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Stability and performance of tributyltin compounds
1984 - IRG/WP 3275
Based on the critical examinations of the disputable permanence of tributyltin compounds in wood, this paper deals with a number of examinations of the relative evaporation, thermal stability and oxidation stability of some TBT-compounds. While thermal and oxidative stability is high for all TBT-species, the relative evaporation at elevated temperature is highly variable, and lowest for the TBT-esters examined. Evaporation measurements on treated wood confirm this order of precedence and stress the importance of the preservative formulation. The results also indicate that TBTO evaporates 2-3 times faster than TBTN. It is established that at high retention of TBT in wood the decomposition is slower than at low retention. This fact combined with the extra high retention of TBT in vacuum treated joints of window frames explains the fine record of non-failure for such windows, and the paper ends up with a calculation indicating the presence of sufficiently high amounts of tributyltin for effective fungicidal protection of Nordic class B impregnated windows for at least 20 years.
F Imsgard, B Jensen, H A B Landsiedel, H Plum


Depletion of boron and copper from CCB treated test specimens using different leaching protocols
2004 - IRG/WP 04-50208
The objective of this study was to measure the depletion of inorganic wood preservative components regarding the proposed OECD guideline "Estimation of emissions from preservative-treated wood to the environment: laboratory method for wooden commodities exposed in the use class 4 and 5" as part of the project "Investigations concerning the influence of test parameters on the release of biocidal actives from treated timber in leaching tests". Pine sapwood specimens (50x10x150) were pressure impregnated with CCB according to European Use Class 4. Before leaching all samples were stores 4 weeks for fixation. In addition leaching tests were performed according to the European Standard EN 84 by means of EN 113 blocks. Parallel investigations were carried out between two laboratories to assess the repeatability and comparability of the methods. The results of chemical analysis of leachates taken at different time intervals show that similar depletion rates were determined for copper and boron independent on the leaching protocol used. However, the loss of copper as well as chromium in short term dipping experiments was often lower than the detection limit. Furthermore it can be stated that the difference between parallels was higher for the results which were obtained for the OECD guideline that EN 84. A comparison of both laboratory results indicate that a quite good repeatability is given in case of the CCB treated material.
E Melcher, R-D Peek, U Schoknecht, R Wegner


Rates of emission from CCA-treated wood in the marine environment: measurement, modelling and requirements for further research
2001 - IRG/WP 01-50166-12
Accurate estimates of rates of emission of leachate from preservative treated wood are crucial for realistic predictions of the environmental impact of its use in maritime construction. Estimates are available for some commonly used preservatives, but these vary widely. Though variable, these measurements suggest that emission generally decreases exponentially with time. Part of the variation is due to differences in methodology employed. Physical and chemical characteristics of the seawater used (e.g. temperature, salinity, pH and oxygen content) affect emission rate. So too do the specifics of the treatment process especially the preservative formulation used, and pre- and post-treatment handling of the wood. The nature of the treated wood samples is also important, with misleadingly high estimates being obtained from samples with unrepresentatively high proportions of cross-cut surfaces. A suggested strategy for developing an informative and standardised methodology is discussed. To form useful models of impacts of leaching, emission rates need to be considered in conjunction with site-specific information regarding a) water exchange rates between the area where leaching occurs and the sea, and b) the extent of partitioning of leachate between the water column, biota and sediment. The risk of environmental impact may be reduced by modification to treatment procedures and by careful planning of installation.
S M Cragg, C J Brown, R A Albuquerque, R A Eaton


Blue-stain fungi (Ceratocystis spp.) found in Spain on pine woods
1989 - IRG/WP 1410
So far, there is only a very limited reported description of the different Ceratocystis spp. present on fresh wood in Spain. So, the main goal of this work has been the identification of species of this genus causing blue-stain on Pinus pinaster A. Ait. and Pinus sylvestris L. woods. We have also investigated the relationship between the species found and their propagation vectors (insects and wind). Finally, we have determined the growing velocity of two of the most representative species found and the presence or absence of degradative enzymatic activities.
M T De Troya, A M Navarrete


Analysis of creosote posts after 40 years of exposure
1994 - IRG/WP 94-50035
In the early 1950s The Western European Institute for Wood Preservation (WEI) started a program for testing creosote and salt treated posts in three exposure sites in Europe. Of these only the site in Simlångsdalen in south western Sweden remains today. The purpose with this investigation was to demonstrate which creosote components are still retained in the posts after 40 years of exposure and which components have migrated or evaporated. Three posts, impregnated with three different creosotes, from the site in Simlångsdalen have been studied. The retention, composition and distribution of creosote in the posts have been determined and compared with data on the original creosote. After 40 years of exposure creosote loss is greatest in the post impregnated with creosote containing the highest fraction of low-boiling constituents. The loss is greatest in the top sections of all three posts. The concentrations of low-boiling compounds (b.p. < 270°C), e.g. naphthalene and 2-methylnaphthalene are very low. The residual creosotcs have the greatest percentage of high-boiling constituents (> 315°C), especially phenanthrene and anthracene (b.p. 340°C). The soil close to those posts which were "over-loaded" with creosote during the treatment process, contains increased concentrations primarily of the heavier components fluoranthene, pyrene and chrysene. The small number of posts analyzed limits the possibility to generalize the conclusions.
G Bergqvist, S Holmroos


Response of laboratory groups of Reticulitermes speratus (Kolbe) to different quantities of food
2003 - IRG/WP 03-10489
As part of a project aimed at improving understanding of the foraging biology of Japan’s most widespread wood-destroying termite, different sized groups of Reticulitermes speratus (0.5; 1 and 2 g) from two colonies were kept on 16 or 64 cm3 of sapwood of Cryptomeria japonica for 12 weeks in the laboratory. Patterns of wood consumption, wood consumption rates and survival are discussed.
M Lenz, T Yoshimura, K Tsunoda


Depletion of wood preservatives after four years' marine exposure in Mt. Maunganui harbour, NZ
1994 - IRG/WP 94-50036
This paper reports on chemical analysis of marine test samples exposed in Mt. Maunganui harbour, New Zealand from 1977 to 1981. Depletion data for a Class II CCA, a CCA-A formulation, acid copper chromate and ammoniacal copper arsenate are presented. The results suggest differences in the rate of loss of individual preservative components among the four formulations and redistribution of individual preservative components within the wood.
K J Archer, A F Preston, C M Chittenden, D R Page


Creosote immersion treatments in fence-posts of Castanea sativa, Pinus nigra and Pinus halepensis
1988 - IRG/WP 3488
The method of soaking in creosote was applied to fenceposts of Castanea sativa, Pinus nigra and Pinus halepensis, taking into account its easy use in the field. Absorption, retention and penetration rates were recorded and analysed. Absorption rates were higher in Pinus nigra than in Pinus halepensis, and lowest in Castanea sativa. Thin fence-posts always absorbed more preservative than thick ones. Penetration rates were similar in both pines, and much higher than in Castanea sativa. Retention levels were almost the same in Pinus nigra and Castanea sativa, and lower in Pinus halepensis.
C De Arana Moncada


Performance of chromated copper arsenate-treated aspen fence posts installed in Forintek's Eastern test plot from 1951 to 1963
1984 - IRG/WP 3272
Aspen poplar fence posts were pressure treated by the full cell process using three formulations of copper chrome arsenate wood preservative. A total of one hundred and fifty nine of the posts were installed in service in Forintek&apos;s Chalk River post plot from 1951 to 1962. During the 1982 general inspection of the post plot all 159 posts were still in service. A groundline inspection was carried out on the material to determine the extent to which decay had progressed during this period. Samples were taken from the surface of tanalith C treated posts and subsequent microscopic examination revealed that soft rot attack was present in the outer portion of posts. The groundline area of posts treated with (K 33), CCA type B and (greensalt) CCA type A were in generally good condition after 22 years and 31 years respectively. Rate of decay was highest for CCA-C tanalith treated posts at 0.3 mm per year with a retention of 3.04 kg/m³ oxides.
C D Ralph


Water-repellent additive for CCA
1991 - IRG/WP 3655
Hickson have developed a water repellent additive for incorporation into copper-chromium-arsenate timber treatment solutions. The water repellent emulsion shows good stability in the treatment solution, is easily incorporated and applied in a single stage treatment. No modifications to the additive is safe to treatment schedule are usually needed and use. Weathering of the treated wood is substantially inhibited by the presence of the additive. Adhesion of paints is not affected.
P Warburton, R F Fox, J A Cornfield


Comparison of decay rates of preservative-treated stakes in field and fungus cellar tests
1980 - IRG/WP 2135
With the exception of acid-copper-chromate, zinc-chrome-arsenate, and sodium pentachlorophenoxide, the relative performance of preservatives in the fungus cellar was similar to that in the field.
M E Hedley


Polyflavonoid tannins - From a cause of CCA soft-rot failure to the "missing link" between lignin and microdistribution theories
1986 - IRG/WP 3359
Polyflavonoid tannins are proven to be fast-reacting with CCA solutions and hence, to be strong competitors of the structural wood constituents for fixation of CCA preservatives. The consequence of this effect is that even relatively small amounts of tannin cause severe undertreatment of the structural wood constituents which in turn badly affects the long term durability of CCA-treated timber. The effect is compounded by heavy disproportionation between tannins and structural wood constituents of Cu, Cr and As. This leads to the well-known high susceptibility to soft-rot attack in Eucalyptus species and in vineyard posts even experienced with some susceptible softwoods. Relationships found by other authors between soft-rot incidence and lignin content in CCA-treated timber are shown here to be only part of the total failure mechanism. The total mechanism of resistance and failure is due to the balance of distribution of reactions among the various proportions of highly reactive tannins and more abundant but less reactive lignin and carbohydrates present in any wood. As a consequence of the clarification of these mechanisms the liability of different woods to soft-rot attack may then be determined. Solutions to the problem are presented and discussed. Lignin and microdistribution theories are shown to be both correct and different facets of a single unified theory. Better-performing CCA formulations for tannin-containing softwoods are proposed and proved to be effective. Directions under investigations for better performing CCA formulations for hardwoods are discussed. Inorganic waterborne preservatives formulations "precipitating", not "fixing", such as simple CrIII arsenates or ammoniacal copper arsenites, can be deduced to be better suited for Eucalyptus preservation than CCA itself.
A Pizzi, W E Conradie, M Bariska


Comparison of decay rates of preservative-treated stakes in field and fungus cellar tests. Results after 40 months fungal cellar exposure
1983 - IRG/WP 2200
Decay rates of preservative-treated Pinus radiata stakes during 40 months exposure in the FRI fungus cellar were compared with those of similarly treated material in a field test. Decay rates in the fungus cellar were from 4 to 100 times higher than in the field, although for the majority of preservatives the rate was between 7 and 12 times higher. The lag phase before onset of decay, noticeable with most of the preservatives in the field test, was largely eliminated in the fungus cellar. Possible reasons are given for inconsistencies in relative rates of decay of preservatives in the two tests.
M E Hedley


Sludge formation in timber treatment with CCA preservatives. Origin and elimination
1984 - IRG/WP 3276
The exact distributions between lignin and holocellulose and retentions on wood of copper, chromium and arsenic as a function of various sets of conditions in a factorial experiment in which combinations of three temperatures of treatment, three CCA solution concentrations, four pH&apos;s of the initial CCA solution and two timber species, namely Pinus radiata and Eucalyptus grandis, are reported. Temperature and concentration appear to have an equally important effect on the preservative chemicals retentions and distribution in timber. pH, has also an effect but somewhat less marked than temperature and concentration, with the exception of the formation of sludges. Multivariable regression equations describing the amounts of Cu, Cr and As fixed on lignin and holocellulose for both pine and eucalyptus are also presented. The timber species treated also appears to have an important influence on the amounts of chemicals fixed and their distribution. Eucalyptus appears to be much less tolerant than pine to extremes of treating conditions. The influence of treating time under the most common treating conditions is also briefly discussed.
A Pizzi, W E Conradie, A Jansen


The influence of gaseous oxygen concentration on fungal growth rates, biomass production and wood decay
1998 - IRG/WP 98-10283
The effects of air and several levels of oxygen balanced with nitrogen (% oxygen (v/v) nitrogen to 100%) on growth rates, biomass production and wood decay were investigated. The best technique for measuring daily growth rates in anaerobic jars was found to be by using 40 mm petri dishes which were attached to the walls of the jars. At the end of the test period the same petri dishes were also used for determining the dry weight of the fungal mycelia. The results showed that 5% oxygen concentration was very favourable for white rot and brown rot fungi (Basidiomycetes). When oxygen levels were reduced from 1% to 0.01%, the growth rates and dry weight of these fungi were steadily decreased. On the other hand, there was a large difference between very low oxygen levels (0.01 to 1%) and other levels (5 to 21% 02). In the case of other fungi there was not a big difference on their growth rates and biomass. Observational and numerical results on Fagus sylvatica (beech) and Pinus sylvestris (Scots pine) degradation by Coriolus versicolor, Coniophora puteana and Chaetomium globosum showed that there was a large difference in the degradation of the wood samples caused by C. puteana and C. versicolor when exposed to air and other levels of oxygen (0.25,1, 5 and 10% 02). Weight losses obtained by C. globosum as a soft rot on timber specimens in air and other oxygen levels were all in same range and below 5%. On the other hand there was a safety point at 5% 02 below which the fungus was unable to degrade beech. This point was 10% 02 for scots pine. At these points, weight losses were under 5%.
S M Kazemi, D J Dickinson, R J Murphy


An investigation into the influence of soil cation exchange capacity on preservative component depletion
1994 - IRG/WP 94-20050
The mobility of preservative components from treated wood into the soil environment is regarded as an important determinant of preservative performance. Standard procedures for the investigation of this phenomenon have not been developed to any great extent. Soil bed studies conducted in this laboratory using natural soil and modified soil media have provided interesting comparative data on the influence of cation exchange capacity on preservative depletion. Some of these data are discussed with reference to the development of a standard soil contact depletion procedure.
K J Archer, L Jin


Sampling rates and the probability of detecting defective treatment in the sampling of preservative treated timber
1987 - IRG/WP 2277
When attempting to enforce standards of penetration and retention set for treated timber, the regulating authority must establish a sampling or inspection scheme which will prevent large quantities of substandard product entering the market. On the other hand, the scheme should not penalise treaters for the small quantities of such material which are inevitably produced by any industrial process. Thirteen alternative sampling schemes which could be used to periodically sample individual treatment plant production are compared. The risk of allowing continued production of excessive unacceptable material is compared with the risk of unfairly penalising the treater for producing only small amounts. Schemes are evaluated in terms of the effect of sample size, number of permissible failures at each sampling, and number of warnings issued before taking action. Schemes which present the best balance between opposing risks are identified.
M J Kennedy, L E Leightley


Effect of soil parameters on biocide depletion: laboratory and field studies of water- and emulsion-borne preservatives
2000 - IRG/WP 00-30234
Two field test sites with different soils were selected. Soil analysis showed that the soil at the two sites had considerable texture, base saturation, acidity, and cation exchange capacity differences. Five sets of field stakes were treated as follows: three with water-borne CCA to about 0.4 pcf (6.4 kgm-3) retention, one with 0.75% DDAC, and one with 0.75% DDAC:0.25% chlorothalonil. The last two sets were treated using oil-in-water emulsions. Samples from all five sets were installed at both field sites. In addition, wood samples which had been co-treated with the five sets of field stakes were installed in a lab environment in fungus cellar tubs using soils from the two sites. All wood samples were defect-free southern yellow pine (SYP) sapwood, with the field stakes measuring 19 x 19 x 457 mm3 and the fungus cellar samples measuring 5 x 19 x 250 mm3. The field samples were exposed for two or three years and the fungus cellar samples for 36 weeks, after which depletion of the various biocides was measured. No consistent pattern in CCA depletions between the two soils were observed in either the fungus cellar or field exposure tests, despite the large chemical and physical differences between the two soils. The fungus cellar method may be useful to conduct relatively rapid depletion studies. The authors also discuss problems with depletion studies, including possible influences by soil, wood, and microorganisms present in the soil.
T Schultz, D D Nicholas, D E Pettry, M G Kim


Variation in infection rates of blue-stain, mould and white rot tropical fungi on mixed light Malaysian woods
2000 - IRG/WP 00-10334
The modified 3-week FRIM laboratory method for screening of anti-sapstain formulations against three representative tropical fungi causing blue-stain (Botryodiplodia theobromae), mould (Paecilomyces variotii) and white rot (Schizophyllum commune) infection of sapwood species was used to examine the relative resistance of the sapwood of eight mixed light Malaysian woods, Scots pine (Pinus sylvestris), medium density fibreboard produced from Rubberwood (Hevea brasiliensis) and the heartwood of Sentang (Azadirachta excelsa), to infection by these organisms. After 21 days it was found that Ramin (Gonystylus spp.), Rubberwood, Mersawa (Anisoptera sp.), Ludai (Sapium spp.), Yellow meranti (Shorea spp.), Scots pine and Jelutong (Dyera costulata) were highly susceptible to the pooled combinations of blue-stain, mould or white rot infection often sustaining >50% overall mean fungal coverage or when at least one of the infection types has reached maximum mean coverage (75.5%) of the wood samples. However, the Rubberwood-based fibreboard, and particularly Sentang, and the softwood Agathis spp. from Kelantan (trade name: Damar minyak) and Sarawak (trade name: Bindang), were relatively moderately susceptible to infection, sustaining between 9 and 47% overall mean fungal coverage after 21 days, or even considerably less susceptible (5 - 20% overall coverage) after 14 days. There was absence of both blue-stain and white rot fungal growth on all samples dipped in a low (0.03%/0.03%) fungicide concentration of a MBT/TCMTB anti-sapstain formulation. Such laboratory test results could have significant implications to field or industrial sapstain control of sapwood timbers concerning the lag time between tree felling and anti-sapstain treatment and seasoning.
A H H Wong, S Ahmad


Estimation of oral toxicity of boron as a bait toxicant and the trophallactic effects between individual members of termite colonies.
2003 - IRG/WP 03-10495
In recent years, because of the favourable environmental characteristics of boron, researchers in the wood preservation industries have refocussed on the use of boron as a major wood preservative against wood-destroying insects. Currently the greatest use of boron compounds is in remedial treatments. Boron has been found to have slow-acting toxicity against subterranean termites. Because of this characteristic, boron compounds may also be used as termite bait toxicants. The effect of boric acid on an individual donor termite was investigated in laboratory bioassays Trophallactic transfer of boron by these individual termites to other orphaned group of termite workers was conducted and the effects on the recipient groups recorded. It was believed that, this sequence of tests would provide a greater understanding of the carrying ability of ‘bait toxicant’ by individual termites, and allow estimates of the threshold toxicity of boric acid and termite survival rates to be determined. The bait matrix was Eucalyptus regnans F. Muell sawdust impregnated with various formulations of boric acid solutions in the laboratory. The result suggests that the toxicity of boron is dose dependent and it critical for the termites to ingest sufficient amounts of boron. But the mode of toxicity of boron has not yet been fully explained.
B M Ahmed


Black Stain of Western red-cedar by Aureobasidium pullulans and its Relationship with Tropolone Depletion
2005 - IRG/WP 05-10564
Western red-cedar is valued for its natural durability conferred by fungicidal tropolone chemicals. However, weathered surfaces of WRC products are still susceptible to ‘black stain’ caused by fungi such as Aureobasidium pullulans. The effect of weathering on the tropolone content of heartwood was characterized and correlated with the ability of this fungal species to colonize the same weathered surfaces. UV plus water spray severely reduced tropolone content but did not lead to increased fungal colonization compared to un-weathered wood. When WRC was treated with UV only, the tropolone content was less affected but the fungal colonization increased significantly. A.pullulans exhibited high tolerance to the tropolone &#946;-thujaplicin in vitro; thus loss in tropolone content may not be required for colonization. In addition to UV resistance from melanization and ability to use lignin breakdown products as a carbon source, resistance to tropolones may confer considerable competitive advantage to A.pullulans growing on WRC exposed to weather. The application of water spray most likely washed away products of lignin photo-degradation, leaving the wood surface void of accessible carbon sources which resulted in decreased colonization.
R Chedgy, R Daniels, P I Morris, C Breuil


Losses of preservatives from treated wood during service. Results from a questionnaire
1994 - IRG/WP 94-50031
From environmental as well as from performance point of view it is of interest to know how much of the preservatives in treated wood that is leached out or evaporated from the wood during service. Many laboratory studies are carried out on leaching from small samples in distilled water or water with different pH. These studies give a good picture of the relative leaching from wood treated with different preservatives, but the results are only true for the actual conditions and not representative for treated wood in service. In many reports on studies concerning treated wood in service the remaining preservatives are analysed, mainly to get to know if the remaining amount of preservatives can prevent the wood from biological attack. Seldom is the initial preservative retention known and therefore the leached amount is not known. To get more facts a questionnaire on leaching during service was sent out to all IRG-members in 1991. 29 answers were received, most of them in form published documents but also information from some unpublished studies. Many of the answers concern results from analyses of field test stakes and very few results from analyses of treated timber in constructions. In some cases laboratory studies of leaching are reported in the same documents. Several documents report only on laboratory experiments. All relevant results are put together in Table 1. Reports only referring to laboratory studies are not included. The reports in Table 1 are in the same order as they were received. In Table 2 all results concerning CCA are put together. These results give a good picture of the difficulties to draw conclusions on leaching during service.
M-L Edlund


Factors affecting decay rates in a fungus cellar II
1986 - IRG/WP 2259
Tests were initiated to investigate the influence of various factors on the decay rate in a "Fungus Cellar". Birch and pine stakes treated with chromated copper arsenate and didecyldimethyl ammronium chloride, as well as untreated control stakes, were incubated in two soils in a Fungus Cellar test and installed at two field sites for comparative purposes. The visual rating vs actual stake weight loss relationship was also studied. Preliminary results from the initial Fungus Cellar test indicated differences in decay rates between birch and pine and also between soils. The decay rate observed for pine stakes was generally lower than birch in both soils. The decay rate was greatly accelerated in a Michigan soil with birch and pine over that observed in a Florida soil. Soil type had less impact on the primary decay present in the stakes. Soft rot was the primary decay associated with treated wood in both soils, while soft rot, basidiomycete, or combinations of the two were frequently found in untreated wood. The range of weight loss vs visual rating relationship was similar between wood species, treatment, and soil type. Weight losses tended to "overlap" the visual ratings regardless of the decay type.
P A McKaig


Laboratory studies of CCA-C-leaching: influence of wood and soil properties on extent of arsenic and copper depletion
2002 - IRG/WP 02-50186
The extent which a wood preservative leaches is important for efficacy studies and environmental concerns. However, little information exists on the effect soil properties have on leaching. This study investigated leaching of stakelets which had been cut from five different southern yellow pine (SYP) sapwood boards then treated with CCA-C to a target retention of 6.4 kgm-3 (0.4 pcf). All stakelets were leached for 12 weeks by a common laboratory method in five different soils or water, with five replicate stakelets per board/soil. The physical and chemical properties of the five different soils were determined and the average leaching of the individual components of CCA was correlated with the various soil properties. Unfortunately, migration of a soil component (likely iron) into the stakelets from at least one of the five soils interfered with Cr determination by X-ray fluorescence; consequently, Cr depletion was not studied. Stakelets cut from one board tended to have lower Cu and As losses than the average of the other four boards for all five soils and water, and stakelets from another board tended to have higher Cu losses. Stakelets from all five boards had similar initial Cu and As levels, suggesting that the board effect was not due to differences in initial retentions. Cu loss was approximately equal to or greater than As loss for stakelets exposed to all five soils, but for wood leached in water the As loss was about twice the Cu loss. The soil property which was most statistically correlated to Cu loss was % Base Saturation (r2 of 77%), with Soil Acidity (pH) also important as a single predictor, and the Cr and Cu Soil Contents important as secondary predictors. The relationship between % Base Saturation (or Soil Acidity) and % Cu leached was not linear, however. A negative correlation was observed between Soil Cu Content and the metal leached from wood. The best factor to predict As loss was the Soil Cu Content, with Exchangeable K and % Silt also contributing to give an overall r2 of 72.3%. The % Organic Matter and the Soil As Content were also important as secondary predictors. We conclude that depletion of CCA is extremely complex and that Cu and As depletion appears to be influenced differently by the soil properties. Furthermore, extent of leaching can vary between different wood samples of the same species and even samples cut from the same board; thus, leaching data are not precise. Recommendations are given for a standard laboratory method for ground-contact leaching.
D Crawford, R F Fox, D P Kamden, S T Lebow, D D Nicholas, D Pettry, T Schultz, L Sites, R J Ziobro


Water repellency of wood treated with alkylammonium compounds and chromated copper arsenate
2000 - IRG/WP 00-30231
The comparative water sorption properties of southern pine treated with CCA and several alkylammonium compounds was evaluated for freshly treated wood and for wood after exposure in a fungus cellar. It was found that CCA imparts considerable water repellency to wood which is reduced somewhat after exposure to wet soil. With the exception of a long chain (C20 -C22) compound, the alkylammonium compound treated wood exhibited an increased water sorption rate and also exhibited increased total swelling.
D D Nicholas, A Kabir, A D Williams, A F Preston


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