A critical discussion of the physics of wood–water interactions

This paper reviews recent findings on wood–water interaction and puts them into context of established knowledge in the field. Several new findings challenge prevalent theories and are critically discussed in an attempt to advance current knowledge and highlight gaps. The focus of this review is put on water in the broadest concept of wood products, that is, the living tree is not considered. Moreover, the review covers the basic wood–water relation, states and transitions. Secondary effects such as the ability of water to alter physical properties of wood are only discussed in cases where there is an influence on state and/or transition.     

Isolation of lignin–carbohydrate bonds in wood. Model experiments and preliminary application to pine wood

A novel method for analysis of benzylic ether type lignin–carbohydrate bonds has been developed by using model compounds. Four diastereomers of model compound 3-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-3-(methyl -d-glucopyranoside-6-O-yl)-1-propanol (GGMGP), were ozonized in acetic acid/water/methanol 16:3:1 for 1h at 0°C. The product from ozonation of each diastereomer was saponified and the corresponding -etherified tetronic acid (TAMGP) was isolated using ion exchange chromatography. Minor amounts of methyl -d-glucopyranoside (MGP) and small amounts of a gluconic acid etherified with tetronic acid (TAGLCA), tetronic acid, gluconic acid, and glyceric acid were detected in the product mixture of ozonated benzylic ether type model compounds. The results suggest that a benzyl ether bond between lignin and carbohydrate is rather stable during the ozone treatment. Acid treatments with sulfuric acid or trifluoroacetic acid of the derived TAMGP led to cleavage of the glucosidic bond but only a small amount of products (tetronic acid and glucose) resulting from cleavage of the -ether bond were formed. The successful chemical treatments were used for studies of benzylic ether bonds in Japanese red pine. The results suggest the presence of benzylic ether bonds to polysaccharides in the wood.Part of this paper was presented at the 10th International Symposium of Wood and Pulping Chemistry (ISWPC), Yokohama, 1999; the 11th ISWPC, Nice, 2001; and as a rapid comunication in J Wood Sci (2000) 46:263–265     

Determination of 2-thiocyanomethylthiobenzothiazole (TCMTB) in treated wood and wood preservative using Ultraviolet–visible spectrophotometer

Ultraviolet–visible Spectrophotometer method for the determination of 2-thiocyanomethylthiobenzothiazole (TCMTB) in treated wood and wood preservative was developed. The determination was done after conversion of TCMTB to 2-mercaptobenzothiazole (2-MBT). This conversion was obtained by reaction with 0.1?M cystein alkaline condition (pH 10). The extraction of 2-MBT was carried out with ethyl acetate containing 0.2% of ?-mercaptoethanol after acidification with 2?M phosphoric acid (pH 2.5). The sample absorbance was measured at 324?nm wavelength with a calibration curve range from 10 to 90?ppm of TCMTB. The Regression value, R ², achieved was 0.9998, while the precision, RSD, was <10% (n?=?6). The recovery was in the range of 90.7–103.2% (n?=?6). The result obtained with this colorimetric procedure is comparable to the HPLC–PDA method.     

Examination of the failure behavior of wood with a short crack in the radial–longitudinal system by single-edge-notched bending test

The failure behavior of wood with a short crack was examined by conducting the single-edge-notched bending tests of a radial-longitudinal system on Agathis specimens. In the test, the mode I critical stress intensity factor was measured, and its validity was checked by the result from double cantilever beam testing method. The mode I critical stress intensity factor decreased when the crack length approached zero. With crack length correction, a constant critical stress intensity factor was obtained over a wide range of crack length including crack-free specimen.     

Chemical modification of simul wood with styrene–acrylonitrile copolymer and organically modified nanoclay

Simul wood (Salmalia malabarica) was chemically modified by treatment with styrene–acrylonitrile copolymer (SAN), glycidyl methacrylate (GMA), and organically modified nanoclay. The physical properties of wood polymer composites (WPC) were improved due to the addition of GMA and nanoclay. XRD analysis indicated a decrease in crystallinity in WPC. FTIR study confirmed the presence of clay in WPC. The presence of clay in cell lumen and cell wall was evidenced by SEM study. WPC containing lower percentage of clay showed better thermal stability compared to WPC loaded with higher percentage of clay.     

Effect of organoclay platelets on the mechanical properties of wood–plastic composites formulated with virgin and recycled polypropylene

Abstract

This study investigated the effects of organoclay platelet contents (0, 3 and 5 wt%) and polypropylene type (virgin and recycled) on the mechanical properties of polypropylene/wood flour composites. Composite samples were made by melt compounding and consequent injection moulding. The tensile, flexural and impact properties of resultant composites were determined. X-ray diffraction (XRD) analysis of composites with 3 and 5% nanoclay content was also conducted. The results indicated that tensile and flexural properties of the composites increased with the addition of nanoclay particles up to 3 wt% and decreased thereafter. The impact strength of the composites, however, decreased with the incorporation of nanoclay. The mechanical properties of the recycled polypropylene-based nanocomposites were statistically comparable with those based on virgin polypropylene. XRD analysis revealed that the degree of intercalation in the nanocomposites containing 3% nanoclay was higher than in those containing 5%. Based on these results, it can be concluded that recycled polypropylene could be used instead of virgin polypropylene in the production of value-added products with no significant adverse effects on the mechanical properties.     

Evaluation of Tsai–Wu criterion and Hankinson's formula for a Brazilian wood species by comparison with experimental off-axis strength tests

Abstract

This article presents a study based on the Tsai–Wu failure criterion as well as Hankinson's formula that evaluates the off-axis strength of wood. For materials such as wood, the strengths are a function of the grain orientation and also are different in compression and tension for the same direction. By considering this anisotropic behaviour, the failure criterion of the Tsai–Wu was adopted in this work. To establish this criterion, the strengths were determined from compressive and tensile tests as well as shear and biaxial compressive tests. In addition, off-axis uniaxial tests were performed, and the experimental results were compared with those obtained by the discussed criteria. In these tests, specimens of Goupia glabra-Brazilian wood species were used. This study's most important conclusion was: the predictive ability of the Tsai–Wu criterion was close to that of Hankinson's formula and fits the experimental results of the compressive and tensile tests well.     

Growth and wood properties of a 38-year-old Populus simonii × P.nigra plantation established with different densities in semi-arid areas of northeastern China

To characterize the effects of plantation densities on the growth characteristics(diameter at breast level,tree height and volume) and the common wood properties,38-year-old Populus simonii 9 P.nigra clones planted with four levels of spacing(2 m × 2 m,3 m × 3 m,4 m × 4 m,and 5 m × 5 m) in a semi-arid area in northeastern China were examined.The results of ANOVA showed significant differences(P0.01) for all the investigated growth traits and wood properties under different plantation densities,except for the chemical composition of wood.The repeatability and phenotypic variations of all the traits varied from 0.34 to 0.99 and from 13.45 to 59.65%,respectively.Except for wood density,which was significantly negatively correlated with the growth traits,a positive correlation was observed between the growth traits and all the other wood mechanical properties.However,most of the correlations between the growth traits and the chemical composition of the wood were not significant.The path analysis for the wood mechanical characteristics and the growth in the prediction of volume were significant and ranged from 0.18 to 0.72 for wood density and diameter at breast height,respectively,while those for the chemical composition of wood ranged from 0.001 to 0.336,which showed a low impact on the volume.The highest stand volume(610 m~3) per hectare was observed with the 2 m × 2 m spacing,which consequently provided a high total price and income,while a high individual volume growth per tree was observed with the 5 m × 5 m spacing.The results suggested that for the poplar trees younger than 40 years in a semi-arid area in China,2 m × 2 m spacing is suitable for obtaining a high volume per hectare,while 5 m × 5 m spacing is best for obtaining a high individual volume per tree.     

Tree–grass interactions for N in Nothofagus antarctica silvopastoral systems: evidence of facilitation from trees to underneath grasses

Nothofagus antarctica forests in south Patagonia are usually used as silvopastoral systems but how grasses and trees compete for specific resources, such as nitrogen in these systems is unknown. To understand interactions between grasses and N. antarctica trees for N, an experiment with ¹⁵N labeled fertilizer was carried out comparing N absorption by grasses growing under trees (silvopastoral system) with an open site. Labeled ¹⁵NH ₄ ¹⁵ NO₃ fertilizer at 10 % atom excess was added in spring at both sites and ¹⁵N was measured in herbage, soil and trees every 30 days during the growing season. Soil was the component that containing the greatest amount of N and greatest ¹⁵N recovery. Grasses growing in the silvopastoral system absorbed almost double of the fertilizer applied than grasses in the open site (32.4 kg N ha^?1derived from fertilizer based on ¹⁵N recovery). Roots were also an important fate for N absorbed, representing 50 and 63 % of total ¹⁵N recovered in grass roots of open and silvopastoral sites, respectively. Trees absorbed 69 % less applied N than grasses in the silvopastoral system; being mainly allocated in small branches, sapwood and fine roots. Overall, ¹⁵N recovery was 65 % higher in the silvopastoral system (tree + grasses) than in the open site (grasses). Silvopastoral system made more efficient use of the ¹⁵N added. These results indicated that N. antarctica trees in the silvopastoral system may “facilitate” fertilizer N absorption of grasses by improving environmental conditions like water availability or by reducing competition for inorganic N between soil microorganisms and plants.     

Quantitative determination of cyproconazole,as a wood preservative,by gas chromatography–mass spectrometry analysis: matrix effect observed in determining cyproconazole and efficacy of adding analyte protectant

Quantitative determination of cyproconazole by gas chromatography–mass spectrometry (GC/MS) analysis was investigated. The results suggest that cyproconazole determination is significantly affected by wood extracts. In the presence of methanol extracts of Japanese cedar (Cryptomeria japonica) heartwood, cyproconazole showed 50 % larger peak area than that without the extracts. This phenomenon whereby contaminants in the sample solution affect the intensity of the peak signal is known as the matrix effect. An investigation for eliminating the matrix effect revealed that adding sorbitol as an analyte protectant drastically increased the analyte peak intensity and successfully mitigated the matrix effect of the wood extracts. Adding hexaconazole as an internal standard was also useful in reducing the deviation of the data. The efficacy of a novel sample preparation method consisting of adding sorbitol and hexaconazole as analyte protectants and the internal standard, respectively, were applied to the GC/MS analysis of cyproconazole in the presence of wood extracts of the other nine species. It is revealed that cyproconazole can be precisely determined by GC/MS analysis in combination with the analyte protectant and the internal standard.     

Adaptation of pine wood nematode,Bursaphelenchus xylophilus,early in its interaction with two Pinus species that differ in resistanceOA

Pine wilt disease(PWD) is one of the most devastating diseases of Pinu s spp. and is caused by the pine wood nematode(PWN), Bursaphelenchus xylophilus(Steiner & Buhrer) Nickle. To study adaptation of PWN to survive in hosts that differ in resistance, we examined the self-regulatory characteristics of PWN at the biological and molecular levels early in the interaction. Two-year-old susceptible Pinus thunbergii and resistant Pinus taeda were selected for this experiment, and changes in PWNs af...     

A review of research on the nun moth (Lymantria monacha L.) conducted with pheromone traps in Czechoslovakia, 1973–1984

A review of research on the nun moth (Lymantria monacha L.) 1973–1984 in Czechoslovakia conducted with pheromone traps is given. By using this method many new results on bionomy, ecology and gradology of this pest could be obtained.