳定,采集的样品能够真实反映代表性气体的品种和数量,取样效果明显,该装置具有较高实用价值.     

An improved fibril angle measurement method for wood fibres

A rapid, reliable technique for the observation and measurement of the fibril angle in wood cell walls has been developed. Sonication in the presence of solutions of certain cobalt and copper salts (5%, wt/vol) was found to be most effective in facilitating fibril angle visualisation. Latewood fibre fibril angle, which previously had been difficult to measure, was also visible, though less frequently. This method has been successfully applied to a number of softwood species including coastal Douglas-fir whose prominent spiral thickenings make it difficult to determine the fibril angle by other methods. The method was also used to determine the fibril angle of some hardwood species as well as a non-woody material, flax straw. It can also be used to determine the microfibril angle of pulp fibres although this procedure is less convenient than with wood sections. Received: 24 June 1999     

Effect of heat treatment intensity on some conferred properties of different European softwood and hardwood species

Effect of heat treatment intensity on some conferred properties like elemental composition, durability, anti-swelling efficiency (ASE) and equilibrium moisture content (EMC) of different European softwood and hardwood species subjected to mild pyrolysis at 230 °C under nitrogen for different durations has been investigated. Independently of the wood species studied, elemental composition is strongly correlated with the mass losses due to thermal degradations which are directly connected to treatment intensity (duration). In all cases, an important increase in the carbon content associated with a decrease in the oxygen content was observed. Heat-treated specimens were exposed to several brown rot fungi, and the weight losses due to fungal degradation were determined after 16 weeks, while effect of wood extractives before and after thermal treatment was investigated on mycelium growth. ASE and EMC were also evaluated. Results indicated important correlations between treatment intensity and all of the wood conferred properties like its elemental composition, durability, ASE or EMC. These results clearly indicated that chemical modifications of wood cell wall polymers are directly responsible for wood decay durability improvement, but also for its improved dimensional stability as well as its reduced capability for water adsorption. All these modifications of wood properties appeared simultaneously and progressively with the increase in treatment intensity depending on treatment duration. At the same time, effect of extractives generated during thermal treatment on Poria placenta growth indicated that these latter ones have no beneficial effect on wood durability.     

Strain-softening behavior of wood under tension perpendicular to the grain

Three softwood samples and one hardwood sample were tested under a tension load applied along the radial direction using small clear specimens and the local tension strain was measured using the digital image correlation method. We successfully obtained a stress-strain curve with a strain-softening branch by calculating the stress using the strain distributions in the vicinity where the specimen ruptured. The continuous digital imaging of the specimen proved to be very effective for measuring the strain in quasi-brittle materials such as wood under tension. The nonlinearity of the stress-strain curve was quantified using two parameters representing the deviation from linear elasticity, and the formula of the stress-strain curve was deduced from the interrelation between these parameters. This formula is expressed quite simply by using the modulus of elasticity along the radial direction and another constant that is unique to the material. Part of this article was presented at the 56th Annual Meeting of the Japan Wood Research Society, Akita, Japan, August 2006     

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.     

Chemical emissions from adhesive-bonded wood products at elevated temperatures

Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was employed to examine the chemical emissions from the glued wood samples at elevated temperatures (150, 200, 250, 300, 350, 400, 450, and 500°C). Two wood species, Douglas-fir (Pseudotsuga menziesii) and southern pine (Pinus palustris), one structural adhesive, phenol–resorcinol–formaldehyde (PRF), PRF-bonded Douglas-fir, and PRF-bonded southern pine were evaluated. The volatile compounds with a mass range of 35–300 m/z emitted from the pyrolysis samples were separated by gas chromatography (GC) and identified by mass spectrometry (MS). The results indicated that compared to neat wood and resin film samples, several additional pyrolysis products were observed for the PRF-bonded wood samples including (1) acetaldehyde and butanedial for PRF-bonded Douglas-fir and (2) acetaldehyde, furfural, 2-furanmethanol, butanedial, 2,3-butanedione, cyclopropyl carbinol, 1,2-benzenediol, and 1-(acetyloxy)-2-propanone for PRF-bonded southern pine. These additional compounds were possibly associated with the interaction between wood and PRF resin. The results also indicated that bonded wood products would be less thermally stable than those of neat wood and PRF resin samples.