Your search resulted in 343 documents. Displaying 25 entries per page.
Effects of a formaldehyde and sulphur dioxide treatment on decay and mechanical properties of aspen waferboard
1983 - IRG/WP 3242
Aspen wafers were sequentially treated under vacuum with formaldehyde and sulfur dioxide gas and pressed into waferboard bonded with powdered phenol formaldehyde resin. Decay resistance and strength properties were determined before and after simulated weathering. The water resistance of the phenol bonding system was lost in board made from the gas-treated wafers. This white rot fungus Coriolus ve...
E L Schmidt
Dynamics of pressure changes in wood during impregnation
1990 - IRG/WP 3615
Conventional methods of impregnation have to be improved for achieving better penetration of refractory wood species. Basic requirements for an adjustment of treatment schedules are, amoung others, a profound knowledge of the course of pressure changes in the wood during treatment. A new method of pressure measurement was developed which supplies exact and reproducible data. The results show that ...
R D Peek, S Goetsch
Photo-discoloration and Degradation of Wood and its Stabilisation by Modification with Benzoyl Chloride
2004 - IRG/WP 04-40274
Photo degradation of Pinus roxburghii (chir pine) and Hevea brasiliensis (rubber wood) was studied under artificial accelerated weathering conditions in a Xenon test chamber. The irradiated samples were analyzed for color changes and chemical changes. Analysis of colour changes in wood surfaces by UV-Vis. irradiation was carried out using a colour measuring (CIELAB) system and chemical changes ...
K K Pandey
Bending properties of TCMTB-treated Southern pine sapwood using supercritical carbon dioxide impregnation process
1997 - IRG/WP 97-40080
The effects of elevated pressure and treatment with thiocyanomethylthiobenzothiazole (TCMTB) on the bending properties of Southern pine sapwood were evaluated at pressures ranging from 1,800 to 3,600 psi. All bending properties were affected to some extent by supercritical fluid treatment. Modulus of elasticity and work to maximum load were not significantly affected by pressure levels. Modulus of...
Gyu-Hyeok Kim, S Kumar, E S Demessie, K L Levien, J J Morrell
Impregnation of roundwoods by sap-displacement in Madagasca
1975 - IRG/WP 352 E
The use of roundwoods is already very important in Madagascar and steadily increasing for the following applications: - posts, electricity and telephone line supports (medium voltage) - stakes, piles for civil engineering structures, bridges, gantries, road and port works, etc. - construction of houses (posts, frameworks, piles, etc.) and rural buildings (sheds, stables, piggeries) - fence posts, ...
M Fougerousse, P Guéneau
Determination of fixation properties by bioassays - A proposal for the assessment of safety indexes in wood protection
1990 - IRG/WP 3566
In the determination of environmental effects of chemicals tests with fishes, daphnia and algae have proved to be practicable. With respect to wood protection such bioassays are suitable to control effects of treated timber against aquatic organisms. By using the fish-acute-toxicity-test the development of a laboratory test method is described for the checking of the fixation rate of a copper-chro...
H-W Wegen
Recent developments in the treatment of sawn spruce by double vacuum impregnation
1978 - IRG/WP 3114
The timbers used for building purposes in the U.K. and on the Continent of Europe are mainly softwoods. The two types of wood most used are redwood (Pinus sylvestris) and whitewood (Picea abies or Picea sitchensis). Other species are used to a lesser extent when considerations such as a long length requirement or width requirement demand the use of, for example, hemlock, Douglas fir or Parana pine...
C T Kyte, L D A Saunders
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...
M Stevens, N Parameswaran
Improving the weather resistance of glue-laminated jarrah and karri
1994 - IRG/WP 94-40017
Surface modification and dimensional stabilisation significantly increased the dry and wet shear strength of karri and jarrah lap-shear specimens (laminates) bonded with resorcinol formaldehyde. The combination of surface modification (sanding/sodium hydroxide treatment), and furfurylation produced the highest dry and wet shear strengths. Acetylated laminates had the lowest dry bond strength, but ...
J Balfas, P D Evans
An inclination incising technique for the preservative treatment of refractory timbers
1991 - IRG/WP 3664
An inclination incising technique for preservative treatment of refractory timbers was examined by changing cutting angle to the longitudinal direction of test specimen and by using different types of knife edge. Incised wood were impregnated locally into incisions with CCA solution by the specified local pressure process. Width and length of penetration areas of CCA solution were measured on long...
Y Nakamura, K Nishimoto
Paper for discussion - Incising of spruce to improve preservative penetration
1973 - IRG/WP 318
Large quantities of whitewood or Norway spruce (Picea abies) are regularly imported into the United Kingdom from continental Europe. In addition, increasing amounts of Sitka spruce (Picea sitchensis) are likely to become available over the next decade from the Forestry Commission. In many ways spruce is a good structural timber, eg it is relatively cheap and easily available, it has adequate stren...
W B Banks
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 shrink...
R D Peek, H Militz, J J Kettenis
Improvement of wood decay resistance by tannin impregnation
1991 - IRG/WP 2380
The fungical effect of tannins is appraised after exposure of treated woods samples to wood rotting fungi. A screening-test is carried out with several solutions containing extracts of two kinds of tannins; a condensed tannin derived from Quebracho heartwood (Schinopsis sp.) and a hydrolyzable one extracted from chestnut heartwood (Castanea sativa Mill). If a fungicidal action was indeed found it ...
D Dirol, A Scalbert
A study on the pressure impregnation of Eucalyptus globulus fence posts with CCA preservatives. Part 1
1988 - IRG/WP 3470
This paper describes the impregnation with CCA preservatives by full-cell process of Eucalyptus globulus fence-posts. Several treatments were made for different times of initial vacuum and treating pressure, with fence-posts from two coppice plantations (1st and 2nd rotations), assembled into three diameter classes: small, medium, large. The results concerning the absorption and lateral penetratio...
D De Sousa Castro Reimão, L Nunes
Probing red maple pit membrane pore size at FSP and OD using polystyrene macromolecules
2001 - IRG/WP 01-40217
A modified solute exclusion technique was used to pressure impregnate a polystyrene molecular weight (MW) series dissolved in styrene into red maple samples at approximately the fiber saturation point (FSP) and oven dry (OD). Radial penetration was less than tangential and FSP less than OD. There was a marked penetration change with MW in the tangential direction, although there appeared to be a ...
A Omidvar, M H Schneider, A R P Van Heiningen
Commercial potential of the four-cycle method for the impregnation of green beech sleepers in Yugoslavia
1975 - IRG/WP 347
This paper was presented to the Conference on Wood Protection held in Sarajevo (Yugoslavia) in 1973. The paper was based partially on the report prepared by J. Struhar and G. F. Franciosi, who were appointed in 1972 as FAO consultants to demonstrate the new impregnation process for green beech sleepers in Yugoslavia. The so-called 4-cycle method was developed at the State Forest Research Institute...
N Vidovic
Influencia de la impregnación con soluciones tánicas en la estabilidad dimensional de la madera de Pinus pinaster Ait. procedente de España
1992 - IRG/WP 92-3686
En virtud de la importancia que presenta la madera de Pinus pinaster Ait. en el sector constructivo español, se ha sometido a esta a tratamientos en autoclave con distintas soluciones tánicas naturales y artificiales a fin de estudiar su incidencia en la estabilidad dimensional frente a exposiciones exteriores. En el estudio se pone de manifiesto el efecto creado por el tratamiento protector en ...
J A Rodríguez Barreal, J Cubillo Jordan de Urries, L Garcia Esteban
Application of roller-pressing method to the novel liquid impregnation treatment of green timber
2001 - IRG/WP 01-40198
A transverse compression technique enabled us to impregnate liquid into green timber through replacement of the free water in the timber with a treatment liquid without any critical physical damage to the timber by the roller-pressing method. The roller-pressing is supposed to remove free water the cell cavities and to concurrently introduce the treatment solution into green timber in the treatmen...
M Inoue, K Adachi, K Tsunoda, Y Imamura, S Kawai
Thermal modification of non-durable wood species 1. The PLATO technology: thermal modification of wood
1998 - IRG/WP 98-40123
The PLATO technology is an innovative upgrading technology with low environmental impact, which can be applied to fast grown and non-durable wood species. This technology is based on a thermal modification of solid wood without the addition of chemicals (e.g. preservatives), consisting of a hydrothermal treatment, followed by drying and curing. The PLATO technology results in a substantial improve...
M J Boonstra, B F Tjeerdsma, H A C Groeneveld
Improvements of stability and durability of beechwood (Fagus sylvatica) by means of treatment with acetic anhydride
1991 - IRG/WP 3645
In the present investigations, beechwood (Fagus sylvatica) was treated with non-catalysed acetic anhydrid at 120°C and some physical- and biological parameters of the treated wood were compared with those of non-treated wood. The radial and tangential shrinkage and swelling, respectively, and the absorption capacity of the acetylated wood against moisture is considerably lower. The durability aga...
H Militz
Preliminary results of the treatment of wood with chlorosilanes
1981 - IRG/WP 3172
It is clear from the initial data reported here that the treatment of pine sapwood with chlorosilanes under the reaction conditions employed did not significantly reduce the decay by both white rot and brown rot fungi. Only the dichlorosilane compounds showed to possess some protective action against fungal attack. Before drawing conclusions on the application of organosilicon compounds as potenti...
M Stevens
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 (bas...
M Van der Zee, E P J Beckers, H Militz
An investigation of the effects of pre-steaming on the treatment of sawn spruce timber with Celcure A, a copper/chrome/arsenic preservative
1981 - IRG/WP 3180
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. The growth characteristics of spruces (Picea spp) make them attractive candidates for forestry schemes. In 1975 the UK Forestry Commission had about 400 000 hectares, about 20% of total UK forest area, planted with Sitka spruce (Picea sitchensis)...
C R Coggins
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 process...
D Jones, W Homan, J Van Acker
Selective chromate elimination from the storage-drainage-water of a wood impregnation plant
1980 - IRG/WP 3153
With the Enviro-Chrom-Ex process it is possible to eliminate ecologically and economically hexavalent chromium (chromate) from water selectively. The process which is based on the principle of selective ion exchange works with different chromate concentrations and under the presence of other ions, irrespective of the water hardness. The values of water-offtake reach 0.1 mg CrVI at maximum, causing...
O Wälchli, R Ott, R Hugener, E Graf, B Lieberherr