Your search resulted in 343 documents. Displaying 25 entries per page.
Modification of solid wood: research and practical potential
1997 - IRG/WP 97-40098
The polymeric structure of the wooden cellwall mainly consists cellulose, hemicellulose and lignin. The most reactive sites on these components are the hydroxyl groups. The cellwall polymers (and its reactive hydroxyl groups) are responsible for most physical and chemical properties of wood. By changing the basic chemistry of the cellwall polymers, it is possible to change different undesirable at...
H Militz, E P J Beckers, W J Homan
Biological degradation resistance of wood acetylated with thioacetic acid
1983 - IRG/WP 3223
Chemically, modification of wood is being considered as an alternative to conventional preservation by toxic chemicals. Acetylated wood has been reported to be quite resistant to most biodegrading organisms at weight percent gains (WPG) around 15-19. The conventional acetylation techniques with acethic anhyrdride result in generation of acetic acid. However, acetylation with thioacetic acid overco...
S Kumar, S C Agarwal
Three years of field tests with "Lignomer" stakes in ground contact
1981 - IRG/WP 3166
The "Lignomer" (Wood Polymer Composite) is a material obtained during the polymerisation of various monomers or its mixtures in wood. As laboratory tests have shown, this material is characterized by a high resistance against biological deteriorating agents. The laboratory investigations on the durability of various materials against biological deterioration are in many instances extended by field...
K Lutomski
A new vacuum/pressure plant system
1988 - IRG/WP 3479
In the subtropical regions, the problem of wood supplying becomes more and more difficult to be solved. In that context, the Centre Technique Forestier Tropical had paid a particular attention to the valorization of products issued from plantations in dry zones of Africa. In these plantations, the products of clearings can be used as fencing, stakes or for traditional construction. However in thes...
C Dalois, R Schwartz, G R Y Déon
Microdistribution of water-borne preservatives in blue gum treated by full-cell process
1990 - IRG/WP 3617
The present work deals with the study of the microdistribution of copper, chrome and arsenic elements in Eucalyptus globulus Labill. sapwood, treated with a CCA water-borne preservative by full-cell process, with the help of scanning electron microscopy together with energy dispersion X-ray analysis technique. The work shows that the retention of CCA elements is high in vessels and vasicentric par...
D De Sousa Castro Reimão, J M Palacios
Gaseous preservative treatment of wood
1990 - IRG/WP 3631
A recent development in processing wood with a gaseous preservative means that dry, treated wood can be produced in under 30 hours with the benefits of product diversification, faster stock turnover and the ability to respond to short term demand. About 400,000 m³ of wood are treated each year in New Zealand with boron salts to protect from borer infestation. Traditionally this treatment is effec...
R Burton, A J Bergervoet, K Nasheri, P Vinden, D R Page
Screening of the technical performance and aquatic toxicity of N-methylolacrylamide treated wood
2000 - IRG/WP 00-40166
In the course of the last decades chemical modification of wood species, with a limited natural durability, has been subjected to intensive research. As a possible alternative and supplementary treatment of non-durable wood in a range of applications it remains one of the major topics in the wood preservation world. Different modification systems have been scaled-up and are now in an industrialisi...
V Rijckaert, S De Geyter, J Van Acker, M Stevens
Characteristics of thermally modified wood in vacuum
2004 - IRG/WP 04-40287
In commercial thermal wood modification processes nitrogen, steam or oil has been used for the reduction of oxygen content in the reactor atmosphere. In present study no special heating medium, but an initial vacuuming step has been used for this purpose. Mass loss, resistance to fungal decay, dimensional stability, bending strength and modulus of elasticity of heat treated wood were evaluated and...
G Rep, F Pohleven, B Bucar
Internal pressure development within Oriented Strand Board during supercritical fluid impregnation
2000 - IRG/WP 00-40175
Supercritical fluids (SCF) offer an attractive alternative to conventional treatment processes for delivering material into wood, but there are many unanswered questions concerning the technology. One major concern is the potential for the development of excessive pressure gradients in the wood that might exceed the material properties and lead to crushing or other pressure-induced damage. Previou...
G Oberdorfer, P E Humphrey, R J Leichti, J J Morrell
The resistance of timbers to impregnation with wood preservatives
1979 - IRG/WP 3137
It is anatomical structure which determines liquid flow rate within different timber species. This cannot be deduced from properties such as density or rate of growth, and can only be found by experiment. A standard test has been in use at the Princes Risborough Laboratory for many years, employing a pressure-impregnation treatment, and a large number of timbers have been studied. The test consist...
Anonymous
Effect of fungal degradation on the chemical composition of acetylated beech wood
2003 - IRG/WP 03-40267
This study investigated the impact of fungal attack on the chemical composition of acetylated wood. Beech wood acetylated to different degrees was exposed to decay by the white-rot fungus Trametes versicolor under solid-state fermentation conditions. Laboratory soil-bed assays were also conducted to study the degradation of acetylated wood by soft rot fungi and other soil-inhabiting microorganisms...
H Militz, Dong-won Son, L Gómez-Hernández, R Sierra-Alvarez
Test methods for modifies wood: The EU-Thematic network approach
2002 - IRG/WP 02-20255
The last decade wood modification systems have become new wood treatment methods in Europe. Alongside several industrial initiatives for heat treatments also scaling up and pilot plant projects for chemical wood modification have recently been carried out. In 2000 an initiative to create a network related to these new developments was supported by the European Commission. Within the work proposed ...
J Van Acker, D Jones
Impregnation of timber with tannin as a mean of improving its dimensional stability
1992 - IRG/WP 92-3695
The results of a joint project carried out at the Timber Division of LNEC under the 2nd research programme of the CEC DGXII - "Wood as a renewable raw material" entitled "Stabilization of wood by impregnation processes" is presented. Pieces Maritime pine timber was impregnated with tannin under pressure to see if the treatment with tannin improved the behavior of wood regarding its dimensional sta...
J S Machado
Melamine resins as preservatives results of biological testing
1996 - IRG/WP 96-40061
Based on previous work of the authors on resins, the upgrading of wood with a true solution of a methanol etherificated melamine resin in low aqueous concentration was performed. For the relative assessment of the biological resistance against brown and white-rot fungi were used not only untreated controls of pine sapwood (Pinus sylvestris L.), but also heartwood of European larch (Larix decidua M...
A O Rapp, R-D Peek
Characterization of wood decay enzymes by MALDI-MS for post-translational modification and gene identification
2002 - IRG/WP 02-10442
The recent sequencing of the Phanerochaete chrysosporium genome presents many opportunities, including the possibility of rapidly correlating specific wood decay proteins of the fungus with the corresponding gene sequences. Here we compare mass fragments of trypsin digests, determined by MALDI-MS (Matrix Assisted Laser Desorption Ionization-Mass Spectrometry), with predicted mass fragments derive...
T H de Koker, P J Kersten
Fixation of chromated wood preservatives through technical drying
1990 - IRG/WP 3623
Twin samples of sawn timber of Pinus sylvestris and Picea sp. were treated with copper-chromate-containing wood preservatives and subsequently kiln resp. air dried. After drying, the distribution of preservative and rate of fixation were determined. Drying of freshly treated wood in a condenser type kiln at temperatures of 60°C and 80°C and in a vacuum type kiln at 55°C with a pressure of about...
R-D Peek, H Klipp
Effects of the sulfuric acid modification of CCA treating solution
1987 - IRG/WP 3415
Sulfuric acid modification of CCA treating solution is often used to control the formation of sludges and undesirable deposits on the surface of treated wood. The consequences of sulfuric acid addition are examined in this work and negative effects are shown to far outweigh any benefits. Major risks include the loss of copper due to leaching from treated wood and the accelerated corrosion of treat...
R F Fox, H J Fry, E A Pasek, A S Ross
The potential of high pressure pulsation processes to treat white spruce lumber with water-borne preservatives
1988 - IRG/WP 3471
Laboratory work using end sealed 4x8x46 cm³ white spruce samples has been done to explore the suitability of three variants of a 2.1 MPa pulsation process for the impregnation of white spruce with CCA. The results showed that the process improved significantly the penetration of the preservatives and reduced significantly cell collapse, when compared with the results of treatment using a 2.1 MPa ...
J P Hösli, J N R Ruddick
The susceptibility to sludging of sulfate and oxide CCA
1990 - IRG/WP 3599
Radiata pine sapwood was treated separately with a sulphate CCA-C and an oxide CCA in a pilot scale pressure plant using a full cell process. CCA solutions were recovered from the final vacuum phase, placed in plastic tubes, and their susceptibility to sludging determined by examining changes in solution pH, time required for sludge to form and weight and chemical composition of sludge formed. Sul...
B T Mutandadzi, P D Evans
Blue Staining of Coated Modified and Unmodified Wood
2006 - IRG/WP 06-10589
We investigated resistance of unmodified, DMDHEU modified and oil heat treated uncoated and coated Scots pine wood against blue stain fungi. Both EN 152-1 and the reverse exposure tests showed excellent resistance of DMDHEU and especially of oil heat treated wood against blue staining. It is not needed to add any additional protective coating layers to prevent modified wood from staining. However,...
M Petric, M Pavlic, M Humar, M Tomažic
High-energy multiple impact (HEMI)-test – Part 2: A mechanical test for the detection of fungal decay
2006 - IRG/WP 06-20339
The suitability of the high-energy multiple impact (HEMI)-test for detection of early fungal decay was examined. The HEMI – test characterizes the treatment quality of thermally modified wood by stressing the treated material by thousands of impacts of pounding steel balls. This method differentiates between heat treatment intensities, which are expressed by structural changes of the wood. Simil...
C R Welzbacher, C Brischke, A O Rapp
High-energy multiple impact (HEMI)-test – Part 1: A new tool for quality control of thermally modified timber
2006 - IRG/WP 06-20346
Thermal modification processes improve durability and dimensional stability of wood, but the strength properties, especially the dynamic ones, are compromised and need to be considered with respect to industrial quality control. Results from standard dynamic strength testing, such as impact bending tests, suffer from high variability, and therefore require a high number of replicates. To overcome ...
C Brischke, A O Rapp, C R Welzbacher
The effect of woody and non woody plants extractives on microbial resistance of non-durable species
2006 - IRG/WP 06-30392
The effect of Elm (Zelkova carpinifolia), Oak (Quercus castanifolia), Mulberry (Morus alba), Ash (Fraxinus excelsior) as woody plants, Rose (Rosa damascene) and Fumitory (Fumaria sp) as non woody plants extractives on durability of Beech (Fagus orientalis), Maple (Acer insgin), Alder (Alnus subcordata), and Lime (Tilia sp) were studied. First wood species having extractives were cut to small piece...
S M Kazemi, A Hosinzadeh, M B Rezaii
The commercialisation of ThermoWood® products
2006 - IRG/WP 06-40339
The concept of thermally modifying timber is well established, which has achieved a limited market breakthrough to date. Commercial application has mainly occurred within Finland, though recent years has seen market gain in several other European countries. This paper reviews the known properties of ThermoWood® timber, based on the combined work of the Finnish ThermoWood® Association, alongside ...
D Jones, E Suttie, J Ala-Viikari, N Bergstrom, D Mayes
Further discussion of biological durability assessments of acetylated wood from several European institutes
2006 - IRG/WP 06-40340
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 2000-03, the European Commission funded the "Thematic Network on Wood Modification". This paper features a re-evaluation of work undertaken...
D Jones, W Homan, F Bongers