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1.
The interactions of alkaline copper quat (ACQ) components with the earlywood and latewood tissues of southern pine were investigated. There was a highly significant redistribution of the copper amine component from the earlywood to the latewood during post-treatment fixation at 50°C, which was mainly attributed to diffusion of copper amine from the earlywood into the latewood. A small amount of copper amine redistributed between the tissues and toward the wood surfaces during drying following fixation. The redistribution within the wood was similar whether the preservative penetrated longitudinally, tangentially, or radially into the wood during pressure treatment. This redistribution resulted in lower solubility of copper, and this effect contributes to the overall copper fixation in ACQ-treated wood. The quat component did not significantly diffuse after treatment, and its concentration remained much higher in the earlywood compared to the latewood. 相似文献
2.
Toshiro Harada Hiroshi Matsunaga Yutaka Kataoka Makoto Kiguchi Junji Matsumura 《Journal of Wood Science》2009,55(5):359-366
The weatherability and combustibility of fireretardant-impregnated wood during accelerated weathering for up to 2000 h were
evaluated. The ability of coating to retain fire-retardant chemicals against leaching was also examined using four coating
systems (water-borne or solvent-borne, pigmented or clear, film-forming or penetrating). Furthermore, the distribution of
fire retardants in the specimens was observed by scanning electron microscopy in combination with energy dispersive analysis
of Xrays (SEM-EDX). The fire performance of the specimens during weathering depended on the chemical retention, and was maintained
at a quasi-noncombustible material level if the chemical retention was above 150 kg/m3. The maximum duration of accelerated weathering to keep this retention was 250 h for the uncoated specimens, but increased
to over 1000 h for pigmented coatings. SEM-EDX revealed that the fire retardants were accumulated in the cell lumina throughout
the wood tissues. However, in the uncoated samples, the leaching of fire retardants occurred for surfaces exposed to light
and water, and was observed down to a depth of ∼150 μm after 500 h. The leaching depth extended throughout the specimen after
1000 h. In contrast, the fire retardants still remained in samples finished with a solvent-borne pigmented penetrating coating
even after 1000 h due to their relatively high chemical retention. 相似文献
3.
4.
A study of the surface discolouration of clear coated wood during artificial and outdoor weathering and its prevention using clear coatings comprising organic UV absorbers (UVA) and mineral UV screeners was carried out. It was shown that the use of UVA and UV screeners in clear coatings was very effective in reducing photodegradation of the wood surface. Preliminary irradiation trials with Xenon arc light showed that the UV screener TiO2 led to the least discolouration of the coated wood surface, closely followed by UVA of the hydroxyphenyl-s-triazine class (HPT). The artificial and outdoor weathering trials indicated that UVA of the HPT class stabilised the colour of the wood surface better than UVA of the 2-(2-hydroxyphenyl)-benzotriazole class (BTZ). Comparison of different artificial weathering methods indicated that Xenon arc light weathering showed the best match to the proceeding discolouration of the clear coated wood panels during outdoor weathering. 相似文献
5.
Tetsuya Sano Satoru Miura Hitomi Furusawa Shinji Kaneko Takahiro Yoshida Takashi Nomura Seiji Ohara 《Journal of Wood Science》2013,59(4):307-320
To evaluate the characteristics of wood ash as fertilizer, composition of inorganic elements and the leaching behavior were studied. The leaching behavior was evaluated by three leaching methods using different solvents (water, hydrochloric acid, and acetic acid: Japanese leaching test Nos. 18 and 19 and modified toxicity characteristic leaching procedure prescribed by the US Environmental Protection Agency). The ash composition varied according to raw materials for fuel and ash collection systems. Concentration of Na, Al, Si, and V became higher in bark ashes while that of K became higher in wood ashes. Pb, Cd, Se, and Zn were more volatile and enriched in fly ashes. Of the nutrient elements, K showed high water solubility and its phytoavailability also appeared high, although the amount of water-soluble K was low in bark ash. Ca and Mg had intermediate solubility while P was less soluble in both water and acetic acid. The amount of hazardous substances having leached was low for most, but not all the ashes, in terms of Pb, Cr and As. Nevertheless, the phytoavailability of these hazardous substances after their application to the forest appeared low, due to their amphoteric leaching behavior and the acidity of Japanese forest soils. 相似文献
6.
The leaching of chromated copper arsenate (CCA) components from unfixed wood immersed in water is modeled in three dimensions
using an analytical model of simultaneous diffusion and reaction. Parameters for the model were determined by laboratory leaching
experiments with small uncoated wood samples, departing from previous approaches where diffusion coefficients are measured
in one dimension at a time. The diffusion coefficients and reaction rate constants of Cr6+, total Cr, Cu, and As in unfixed CCA-treated red pine (Pinus resinosa Ait.) and southern pine (Pinus sp.) were estimated, assuming first-order reaction rate equations and independent Fickian diffusion for all components. Estimated
reaction rate constants and diffusion coefficients were not significantly affected by sample dimensions except for very severe
longitudinal leaching from short samples. The predictive ability of the model using diffusion coefficients determined from
immersion of small lab samples was evaluated by leaching experiments in a spray booth of southern pine lumber at 21 and 60°C,
and red pine pole sections at 21°C. The predictive ability of the model was mixed, but in all cases represents a significant
improvement over small-block leaching models which do not account for the diffusive nature of the leaching process. 相似文献
7.
Estimation of lumber yield from a forest inventory is important in determining the optimal utilization of available regional wood supply. In this study, we review existing approaches of lumber yield estimation, including knowledge-based empirical board-foot log rules used in the United States and some regions of Canada, survey-based wood conversion factors, and optimization technology-based computer simulations. Lumber yields estimated from different approaches are then compared using six datasets from a white spruce commercial thinning experiment in Alberta, Canada. Our results indicated that (1) estimated lumber yield can be significantly different when different methods are employed; (2) board-foot log rules often underestimate lumber yield; (3) wood conversion factors represent regional average of lumber yield as a constant and thus are unsuitable for forest inventory-based lumber yield estimation; and (4) optimization technology-based computer simulations can provide the best estimate of lumber yield for a given forest inventory as long as the mill conditions and lumber dimensions from market demand are specified. Forestry investment in applying computer simulation methods should be encouraged in sawmill operations to improve lumber yield and enhance environmental protection, because, for a given amount of lumber, improving lumber yield means reduced demand for harvest operations. 相似文献
8.
Sedric Pankras Paul A. Cooper Lucie Coudert Jean-Francois Blais Guy Mercier 《Wood Science and Technology》2014,48(2):393-409
Remediation of copper-based alkaline copper quat (ACQ) and micronized copper quat (MCQ) wood-preservative-treated weathered southern pine mulch samples by monoethanolamine (Mea) extraction was studied. The potential reuse of Mea extract in ACQ wood preservative application was also evaluated. Continuous column extraction of copper-preservative-treated samples for 32 h, using 12 % Mea removed 66–86 % (between top and bottom of the column) and 65–80 % of Cu, respectively, from ACQ- and MCQ-treated wood. Mea extracts of treated wood could be reused in ACQ-treating solutions that met the American Wood Protection Association standard specifications for ACQ wood preservatives. This was achieved either by mixing the extract with industrial Cu–Mea solution at 1:4 ratio or by adding cupric acetate salt directly into the Mea extract. ACQ-treating solutions reformulated using Mea extracts of ACQ- and MCQ-treated wood performed similarly to wood treated with industrial ACQ solution and freshly prepared solution using cupric acetate. All treated wood had similar penetrations of Cu in wood during preservative treatment, Cu leaching from the treated wood in contact with water, corrosion of nails in contact with treated wood, and ability to protect wood from mold growth. 相似文献
9.
Wood treated with CCB (chromated copper borate) has an expected service life of 20–50 years, depending on conditions of service and method of treatment. After this period, treated wood is discarded as special waste. Due to toxic elements (Cu, Cr, and B) in such treated wood, burning and landfill disposal are not considered as environmentally sound solutions. Chemical extraction seems more promising. The principle of the method is to convert fixed biocides in wood into soluble form and leach them out of the wood. In order to elucidate this process, copper(II) sulfate, potassium dichromate, and CCB-treated samples were leached using five different agents, namely, water, an aqueous solution of oxalic or acetic acid, and an aqueous solution of oxalic or acetic acid with ammonia. Afterwards, the amounts of leached copper and chromium were determined. In a parallel experiment, electron paramagnetic resonance measurements of wet- and dry-leached and unleached samples were performed in order to determine the paramagnetic complexes that were formed. The highest chromium leaching was achieved with the aqueous solution of oxalic acid, as chromium was converted into water-soluble chromium oxalate. While the mixture of oxalic acid and ammonia resulted in the highest copper leaching, EPR observation revealed that in this case water-soluble complexes of copper, oxalic acid, and ammonia were formed. We found out that oxalates formation is not the only mechanism responsible for copper or chromium leaching. High acidity may play an important role too. 相似文献
10.
Leaching characteristics of homologues of benzalkonium chloride from wood treated with ammoniacal copper quaternary wood preservative 总被引：1，自引：1，他引：0
In Japan, ammoniacal copper quaternary wood preservatives type-1 (ACQ-1), which contains copper and benzalkonium chloride
as its active ingredients, is among the most widely used wood preservatives in the pressure treatment of wood. Benzalkonium
chloride (BAC) in commercial ACQ-1 products mainly comprises C12 and C14 homologues. In the present study, the leaching characteristics
of these BAC homologues were investigated using the heartwood and sapwood portions of Japanese cedar, Japanese larch, and
Sakhalin fir treated with ACQ-1 and 1% monoethanolamine (MEA) solution containing equimolar amounts of homologues. Distilled
water (DW) and artificial seawater (SW) were used as leaching media. Consequently, it was observed that the leaching rate
of the C12 homologue tended to be higher than that of the C14 homologue in DW. The leaching of C12 homologues was accelerated
by using SW, resulting in a significantly higher leaching rate than the C14 homologue using SW. It was thought that the difference
in the hydrophobicities based on alkyl chain lengths resulted in these phenomena. However, when the heartwood portion of Japanese
larch was treated with the homologues in MEA, the leaching rate of the C14 homologue was significantly higher than that of
the C12 homologue. 相似文献
11.
J. Rak 《Wood Science and Technology》1976,10(1):47-56
Summary White spruce (Picea glauca) was treated with ammoniacal solutions of various preservatives containing copper, zinc, and arsenic. The wood was then leached in a severe accelerated test and the amount of copper, zinc, and arsenic lost from the wood was determined. The leachability of arsenic depended on the preservative formulation; when the ratio of metal oxide to arsenic oxide was less than 1.25, 35 to 67% of the arsenic was lost, but when this ratio was greater than 1.25 only 1 to 15% of the arsenic was lost. Only small amounts (1 to 4%) of copper and zinc were leached out using any of the tested formulations. Temperature of fixation had only a slight influence on leaching of copper, zinc or arsenic.The technical assistance of Mr. C. D. Ralph is appreciated. 相似文献
12.
ＣＣＢ是一种性能优良的木材防腐剂，但它的抗流失性能不如ＣＣＡ，由于它是水溶性防腐剂，故处理后木材的尺寸亦不稳定。本研究采用在防腐剂中添加聚合物或树脂的方法来提高ＣＣＢ的抗流失性能，使ＣＣＢ处理材的尺寸稳定性大大提高。研究结果表明，在ＣＣＢ中添加少量聚乙烯醇缩醛树脂后，铜、铬、硼的流失与不加树脂相比分别减少５７．６３，７８．５３和９６，４６％；木材湿胀性在弦向减少９１．９７％、径向减少８８．３４％、体积减少８４，２０％；处理材的抗腐力也明显提高。 相似文献
13.
该文使用 6 4kg·m-3 的CCA C木材防腐剂 ,在 11个后处理基准 (其温度为 5 0℃～ 70℃和 5个不同的相对湿度 )条件下 ,研究了固化干燥条件对处理北美红松和南洋松木材的固化速度和化学元素的流失的影响 .实验样品内的液体通过挤压方法被定期检测并分析其六价铬的含量 .调节固化后的样品按美国木材防腐协会E11 97标准进行流失实验 .一般情况下 ,对于大多数基准 ,红松固化比南洋松少、快 ,并且高温高湿的固化条件比低湿度的固化条件导致较快的固化速度和较少的铬和砷的流失 .对于2个材种在 11个固化干燥条件下 ,铜元素的流失没有很大的差异 .所有的CCA化学元素的流失情况 ,红松比南洋松更明显 .更进一步的工作需要CCA处理大尺寸样品 ,优化干湿球温度差 ,以便考察其固化干燥条件对流失的影响 相似文献
14.
The importance of copper/amine based preservatives is increasing. Leaching of copper from wood preserved with these solutions
is still higher than leaching from wood impregnated with copper chromium ones. In order to decrease leaching, different carboxylic
acids (octanoic, 2-ethylhexanoic, decanoic) were added to copper/amine/boron aqueous solutions. An experiment of leaching
of copper from Norway spruce was performed according to the modified standard procedure (EN 1250). Results confirmed that
carboxylic acids significantly improve copper fixation. The best fixation was determined in specimens impregnated with the
preservative solutions consisting of copper, ethanolamine, boric acid and octanoic acid. From such wood, only 1.6% of copper
was leached. 相似文献
15.
Summary Observations on selective absorption and leaching suggest that the chromium fixes the arsenic preferentially to the copper. Although there appears to be no major amount of fixation of copper by arsenic, at the start of addition of arsenic to copper-chrome formulations there is a small but significant decrease in the leaching of the copper suggesting either a small amount of fixation of copper by arsenic or the formation of an insoluble complex of all three components.Maximum fixation of arsenic was obtained when the Cr/As ratio (as salts) was 1.9 or greater. Maximum fixation of copper is not so simply defined but is round about a Cr/Cu ratio (as salts) of 1.7.The area of maximum effectiveness is not coincident with the area of maximum fixation of both copper and arsenic but slightly displaced towards a region higher copper where there is still maximum fixation of arsenic but some loss of copper. 相似文献
16.
杉木生材含水率分布及其对气干的影响 总被引：2，自引：0，他引：2
以人工林杉木为研究对象,研究生材状态下不同厚度锯材含水率的差异,比较含髓心、钝棱与其他类型等3类锯材的含水率差异,建立生长轮宽度与锯材含水率的关系,分析生材状态含水率对锯材气干周期的影响。研究结果显示,25mm和40 mm的锯材含水率差异极显著;含髓心锯材含水率最低,其次是其他类的,最大是含钝棱锯材;随着生长轮宽度减少,锯材含水率增大;生长轮宽度为4 mm时,是生材含水率分界线,即当生长轮平均宽度小于和不小于4.0 mm时,锯材含水率差异极显著;25 mm和40 mm厚不同含水率锯材各2组气干至含水率25%,低含水率锯材较高含水率的气干周期分别缩短57%和66%。 相似文献
17.
Paul Filson Benjamin E. Dawson-Andoh Laurent Matuana 《Wood Science and Technology》2009,43(7-8):669-678
Rigid polyvinyl chloride–wood flour composite lumber containing either pine or maple wood flour and pine and maple lumber was subjected to accelerated weathering according to the ASTM Standard G 53 protocol. Non-weathered and weathered surfaces of all specimens were analyzed using colorimetric methods, reflectance infrared Fourier transform and Raman spectroscopic techniques. In the FT-IR spectra, conjugated ketones (1,744 cm?1) of lignin as evidenced by their skeletal vibrations (1,560–1,500 cm?1) and stretching (1,440–1,500 cm?1) were reduced in weathered specimens. Cellulose was largely unaffected by weathering. C–O bending vibrations at 1,040 cm?1 from holocellulose in pine specimens and intensity bands at 1,125–1,090 and 1,360 cm?1 (C–O stretching and O–H bending from cellulose) in the maple and wood–plastic composite (WPC)-maple specimens were unaffected. A band at 1,650 cm?1 became prominent after weathering of both pine and maple WPC specimens which is due to C=C–C=C stretching vibration of weathered PVC portion of the specimen. Raman shifts at 530 and 840–900 cm?1 are attributed to C–O and C–C–O stretching in cellulose (remain unchanged). The role of extractives in weathering of pine is shown by the disappearance of Raman shifts at 392 and 434 cm?1 (C=C deformations in pine extractives) in weathered pine. One-Way ANOVA, between-group designs showed significant effect on brightness (L*), redness (a*) and yellowness (b*) for all treatments. 相似文献
18.
In order to improve the leaching resistance of active ingredient-copper in ammoniacal copper quat-type D (ACQ-D) treated Chinese fir (Cunninghamia lanceolata Hook.),microwave post-treatments were carried out.The percentages of leached copper from ACQ-D treated Chinese fir with different microwave post-treatments were obtained after leaching tests by analyzing the copper retention in treated wood.The fixation mechanism of copper in the treated wood was determined with the help of SEM and FTIR spectra,while t... 相似文献
19.
ABSTRACTCertain important quality parameters of red maple (Acer rubrum) laminated veneer lumber (LVL) impregnated with three waterborne formulations: copper azole (CA-B), micronized copper azole (MicroCA or MCA) and alkaline copper quaternary (ACQ-D) bonded with phenol formaldehyde or cross-linked polyvinyl acetate (XPVAc) adhesives were evaluated. Pre-dipping of veneers before LVL production and two post-manufacturing procedures, viz., vacuum-pressure and post-dipping of LVL, were applied. Maximum copper retention in pre-dip-treated, vacuum-pressure and post-dip-treated LVL was 1.4, 9.7 and 1.7?kg/m3, respectively. Copper retention in MCA-treated LVL was relatively lower than soluble formulations. Various physical, mechanical and bonding properties of treated LVL such as density, water absorption, swelling, flexural properties, hardness, tensile shear strength, delamination and wood failure (%) were studied and compared with untreated LVL. Little to negligible deleterious effect was observed on properties of LVL due to these chemical treatments. Analysis of variance results showed that most of properties of red maple LVL were not significantly different compared with those of untreated LVL. Therefore, vacuum-pressure impregnation process can be used to treat the red maple LVL with novel micronized copper formulations for increasing the service life of such products against biodegradation without affecting techno-mechanical quality parameters. 相似文献
20.
In this research, acoustic emission technology was used to estimate the moisture excluding effectiveness of coatings on wood.
Moisture interaction with wood causes damage, and coatings such as paints and varnishes can effectively limit this interaction.
Over time, the moisture excluding effectiveness of wood is reduced by the actions of weathering and the resulting wood-water
interaction leads to problems due to the dimensional instability of the wood. Five coating types, at two spreading levels,
were applied to samples of southern yellow pine. The samples were exposed to three weathering conditions to simulate the effects
of exposure then immersed in water while the moisture interaction was monitored using acoustic emission monitoring equipment.
Cumulative counts as well as changes in size and moisture content were measured or calculated. The results show that acoustic
emission technology is an effective and sensitive estimator of the moisture excluding effectiveness of coatings on wood. The
acoustic emission method is sensitive to local changes and coating fractures whereas the more traditional methods are sensitive
to gross changes in sample characteristics. Of five coatings tested, the most effective one was found to be an oil-based paint,
and the worst performance was by a water-based, clear poly-urethane.
Received: 10 September 1998 相似文献