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Decay resistance of a commercial pistachio twig-plastic composite
2011 - IRG/WP 11-40553
In this research, the decay resistance of commercial extruded pistachio twig flour-plastic composite was investigated against the white-rot fungi Trametes versicolor and the brown-rot fungus Coniophora puteana. The composite specimens containing 60% pistachio twig flour were exposed to a decay test according to modified ASTM standard for 3 months. The results showed that the composite could be decayed by the fungi. The weight loss of the composite due to decay by C.puteana was noticeably higher than that for T.versicolor. By employing scanning electron microscopic (SEM) studies, cracks and voids in the control (unexposed samples), and hyphae penetration in the sample decayed by C.puteana were shown.
M R M Farahani, M Safarzadeh


Effect ofNano-Copper Oxide on Decay Resistance of Pistachio Twig-Plastic Composite
2019 - IRG/WP 19-30750
The goal of our study was to investigate the decay resistance of pistachio twig-plastic composite treated with nano-copper oxide against the white rot fungus Trametes versicoloer and the brown rot fungus Coniophora puteana. For this purpose, wood–polypropylene composites (WPCs) containing different loadings of nano-copper oxide, namely 0, 1, 2 and 3 percent (W/W), were made from pistachio (Pistacia vera L) twigs using a batch method. After being subjected to five cycles of boiling/oven-drying, the WPCs, were exposed to the white rot fungus Trametes versicolor (Linneaus) Lloyed (CTB 863 A) and the brown rot fungus Coniophora puteana ( Schumacher ex fries) Karesten (BAM Ebw. 15) in a soil block decay test for three months in accordance with a modified ASTM D1413 test standard. Scanning electron microscopy (SEM) was used to examine the WPCs exposed to decay and to study the distribution of nano-copper oxide in the composite. No clear evidence of the sever agglomeration of nano-copper oxide at a loading of 3% (W/W) was obtained using SEM. The results showed that nano-copper oxide enhanced the decay resistance of the composite against the fungi so that the weight loss (WL) due to decay decreased as the loading increased. Noticeable differences in WL due to decay were observed between the fungi for all the composites. The WLs due to decay by the brown rot fungus were higher than those by the white rot fungus. Copper oxalate crystals were detected in the composite containing 3% nano-copper exposed to C. puteana but they were seemed to have been produced in low amounts.
M R M Farahani,S Pourabdollah


Termite resistance of wood-plastic composites made with acetylated wood flour, coupling agent or zinc borate
2018 - IRG/WP 18-10917
There is little published scientific literature on the laboratory or field testing of wood-plastic composites (WPC) against termite attack. Therefore, the objective of this research was to investigate termite resistance (both laboratory and field) of 5 different extruded WPC blends of 50% western pine wood flour (WF) and high-density polyethylene (HDPE), and untreated pine solid wood. The study included two unmodified control WPC blends (one with cut surfaces and one with plastic rich surfaces); one blend with 3% coupling agent (maleated polyethylene, MAPE); one blend with acetylated WF; and one blend with 1% ZB. These 3 modifications/treatments were chosen because (1) coupling agents are known to promote bonding between the plastic and unmodified wood fibers when added to WPCs; (2) acetylating the wood esterifies the hydroxyl groups, making the wood more hydrophobic, dimensionally stable, and biologically durable; and (3) ZB is a known fungicide and insecticide used in some commercial WPC formulations. All WPC blends tested performed well (0.1% - 0.7% weight loss; 66% – 71% termite mortality) in the 10 week dry-wood laboratory termite test compared to the untreated solid wood (9.1% weight loss; 33.8% mortality.) Field exposure ratings are on a scale from 0 (complete failure) to 10 (sound, one to 2 small nibbles should be permitted.) After 30 months field exposure to Macrotermes gilvus Hagen in Bogor, Indonesia the acetylated WPCs performed the best with ratings of all 10s and only 0.8% weight loss, followed by the 1% ZB blend with ratings of all 9s and 3.9% weight loss. The coupling agent blend had ratings of all 8s and 13.6% weight loss, while the unmodified WPC controls had ratings of 7 and from 11.3-22.6% weight loss. The solid wood was completely destroyed with 100% weight loss and 0 rating.
R E Ibach, Y S Hadi, C M Clemons, S Yusuf


Durability of Wood Plastic Composites Relative to Natural Weathering and Preservative Treatment With Zinc Borate
2005 - IRG/WP 05-40316
Wood-Plastic Composites (WPCs) used for decking have experienced dramatic increases in North America, averaging 25% growth per annum since 1998. A key factor contributing to this growth has been the successfully communicated message that they are "virtually maintenance free". The common perception being that the wood fiber is completely encapsulated by the thermoplastic resin, minimizing the potential for moisture absorption and inhibiting attack by wood destroying organisms. Recent publications, however, have raised concerns about the durability of WPCs. These studies showed that wood particles close to the surface of WPC products can attain moisture levels high enough to facilitate the onset of decay. Other experiments have shown that preconditioning this material through accelerated laboratory weathering (QUV) or natural exterior exposure to the elements, yielded significant increases in moisture uptake relative to the unexposed samples. The ability of these materials to absorb moisture has been identified as a significant factor in evaluating decay susceptibility in these laboratory tests. We examined moisture uptake in large sized (low surface to volume ratio) and smaller cut (high surface to volume ratio) WPC samples and found a much greater and rapid water uptake in the smaller samples. A soil block decay test with commercially produced unweathered WPC’s resulted in weight losses of between 10-20% (20-40% wood component) in as little as four months time. Effects of exterior weathering on moisture uptake showed increased moisture in samples taken from WPC boards in the field at various locations for 1 to 2 years. A soil block decay test with unweathered and naturally weathered WPCs showed significantly high weight loses in samples that had been in an outdoor exposure in Valencia, Ca for 2 years. Samples from the same exposure test that had been treated with 1.0 or 2.0 % zinc borate showed almost no weight loss.
M E Mankowski, F M Ascherl, M J Manning


Wood-Plastic Composites and the Durability Dilemma: Observations from the Field
2006 - IRG/WP 06-40351
Wood-Plastic Composites (WPCs) used for decking, window & door moldings have experienced dramatic growth in North America over the last several years, with annual production increasing at rates greater than 20% per annum since 1998. A key factor contributing to this growth has been the successfully communicated message that they are "virtually maintenance free". The common perception being that the wood fiber is encapsulated by the thermoplastic resin, minimizing the potential for moisture absorption and inhibiting attack by wood destroying organisms. A number of recent publications have raised concerns about the long-term durability of WPCs – in particular, when used in unprotected, above-ground applications. The fundamental question is whether or not the % Moisture Content (%MC) of the wood component can achieve the minimum level necessary to support fungal decay. Laboratory tests utilized by the WPC industry suggest this is not the case and yield values less than 10%MC - well below the accepted minimum threshold of 25% necessary to initiate and support fungal decay. This paper will describe work which evaluates the %MC of the wood component in WPC samples exposed in various field sites with different climatic Scheffer indices. These field results yield a dramatically different picture and show that the outer portion of the WPC surface can achieve %MC levels in the wood component which are in excess of the 25% threshold. Both macro and microscopic evaluations of untreated WPC material revealed evidence of fungal decay. The use of a preservative treatment such as zinc borate to protect against fungal decay will also be discussed.
M J Manning, F M Ascherl, M E Mankowski


Wood plastic composites from modified wood. Part 3. Durability of WPCs with bioderived matrix
2008 - IRG/WP 08-40423
The decay resistance of fully bio-derived wood plastic composites, WPCs, was tested in both laboratory and field tests. The laboratory tests were performed according to modified versions of AWPA E10 (soil-block test) and ENV 807 (tests in three un-sterile soils) and the field tests according to EN 252 (stakes in ground) and EN 275 (resistance to marine borers). The WPC materials for laboratory tests were injection molded test specimens with 50% modified wood particles and 50% cellulose ester (CAP) or poly-lactic acid (PLA) content. The field test specimens were taken from larger extruded decking board profiles with 60% wood content and 40% CAP. 60/40-mix (wt/wt) for CAP corresponds to the same volumetric composition as 70/30-mix (wt/wt) with polypropylene as matrix that was presented in Part 1 and 2. In all laboratory tests the control WPCs performed much better than the pine sapwood control blocks. The WPCs from modified wood performed better than the control WPC and WPCs from acetylated wood performed best with no detectable decay whatsoever. In the field stake test, the WPC from unmodified wood were slightly decayed whereas the WPCs from modified wood were sound. In the marine field test the WPC from unmodified wood were severely attacked by shipworm (Teredo navalis), whereas the WPCs from modified wood were sound.
M Westin, P Larsson Brelid, B K Segerholm, M Van den Oever


Progress in Fire-Retardant Research on Wood and Wood-Based Composites: a China Perspective
2009 - IRG/WP 09-40476
The fire retardant research on wood and wood-based composites, which was carried out in China in the past two decades, was reviewed with 55 references. While many kinds of fire retardants for wood and wood-based composites have been studied, the mainstream is still the compound or the mixture containing phosphorus, nitrogen and boron elements, which can be used in the form of water solution in the impregnation of solid wood. The fire-retardant treatment methods for wood panels are either pretreatment of veneers, fibres, particles and strands before hot pressing, or the impregnation of waterproof panels by fire-retardant solution. Though attempts have been done in lab to mix fire retardants with the glue, it has proved to be very difficult to spray glue with effective amount of fire retardants smoothly in the real manufacturing of fire-retardant panels. Fire retarding mechanism of phosphorus-nitrogen-boron fire retardants have been investigated systematically. The results indicated that for a proper fire-retardant formulation phosphorus-nitrogen compounds and boron compound are highly synergistic, that the catalytic charring effect of a fire retardant on wood is a key factor to its fire-retardant efficiency, and that a chemical fire-retardant mechanism for boric acid was proposed. The fire-retardant research on wood plastic composites has attracted more attention in recent years, however, most results are basically preliminary because of the difficulty for choosing or setting up a suitable fire retardant system that is effective to both of wood and plastics. Research on smoke suppression of wood was also discussed which was even more preliminary and innovative efforts are needed.
Wang Qingwen, Wang Fengqiang, Hu Yunchu, Li Jian


Lignin blocking effects on weathering process of wood plastic composites
2010 - IRG/WP 10-40529
The weathering of wood–plastic composites (WPC) causes discoloration which affects their aesthetic aspects. It has been proved that these discolorations are due to lignin degradation. Effects of blocking the susceptible structure of lignin assessed by chemical treatment such as acetylation and methylation are reported in this study. Surface chemical change of wood plastic composite (WPC) formulations based on high density polyethylene (HDPE) were monitored by means of ATR FT-IR spectroscopy and colorimetry. According to the standard ASTM 2565, samples were placed in Atlas Xenon apparatus for 250 hrs and 2000 hrs. The results have shown that methylation and acetylation can photostabilize lignin in short period of times. ATR FT-IR spectra shown that, in long term, none of the treatments could protect lignin degradation, within wood flour. Methylation limited the depth of penetration of weathering and these samples have more lignin content compared to control samples.
P Darabi, A Naghi karimi, S Ahmade Mirshokraie, M-F Thévenon


Moisture and Fungal Durability of Wood-Plastic Composites Made With Chemically Modified and Treated Wood Flour
2013 - IRG/WP 13-40648
Evaluating the fungal durability of wood-plastic composites (WPCs) is complicated by the influence of slow moisture sorption. Recently, the American Wood Protection Association (AWPA) Standard Method E10, Testing Wood Preservatives by Laboratory Soil-Block Cultures, was modified to incorporate not only solid wood, but also wood-based composites and WPCs. To simulate long term WPC performance, conditioning of the specimens is now required prior to fungal exposure to increase the moisture content of the specimens. The moisture and fungal durability, as well as the mechanical properties, of two different WPCs were investigated in the laboratory following this new AWPA E10-12 Standard. Wood flour was modified with acetic anhydride and then extruded with high density polyethylene (HDPE). Wood flour was treated with an isothiazolone-based solution and then injected molded with polypropylene (PP). WPCs were conditioned by water soaking either 2 weeks at 22 ˚C or 5 days at 70 ˚C. Weight and moisture content of the WPCs were monitored. Results showed that the acetylation decreased the moisture sorption of the WPCs and showed no mass losses due to decay. The WPC with an isothiazolone-based solution did not show any mass losses due to fungal decay.
B K Segerholm, R E Ibach


Conclusions and Summary Report on an Environmental Life Cycle Assessment of ACQ-Treated Lumber Decking with Comparisons to Wood Plastic Composite Decking
2013 - IRG/WP 13-50295
The Treated Wood Council has completed a quantitative evaluation of the environmental impacts associated with the national production, use, and disposition of ACQ (alkaline copper quaternary)-treated lumber decking and wood plastic composite decking using life cycle assessment (LCA) methodologies and following ISO 14044 standards. The results for treated wood decking are significant. • Less Energy & Resource Use: Treated wood decking requires less total energy, less fossil fuel, and less water than wood plastic composite decking. • Lower Environmental Impacts: Treated wood decking has lower environmental impacts in comparison to wood plastic composite decking in all five of the impact indicator categories assessed: anthropogenic greenhouse gas, acid rain, smog potential, ecotoxicity, and eutrophication-causing emissions. • Less Fossil Fuel Use: The fossil fuel footprint of a treated wood deck is equivalent to driving a car 38 miles/year. In comparison, the fossil fuel footprint of a wood plastic composite deck is equivalent to driving a car 540 miles/year. • Recoverable Energy: The carbon embodied in wood makes out-of-service wood products excellent candidates for energy recovery. Treated wood can be used in cogeneration facilities or synthetic fuel manufacturing facilities as a non-fossil fuel source. Impact indicator values for the cradle-to-grave life cycle of ACQ-treated lumber were normalized to one (1.0), with wood plastic decking impact indicator values being a multiple of one (if larger) or a fraction of one (if smaller).
AquAeTer, Inc.


Decay resistance of wood-plastic composites reinforced with extracted or delignified wood flour
2014 - IRG/WP 14-40655
The moisture and decay resistance of wood-plastic composites (WPCs) reinforced with extracted or delignified wood flour (WF) was investigated. Three different extractions were preformed: toluene/ethanol (TE), acetone/water (AW), and hot water (HW). Delignification (DL) was performed using a sodium chlorite/acetic acid solution. All WPCs specimens were made with 50% by weight HDPE and WF, first compounded using extrusion followed by injection molding. After preconditioning in water at 70 °C for 5 days, the specimens were exposed for 12 weeks to the brown-rot fungus, Gloeophyllum trabeum in the AWPA D1413 standard soil block test. The WPC made with untreated wood flour had the highest overall weight loss (24.9 ±3.6%), followed by the HW (22.3 ±4.6%) and DL (16.4 ±3%). The TE (7.8 ±0.8%) and AW (7.7 ±2.3%) had the lowest weight losses. WPC moisture content was monitored before and after decay. Cracking was observed in some blends after the preconditioning, which may explain the differences in weight loss.
R E Ibach, Yao Chen, N M Stark, M A Tshabalala, Yongming Fan, Jianmin Gao


Modern Instrumental Methods to Investigate the Mechanism of Biological Decay in Wood Plastic Composites
2014 - IRG/WP 14-40674
Various instrumental techniques were used to study the fungal decay process in wood plastic composite (WPC) boards. Commercial boards exposed near Hilo, Hawaii (HI) for eight years in both sun and shadow locations were inspected and tested periodically. After eight years of exposure, both boards were evaluated using magnetic resonance imaging (MRI), while a selected area of the board exposed in shadow was additionally tested using microscopy and micro x-ray computed tomography (CT). Experimental boards exposed to either exterior conditions in Vancouver, British Columbia (BC) or a laboratory decay process were used for verification of MRI and CT results obtained from the commercial board. MRI detected the presence of free water and its distribution in the exposed commercial board samples tested. Fibre saturation in the experimental board was found to be about 22%, in comparison to 27 – 30% present in most wood species. There was good correlation between the detection of free water by MRI and by destructive testing. Reconstructed volumes from CT scans of the tested boards allowed for the WPC microstructure to be observed in various planes of view and for void analysis of the material to be conducted. A significantly higher average percentage volume of voids was detected in the exposed sample compared to its reference unexposed counterpart. CT scans and subsequent void analysis of the experimental soil block culture test samples of known weight loss in wood demonstrated this technique to be reasonably accurate in the detection of voids created due to biological decay. No obvious relationship was established between the presence of free water detected by MRI and the average volume of voids detected by CT. Scanning electron microscopy (SEM) confirmed the presence of fungal mycelia in the exposed commercial board cross-section imaged by both MRI and CT. It was confirmed that both MRI and micro CT could be used for non-destructive evaluations of WPC materials, including their decay process. This work also found that many different decay fungi species could colonize and internally damage WPC, and that fungal decay in WPC seems to be a self-propagating process requiring an initiation time period where no obvious decay damage is observed.
G Sun, R Ibach, M Gnatowski, J Glaeser, M Leung, J Haight


Durability of a willow/plastic composite mat
2016 - IRG/WP 16-20592
Developing uses for wood wastes could enhance utilization of low value renewable materials while creating opportunities for rural development. Small diameter willow stems have little use in China, but they could be combined with high density polyethylene to create wood plastic composite mats for decorative applications. These mats could be used in exterior, above ground exposures, but would still require some level of resistance to decay and mold. The potential for using desert willow (Salix psammphila) from Inner Mongolia as the supporting material for plastic composite matting was evaluated in decay and mold tests. The resulting mats were highly susceptible to attack by decay fungi, and exhibited susceptibility to mold especially where the willow was exposed on the surface. The results suggest that these products have some potential for applications where they are more protected from moisture but would need supplemental treatment in wetter exposures.
Li Yan, Haiyan Duan, Beizhan Quan, J Cappellazzi, J J Morrell


Properties of Wood Plastic Composites Made of Recycled HDPE and Remediated Wood Flour from CCA/CCB Treated Wood Removed from Service
2016 - IRG/WP 16-40747
Chromated copper arsenate (CCA) and copper, chromium and boron (CCB) have been widely used in pressure treated wood as a heavy duty preservative to protect wood against insects and fungi for more than 60 years. Although many attempts have been done to solve the problems related to out-service treated wood, the problem still remains. Only a few studies were done to utilize the out-of service treated wood materials to produce WPCs. The objective of this study was to determine the mechanical, physical and thermal properties of WPCs produced from remediated CCA/CCB and CCA/CCB wood flour without remediation. The results showed that The water absorption values for the WPCs produced from remediated CCA or CCB wood flour were higher than that of CCA or CCB wood sawdust; however, lower than the WPCs produced from virgin pine flour. The mechanical properties of WPCs produced from either CCA or CCB wood flour were higher than that of produced from virgin pine wood floor. Thermal properties of WPCs were also determined.
E D Gezer, S Akbaş, M Tufan, A Temiz


Fungal resistance and accelerated weathering of Wood-Plastic composites reinforced with Maritime pine wood flour
2016 - IRG/WP 16-40750
This study evaluates the durability of wood-polymer composites (WPCs) elaborated for use in cladding application from recycled polypropylene (rPP) and wood flour. Local Maritime pine wood flour derived from regional sawmills was used in the study to reduce the environmental impact associated with transport. Different wood-plastic ratios with and without UV stabilizers and biocide were tested. One biocide and two UV stabilizers were tested and their impact on the performances of the elaborated composites was assessed by artificial weathering and fungal decay tests. Results showed that formulation with biocide exhibited low masse losses. Compared with the formulations without UV stabilizers, accelerated weathering resulted in discoloration (E) and slight reduction of the maximum strain, which was enhanced by the addition of 1 wt% UV stabilizers to WPCs formulations. The study showed that the performances of WPCs elaborated from maritime pine wood flour and recycled PP could significantly be improved by using biocide and UV stabilizers.
M Jebrane, T Fournier, N-E El Bounia, F Charrier-El Bouhtoury


Long-term field exposure of wood-plastic composites processed on a commercial-size extruder
2020 - IRG/WP 20-40894
Wood-plastic composites (WPC) contain wood fiber (or flour), thermoplastics and additives and are exposed to UV light, moisture, and biological deterioration in outdoor installations. Accelerated laboratory tests can help to predict the durability of WPCs, but long term evaluations are needed to validate these results. Field exposed above-ground WPC deck boards (30.5 x 139.7 x 609.6 mm) and in-ground (19 x 19 x 457 mm) stakes were visually evaluated near Saucier, Mississippi and Madison, Wisconsin over 17 years. Four blends were extruded on commercial-scale equipment containing additives including colorant, light stabilizers, lubricant, and the fungicide zinc borate (ZnB). There are some difficulties evaluating the WPC materials compared to solid wood: in-ground stakes snap quite easily when removing them for inspection and decay is more difficult to determine because the WPC does not become soft. Differences in deterioration were seen between each test site: the in-ground deterioration was more severe in Mississippi and the above-ground deterioration was more severe in Wisconsin. The ZnB fungicide provided some decay protection in-ground even at the low level of 1%, and the UV stabilizer package (including colorant) slowed the color change compared to the WPC control above-ground. The blend including both ZnB and UV package provided both decay and UV protection, but mold and stain are still an issue for above-ground. The in-ground results are analogous to the short-term accelerated laboratory evaluations.
R E Ibach, C M Clemmons, N M Stark


Soil blocks versus field test for evaluating and standardizing wood preservatives: A commercial view
1994 - IRG/WP 94-20024
On the basis of technical considerations, experience, costs and applicability, the author concludes that the soil block test and other laboratory tests have little meaning in a wood preservative standardization process and almost no merit in the commercialization of a wood preservative system. Field tests at sites known to be aggressive to preservative treated wood are strongly recommended.
W S McNamara


Contribution to the testing of wood based board material
1982 - IRG/WP 2176
R G Lea


Improvement of liquid penetration of wood by precompression under appropriate conditions and recovery process
1993 - IRG/WP 93-40014
A new system for enhancing the penetration of liquid into wood using a precompression treatment was designed, and the effects of compressive deformation and recovery on liquid uptake were evaluated. Precompression of up to 60% under appropriate moisture and heat conditions effectively increased the penetration of liquid into refractory wood samples of practical sizes without producing any strength reduction. Water-saturated wood was compressed perpendicularly to the grain at temperature of 30 to 80°C, and two types of pretreated wood were prepared; i.e., set-recovered wood in which loading was released immediately after precompression, and preset-fixed wood which was dried under the influence of a decompressive force. The amount of liquid taken up by set-recovered wood was 2-3 times that taken up by untreated wood. When preset-fixed wood was dipped in liquid and the deforming force was released, liquid penetration was more than 25 times that seen in untreated softwood heartwood. Liquid effectively penetrated even long samples when pressure impregnation was applied to precompressed and preset-fixed wood. No significant reduction of strength was observed for treated wood except for that which had been precompressed up to 60%. Fracture of pit membranes during compression with little damage to unpitted cell-walls and an elastic recovery process were believed to improve liquid penetration with negligible compression defects.
I Iida, Y Imamura


A study of salt imbalances observed in recycled copper/chrome/arsenic preservative solutions in commercial practice
1987 - IRG/WP 3461
The study reported monitored tank solutions, sludge and other by-products using a standard CCA solution, when recycled. This recycling of the CCA solution is quite usual in between any commercial treatment schedules. Salt imbalances were observed and the possible reasons for such phenomena were studied. The paper discusses the procedure followed, the method of sampling the liquid after the charge and the analysis, to arrive finally at an aggregation and conclusion from the data.
V R Sonti, S Sonti, B Chatterjee


Natural durability of some commercial timbers of Sarawak, Malaysia in tropical marine environment
2005 - IRG/WP 05-10561
The abundant supply of timber resources in Sarawak makes timber an ideal choice to be used for marine construction. The natural durability of the main commercial timber species of Sarawak in ground contact is well established but the same is not available for marine environment. This study was conducted to assess the natural durability of 28 commercial timber species in tropical marine environment. Timber specimens measuring 30mm x 100mm x 300mm each suspended in metal cages were exposed at two sites to marine borer attack for a period of 12 years. Durability was assessed at six-monthly interval. The borer species found at the test sites were identified including one new borer species encountered. In addition, water quality parameters encompassing current speed, temperature, dissolved oxygen, salinity, turbidity and pH were monitored during the period. The results show that none of the species was durable with mean durability ranging from <0.5 – 3.0 years. Even Belian (Eusideroxylon zwageri) dubbed as the “iron wood of Borneo” and being the most durable timber species in Sarawak especially in ground contact and siliceous timber such as Kembang semangkok (Scaphium macropodum) has a mean durability of 3.0 and 1.2 years in marine environment, respectively. The majority of the species failed within six months. The specimens were destroyed by a combined action of teredine borers and pholad.
K Jenang, Wang Choon Ling


Reworded resolution
1976 - IRG/WP 145
New evidence has demonstrated that certain timber species are unexpectedly difficult to protect against biological degradation by the use of known preservation systems. Several of these timber species are expected to become of wide commercial use in the future. The issues raised are of such fundamental importance and require so intensive basic research that official bodies should be encouraged to devote funds for further study.
B Henningsson


Information from COIPM Wood Group
1985 - IRG/WP 4120
During the last COIPM Meeting (which took place in Athens, Greece in September 1984) the Wood Group met and discussed the co-operative work &apos;Durability in sea-water of wood with plastic wraps and wood treated with polymere&apos;.
A Gambetta


Plastic-coated marine piling in Los Angeles Harbour
1984 - IRG/WP 4105
G Horeczko


Copper binding capacity of modified wood flour
1992 - IRG/WP 92-3709
Wood flour was modified by reaction with oxidising agents and CCA preservative. The copper chromium and arsenic were removed from the CCA treated wood flour by an acid leaching procedure. The modified wood flours were allowed to react with copper acetate solution and the level of copper fixation achieved was determined. The modified wood flours had greater affinity for copper ions present in solution than unmodified wood flour.
N C Milowych, W B Banks, J A Cornfield


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