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The decay resistance of chemically modified aspen composites to the white rot fungus Coriolus versicolor (L.) Quelet
1998 - IRG/WP 98-40122
Chemical modification of Aspen wood (Populus tremula L.) in the form of solid wood, veneers and sawdust was undertaken by a two step procedure consisting of esterification with maleic anhydride (MA) and subsequent oligoesterification with MA and glycidyl methacrylate (GMA) or allyl glycidyl ether (AGE). Modified wood was thermoplastic and was thermally formed by hot-pressing to produce veneer or solid wood samples with smooth glossy surfaces, while plastic-like wafers were obtained by hotpressing modified sawdust. Chemical modification alone was shown to enhance the biological resistance of Aspen to decay by Coriolus versicolor. In addition, hot-pressing enhanced decay resistance of both unmodified wood and esterified wood veneer samples, although no improvement was found by hot pressing oligoesterified wood. The most effective treatment for the improvement of decay resistance was chemical modification of the sawdust in conjunction with hot-pressing. A microscopic examination of chemically modified and control samples following exposure to the fungus showed more extensive colonisation and decay in untreated, unpressed samples.
M C Timar, A J Pitman, M D Mihai


About the water and biological resistance of some new chemically modified wood composites
1997 - IRG/WP 97-40077
As well known, wood represents a valuable natural composite material with a very large utilisation as solid wood or in wood based composite materials. Its qualities but also its defects as the dimensional instability, the susceptibility to biological attack, the anisotropy, are due to its complex structure. Research has demonstrated that the chemical modification of wood, meaning the involving of its main chemical components through their reactive alcoholic hydroxyl groups in chemical reactions with different chemical reagents, can be a new way to ameliorate the wood or wood composites but also to obtain new wood based materials. The chemical thermoplasticization of wood, studied theoretically and experimentally by the Japanese researchers as Matsuda, Mori, Morita, Nakano, Shiraishi, Ueda seems to be a very interesting possibility. The paper presents the results of our experiments concerning the chemical thermoplasticization of wood through oligoesterification and the obtaining and characterisation of some products based on this type of chemically modified wood. In fact the main goals of this stage of the researches were: - the obtaining and characterisation of the thermoplastic wood; - the study of the thermoformation possibilities for the thermally flowable material obtained as sawdust; - the evaluation of the possibilities to carry out this chemical modification process as a surface treatment for solid wood; - the evaluation of the water and biological resistance for the obtained products.
M C Timar, M D Mihai, G Baciu


Termite field test results of preservative treated and modified woods in Kumamoto, Japan
2001 - IRG/WP 01-30275
Various preservative treated or modified wood stakes other than CCA, were buried in the soil, maximum for six years in Kumamoto, south west side of Japan. In this area, two main termite species, Coptotermes formosanus and Reticulitermes speratus, are distributed. After two years in field, untreated sapwood of sugi (Cryptomeria japonica) were observed severe attacks by termites, but the preservative treated stakes were observed no significant attacks by termites. After six years, treated stakes with preservatives not included copper, like DDAC and zinc-naphthenate, were observed slight or moderate attacks by termites. Otherwise, in the case of treated stakes with preservatives included copper, like ACQ, copper naphthenate and Tanalith CuAz, no significant attacks by termites were observed. Few samples of chemically modified wood or LVL were observed slight attacks by termites for four years.
K Suzuki


Results on field stake tests against termite – Maximum for 8 years examination at Kumamoto in Japan
2003 - IRG/WP 03-10463
Various preservative treated or modified wood and charcoal painting stakes were tested in field, maximum for eight years in Kumamoto, distributed two main termite species, Coptotermes formosanus and Reticulitermes speratus. After two years in field, untreated sapwood of sugi (Cryptomeria japonica) were observed severe attacks by termites, but the preservative treated stakes were observed no significant attacks by termites. After eight years experiment, treated stakes with preservatives not included copper, like DDAC and zinc-naphthenate, were observed slight or moderate attacks by termites. Otherwise, in the case of treated stakes with preservatives included copper, like ACQ, copper naphthenate and Tanalith CuAz, no significant attacks by termites were observed. Few samples of chemically modified wood or LVL were observed slight attacks by termites for seven years.
K Suzuki


The Effect on Biological and Moisture Resistance of Epichlorohydrin Chemically Modified Wood
2002 - IRG/WP 02-40224
Southern pine solid wood and fiber were chemically modified with epichlorohydrin to help in understanding the role of moisture in the mechanism of biological effectiveness of chemically modified wood. The solid wood had weight gains from 11% to 34%, while the fiber had weight gains from 9% to 75%. After modification, part of the specimens were water leached for 2 weeks or extracted for 2 hours with a toluene:ethanol (2:1) solution. The equilibrium moisture content (EMC) at 30%, 65%, and 90% relative humidity (RH) and 27 °C was determined on all specimens. Laboratory soil block decay testing using the brown-rot fungus Gloeophyllum trabeum was performed and weight loss calculated. Results show that epichlorohydrin modified specimens did not lower the EMC significantly, yet there was biological effectiveness at 31% weight gain for the solid wood and 60% weight gain for the fiber. This indicates that the mechanism of efficacy may be due to substrate modification rather than moisture exclusion. Energy dispersive x-ray analysis (EDXA) was performed locating the chlorine throughout the wood cell wall.
R E Ibach, B-G Lee


Chemically modified tannin and tannin-copper complexes as preservatives for wood
2001 - IRG/WP 01-30271
The efficacy of Mimosa tannin, chemically modified tannin, and tannin-copper complexes as wood preservatives was studied. When the tannin-ammonia-CuCl2 solutions were impregnated into wood specimens in a one-step procedure, a large quantity of the tannin-copper complex was fixed in the specimens. Little of the complex was leached from specimens by a weathering treatment, and these specimens showed satisfactory decay resistance in a basidiomycete laboratory test according to the Japanese Industrial Standard (JIS) K 1571-1998. Only the tannin-treated wood had a retention of agent after treatment, in increasing order from untreated tannin (MT), resorcinolated tannin (RMT) and catecholated tannin (CMT). When RMT or CMT was mixed with ammonia¡copper, the wood retained twice as much of these solutions as the MT-ammonia-copper solution. The solutions penetrated 2~13mm from the tangential sections of the logs. Presumably, chemical modification increased the degree of retention by altering the structure of the tannin and increasing its hydrophilic properties. The degree of retention of RMT-NH3-Cu and CMT-NH3-Cu in logs with cross-sections ranged from 268 kg/m3 to 326 kg/m3. Wood decay by F. palustris was markedly suppressed by processing wood with agents made by mixing chemically modified tannins with ammonia and cupric chloride. When wood powder was treated with these agents, mycelial growth and generated protein increased to some extent. The preservative effects of the chemically modified tannins (RMT and CMT) or compound agents composed of the tannins and ammonia¡copper were considered to be due to inhibition of the activities of mannase and Cx-cellulase. In the culture medium which treated wood powder was put in with these agents, drop of pH by oxalic acid, which Fomitopsis palustris produces, is not generated. The potency of the effect was thought to be due to chelation of copper, an essential trace element for wood decay by F. palustris, by the tannin, and/or neutralization or suppression of oxalic acid production by ammonia-copper. Also, these active ingredients hindered eating-damage of wood by the termites. However, the mortality of the termites during the eating-damage test (over 21d) did not reach 100% for all active ingredients. The fact that living termites were still present suggests that tannin-ammonia-copper is not perfect for destroying termites.
H Yamaguchi


Study of UV resistance and natural weathering of coatings on chemically modified wood
2013 - IRG/WP 13-40629
In this study, UV resistance and weathering performance of rubberwood (Hevea brasiliensis) and radiata pine (Pinus radiata) modified with benzoyl chloride and acetic anhydride was studied. Performance of polyurethane based wood coatings on modified wood was also evaluated. Unmodified and chemically modified specimens were exposed to accelerated and natural weathering. Modified and unmodified wood specimens were coated with commercially available polyurethane based transparent and opaque finishes and exposed to natural weathering for a period of 2 years. Physical and chemical deteriorations on uncoated / coated wood panels due to weathering were periodically monitored. Analysis of colour changes and chemical deteriorations of weathered specimens showed rapid discolouration and lignin degradation on unmodified wood surface exposed to weathering. Modified wood showed resistance to weathering and was partially effective in inducing UV resistance as compared to unmodified wood. Results clearly indicate that performance of coating can be significantly improved by chemically modifying wood substrate with benzoyl chloride. Benzoylation of wood polymers improved coatings adhesion and enhanced life of paints by 3-4 times. The performance of opaque coating was better than transparent coating, presumably due to photodegradation of wood substrate in transparent coating.
K K Pandey, K Srinivas


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


FTIR-ATR monitoring of chemical changes of thermo-chemically modified beech wood degraded by brown-rot fungus
2018 - IRG/WP 18-40823
Wood chemical modification with lactic acid oligomers (OLA) has been reported to confer promising properties for wood outdoors applications. To better understand the lactic acid interaction with wood, chemical changes following biological degradation have been characterized with a battery of tests. Fourier transform infrared (FTIR) spectroscopy has been proved to be a valuable tool for studying fungal decay and chemical changes of degraded beech wood have been already investigated. In this study, changes in modified wood chemistry following decay by brow-rot fungus were assessed by FTIR spectroscopy. Wood specimens of beech (Fagus sylvatica L.) were modified by a thermo-chemical treatment process. Oligomer systems based on lactic acid, were impregnated in oven-dried wood and polymerised in situ by heat treatment according to a treatment process reported by Grosse et al. (2016). Treated and untreated specimens were tested according to the guidelines of EN 113 standard: after water leaching (EN84), samples were exposed to Coniophora puteana for 16 weeks. Decay was assessed through weight loss: values for treated samples were in the range of 2.69% to 3.76% for modified wood and 29.7% for native beech. The ratios of the areas of the lignin/carbohydrates FTIR peaks were determined before and after exposure. Lignin, carbohydrates and cured OLA associated bands relative intensities were used to assess wood degradation. Analyse of the degradation patterns of modified wood, in comparison with unmodified wood, shows the effect of treatment on fungal mode of action regarding the attack selectivity on modified wood components (lignin, carbohydrates and OLA).
C Grosse, M Noël, M-F Thevenon, P Gérardin


Study on the ability of wood-destroying fungi to grow through chemically modified wood
2019 - IRG/WP 19-40858
Over the last decades, chemical wood modification technologies were developed to increase the resistance against attack by wood-destroying organisms without using biocides. Most of those technologies are based on an impregnation step initially. In most treated wood products, mainly by using solid wood in thicker dimensions as in posts, poles, sleepers, deckings etc. it is known that wood impregnation fluids are not distributed throughout the whole wood cross diameter, but just form a protected zone (‘shell-treatment’) of some millimetres or centimetres. The depth of the protected zone depends on wood species and treatment process. While ‘shell-treatments’ might be adequate to achieve a sufficient protection against fungal decay by treatment with biocides, the effect on how wood treated by chemical wood modification systems performs with regard to the resistance against wood-destroying organisms, is not yet known. On that basis, this study aimed at examining systematically the ability of wood-destroying fungi to grow through modified wood and degrade an untreated underlaying wood zone. Hence, decay tests were performed with pure cultures of T. versicolor (wr), C. puteana (br) and terrestrial microcosm (TMC) containing soft rot fungi and other soil-inhabiting micro-organisms. The incubation period of segmented specimens of 20 (ax.) x 20 x 45 mm³ (modified mantle, untreated core/dowel) was 16 weeks and tests conducted according to CEN/TS 15083-1 (2005) and CEN/TS 15083-2 (2005). By light microscopy photographs it was shown that both white rot and brown rot and also soft rot fungi can grow through chemically modified wood. The latter was shown independent of the modification agent which was acetic anhydride (acetylation) or 1.3-dimethylol-4.5-dihydroxyethyleneurea (DMDHEU), the treatment level and wood species of the modified mantle specimens. Significant mass losses (ML) of untreated wood (dowels), surrounded by a modified wood mantle, indicated that chemical wood modification does neither inhibit fungal growth nor affect the ability to degrade untreated wood substrate.
L Emmerich, S Strohbusch, C Brischke, S Bollmus, H Militz


Durability of pine modified by 9 different methods
2004 - IRG/WP 04-40288
The decay resistance was studied for pine modified by nine methods of wood modification: 1) Acetylation, 2) Treatment with methylated melamine resin (MMF), 3) Acetylation followed by post-treatment with MMF-resin, 4) Thermal modification, 5) Furfurylation, 6) Maleoylation (using water solution of MG or ethanol solution of maleic anhydride), 7) Succinylation, 8) NMA-modification and 9) modification with reactive linseed oil derivative (UZA), Wood blocks of Scots pine (Pinus sylvestris L.) sapwood were modified in pilot plants. Methods 1-5 were performed by the authors at Chalmers University of Technology or at BFH in Hamburg. Methods 5-9 were part of a European research project (the Chemowood project, FAIR-CT97-3187) and therefore each of these modifications was performed by the project participant responsible for the method. For laboratory testing in TMCs (modified European standard ENV 807) and pure basidiomycete culture bioassays, smaller test specimens were cut from the modified wood blocks. Most of the modification methods were applied on test specimens for marine field testing (EN 275) and some methods to produce mini-stakes for field tests in five Swedish fields. Some modification methods result in modified wood with poor durability, whereas other methods (acetylation, furfurylation and MMF-treatment) seem to provide excellent resistance to microbial decay.
M Westin, A O Rapp, T Nilsson


Changed susceptibility of the chemically and thermally degraded spruce wood to its attack by the dry rot fungus Serpula lacrymans
1999 - IRG/WP 99-10322
In buildings, some intentional or unintended situations can occur at which some wood products are exposed to aggressive chemicals and also to higher temperatures. Occasional activity of fungi on such pre-attacked wood products can be either higher or lower. This paper deals with changes in the susceptibility of spruce wood (Picea abies L. Karst.) to attack by the dry rot fungus Serpula lacrymans, in such situations, when the wood samples 8.5x8.5x120 mm3 (RxTxL) were first pre-treated with 1% water solutions of selected acids (H2SO4, CH3COOH), bases (NaOH, NH4OH) or oxidizing agent (H2O2), or they were also exposed to a higher temperature (190°C/3h). The activity of S. lacrymans was totally restricted only in one situation, if the wood was pre-treated with sulphuric acid and then exposed to 190°C. On the other hand, specimens pre-treated with ammonium hydroxide were more susceptible to bio-attack (in both situations: without or with high temperature pre-treatment effect) than sound ones.
L Reinprecht


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


Decay resistance of high performance biocomposites based on chemically modified fibres
1998 - IRG/WP 98-40120
Different partners within the framework of a European research project produced high performance biocomposites aiming at the utilisation of board materials as durable products both in dimensional and biological degrading circumstances. This paper summarises test data, which indicate the potential of board materials produced with modified fibre material. The chemical modifications applied cover a range of technologies, which were selected for scaling up experiments. Acetylation, as well as alternative methods like maleiation, phthalylation, succinylation, oxidation and silylation were investigated. Fibre source, density variation and the use of several types of glues were parameters of the total set-up. Basidiomycete testing was carried out using specific methodology for board materials elaborated in CEN standardisation committees.
V Rijckaert, J Van Acker, M Stevens


Leachability of borate-modified oriented strandboard: A comparison of zinc and calcium borate
2002 - IRG/WP 02-40232
The leachability of boron in zinc and calcium borate-modified oriented strandboard (OSB) was investigated in this study. The leaching experiments were conducted by exposing edge-sealed OSB samples under running water for 8, 24, 72, and 216 hours. The results were compared with those from the unleached controls. Boron leaching of the modified OSB occurred upon the initial water exposure, and the leaching rate decreased as the leaching time increased. Borate type, initial BAE level, wood species, and sample thickness swelling significantly influenced the leachability. There was no consistent effect of polyethylene glycol (PEG) on zinc borate leaching. Calcium borate with a smaller particle size helped reduce its leachability. The glueline washing due to thickness swelling of the test samples under water and decomposition of the borate to form less water-soluble boric acid are thought to be two possible causes for the observed leaching. The relationship between assayed BAE and leaching time followed a decaying exponential function for zinc borate OSB and a Harris decaying power function for calcium borate OSB. The material constants of the regression models allow comparing leachability of the modified OSB for various wood species. A unified leaching method for treated wood composite materials is needed.
S Lee, Q Wu


Evaluating the potential of modified wood for use in marine environments using a short-term laboratory bioassay
2004 - IRG/WP 04-10525
Chemically modified wood may be an alternative to preservative treated timber for marine structures. In this study a screening laboratory test using the wood-boring isopod crustacean Limnoria quadripunctata was used to assess the durability of chemically modified Pinus sylvestris, Pinus radiata and Picea sp. Most of the treatments used a combination of one of two of types of the resin dimethyloldihydroxyethyleneurea (DMDHEU) and phosphobutane tricarboxylic acid (PBTC). Untreated Pinus sylvestris sapwood was used as a non-durable comparison. Small test sticks from different types of modified wood were prepared and leached in seawater for 8 days prior to the experiment. A wood stick with a Limnoria and 4 ml of seawater was placed in each 12mm diameter well of a cell culture chamber. The number of faecal pellets produced by the animals was measured under these forced feeding conditions, and activity and mortality was recorded. With some treatments, no faecal pellets were produced, with others more faecal pellets were produced than with untreated Pinus sylvestris. Non-production of faecal pellets was sometimes due to mortality, but in some treatments there were also evidence of antifeedant effects as there was no evidence of acute toxicity Limnoria. However, some moribund animals were observed in these treatments and there was significant reduction in the number of pellets produced, so chronic toxicity may be suspected. The Arkofix type of DMDHEU gave significantly higher protection against borers than DMDHEU NG. A dose-dependent suppression of pellet production by PBTC was also detected.
L M S Borges, S M Cragg, M van der Zee


The dry rot fungus Serpula lacrymans, its growth and damaging of wood
2004 - IRG/WP 04-10511
The dry rot fungus (Serpula lacrymans) is one of the most dangerous wood rotting fungi, especially in the built environment. In our mycological laboratory more experiments with this fungus have been carried out aimed at:- its growth under stable and variable climatic conditions, - its possibility to attack either natural wood of different species and also modified wood primary pre-treated with some other fungi, aggressive chemicals and high temperatures, - its influence on the molecular and anatomical wood structure, - its influence on the acoustical, electric, strength and some other properties of decayed wood which can be applied for its identification.
L Reinprecht


Microscopical analysis of formaldehyde-acid modified wood
1981 - IRG/WP 3182
Cross-linking of wood with gaseous formaldehyde improves its hygroscopic and dimensional behaviour, and its resistance against micro-organisms. However, formaldehyde cross-linking reactions take place only in the presence of an acid catalyst, which results in losses in mechanical By optimization of a formaldehyde-sulfur dioxide vapour phase process the reaction conditions were established to limit losses in modulus of elasticity and bending strength to a few percent. Under these circumstances, impact strength losses of about 50 to 75% were still noted. The reaction of formaldehyde with cellulose has been studied intensively in textile research. However little is known on the fundamental aspects of the interaction of formaldehyde with lignin and wood. In order to get further insight into the effects of a formaldehyde-acid catalyzed reaction on the technological properties of wood a fundamental analysis of the interactions of both compounds with wood has been carried out.
M Stevens, N Parameswaran


Prediction of Weight Percent Gain (WPG) of furfurylated wood by FT-NIR spectroscopy
2004 - IRG/WP 04-20295
Wood modification based on furfuryl alcohol improves several important wood properties, such as the resistance to fungal decay and insect attack, hardness, dimensional stability, bending strength and stiffness. The improvements of wood properties depend on the weight percent gain (WPG) due to furfurylation. Fourier transform near infrared (FT-NIR) spectroscopy was used to calibrate PLS-regression models for prediction of WPG due to furfurylation in birch wood. Spectra were obtained in cross-sections of solid wood. A PLS-regression model based on wood samples with WPG ranging from 16.7 to 35.1%, performed well when validated on a separate test set. The coefficient of determination between laboratory measured WPG and predicted WPG was high (R2 = 0.87). The prediction error given by the root mean square error of prediction was low (RMSEP = 1.23). The results showed that the technique should be considered a prospective tool for quality assessment of furfurylated wood.
M Eikenes, P O Flæte, E Ystrøm Haartveit, S Lande


A modified method to determine the toxic values of chemicals against Lyctus africanus (Lesne) by larval transfer method (laboratory method)
2005 - IRG/WP 05-20309
Lyctus africanus (Lesne) is the commonest species widely distributed by trade throughout India. It is one of the most important insect pest attacking logs, branchwood and and practically every kind of manufactured wooden article that contains sapwood. Presently, in India many short rotation and alternate timbers are being used for making many finished products .The inclusion of sapwood containing starch makes these products very susceptible to insect borer attack. Consequently, many wood preservative companies are coming out with many formulations to combat powder post beetle attack. Currently there exists no Indian standard to test these wood preservatives against the powder post beetle infestation. Since the testing using adult beetle releasing increases the testing period it is not much appreciated. As insect borer larval activity is visible to judge the progress of the test and also as it reduces the test period, a modified method to determine the toxic value of the chemicals against Lyctus africanus-Lesne by larval transfer method has been standardized based on the European standard EN21.
R Muthukrishnan, O K Remadevi


Improvement of some technological and biological properties of poplar wood by impregnation with aqueous macromolecular compounds
1992 - IRG/WP 92-3721
Poplars (Populus spp) belong to the most important tree species in afforestation programs of the Netherlands. Due to their rapid growth, the wood quality is usually low. Therefore, studies were performed to elucidate whether some technological properties and the resistance against fungal attack could be improved by impregnation with water-soluble resins. The results showed that swelling and shrinkage of poplar wood may considerably be reduced by a treatment with certain resins. The anti-shrink efficiency (ASE) strongly depends upon the resin type. An air-curing alkydresin based on polybutadiene and an air-curing acrylate modified alkydresin emulsion caused the best effects. Additions of wood preservatives to the resins further improved the ASE. Some disadvatages of the tested resins may be seen in their leachability with consequent loss of the dimension-stabilizing effects. The resins by themselves don't reveal fungistatic properties but an impregnation of poplar wood with these materials led in all cases to a better durability against Coniophora puteana and Coriolus versicolor. Leaching procedures influenced the durability in various ways. With resin/fungicide combinations, a good resistance against Coriolus versicolor could be reached even after leaching. SEM and EDXA methods were used to localize the resins in the cell walls and lumina and to detect the growth of mycelium in the specimens.
R D Peek, H Militz, J J Kettenis


Protection of rubberwood with modified creosote
1998 - IRG/WP 98-30165
Creosote is a renowned wood preservative but has certain disadvantages like obnoxius odour and colour, with its unpaintability and bleeding from wood surface may create environmental hazards. An effort has been made to isolate chemical fractions from creosote to obtain clean odourless preservative formulations by subjecting to steam distillation (SVC). Rubberwood treated with SVC and tested for its efficacy against wood rotters gave encouraging results. The potential use of SVC as effective clean preservative has been discussed.
H C Nagaveni, H S Ananthapadmanabha, G Vijayalakshmi, M N Sharma, K H Shankaranarayana


Influence of concentration, catalyst, and temperature on dimensional stability of DMDHEU modified scots pine
1998 - IRG/WP 98-40119
Dimethyloldihydroxyethyleneurea (DMDHEU) is being used in textile industry to improve wrinkle recovery. Trials on solid wood have been performed to minimise swelling of the wood. This paper focuses on the effect of various types and concentrations of catalyst and reaction temperature on the dimensional stability of Scots pine. Three different catalysts, NKS (based on magnesium chloride), 3282 (based on aluminium chloride) and citric acid have been tried separately or in combination with tartaric acid. Reaction temperatures between 100° and 125°C have been investigated. The results showed that an anti shrink efficiency of up to 50% can be obtained.
M Van der Zee, E P J Beckers, H Militz


Modified Wood – Methods, testing and applications: Outcomes of the EU-Thematic Network
2003 - IRG/WP 03-40268
In the last decade, interest in the development of wood modification systems has increased in Europe. Alongside several industrial initiatives for heat treatments, there have also been scaling up and pilot plant projects for chemical wood modification. Between 2000 and 2003, the European Commission funded the "Thematic Network on Wood Modification". This paper will feature the modification processes available and indicate their route to commercialisation to date. One of the key decisions of the Network was that modified wood should be regarded as a new wood species, and tested accordingly, with particular emphasis on biological durability and dimensional stability. Suggested ways to test and analyze modified wood are presented, along with some of the key findings of the Network.
D Jones, W Homan, J Van Acker


The biological effectiveness of wood modified with heptadecenylsuccinic anhydride against two brown rot fungi: Coniophora puteana and Gloeophyllum trabeum
1992 - IRG/WP 92-3705
A modified soil block test was carried out using wood samples reacted with heptadecenylsuccinic anhydride (ASA). This modification gave good resistance to decay brought about by the brown rot fungi Coniophora puteana and Gloeophyllum trabeum during the twelve week exposure period. Results indicated that there was a good correlation between increased loading of modifying reagent and an increase in effectiveness paralleled by a marked reduction in wood moisture content. The effective resistance threshold level was calculated to be about 30% weight gain of ASA. Further discussions regarding the mode of action are included.
C Codd, W B Banks, J A Cornfield, G R Williams


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