Your search resulted in 216 documents. Displaying 25 entries per page.
Fenton's reagent as a modification tool in brown-rot decay
1996 - IRG/WP 96-10155
A biomimetic approach was used to clarify the role and importance of the Fenton-type reaction in the carbohydrate degradation by brown-rot fungi. Spruce sawdust and microcrystalline cellulose were modified in the H2O2/Fe(II) treatment. The degree of hydrolysis of the pretreated spruce sawdust was clearly increased with the complete cellulase (Econase), purified endoglucanase from Trichoderma reese...
M Rättö, A-C Ritschkoff, J Buchert, L Viikari
Steam/hold/APM boron treatment - Treatability trials with green gauged radiata pine
1987 - IRG/WP 3439
Freshly sawn 100 x 50 mm radiata pine was green gauged, steam conditioned and preservative treated with a mixture of borax and boric acid using a modified Alternating Pressure Method (APM) treatment schedule. A 12 hour holding period between steam conditioning and treatment resulted in the necessary moisture loss and moisture re-distribution to facilitate treatment to NZ Timber Preservation Author...
P Vinden
Studies on the resistance of DMDHEU treated wood against white-rot and brown-rot fungi
2005 - IRG/WP 05-10566
Beech wood (Fagus sylvatica) modified with the textile finishing agent 1,3 dimethylol-4,5-dihydroxyethylen urea (DMDHEU) has shown to improve durability against the white-rot fungus Trametes versicolor. In a mini-block test, the weight loss over eight weeks of incubation decreased with increasing weight percent gain (WPG) of DMDHEU. At 25% WPG, no significant weight loss was observed, while untrea...
P Verma, C Mai, A Krause, H Militz
Efficacy of anhydrides as wood protection chemicals
1997 - IRG/WP 97-30162
Wood samples treated with anhydrides of various compositions have been examined for their decay resistance and moisture behaviour. For this purpose two brown rot fungi (Coniophora puteana and Gloeophyllum trabeum) and two white rot fungi (Trametes versicolor and Pycnoporus sanguineus) were used in conventional and modified soil block tests. The modified soil block tests conformed to the method as ...
S C Forster, M D C Hale, G R Williams
The effects of chemical modification on the physical properties of alder and spruce particleboards
2005 - IRG/WP 05-40300
In this paper, it was aimed to improve some physical properties of chemically modified particleboard, made from spruce and alder species, spreading widely at Black sea region in Turkey. Spruce and alder chips were reacted with acetic, succinic, maleic and phthalic anhydrides at constantly heat for 3 hours then, hot pressed at 150 °C by using Phenol formaldehyde (PF) resin. Target board density wa...
E Dizman, Ü C Yildiz, H Kalaycioglu, S Yildiz, A Temiz, E D Gezer
Sphaeroma terebrans Bate: A note on distribution and preservative tolerance in Florida coastal waters
1987 - IRG/WP 4135
Treated test panels were installed in January 1984 in a Florida estuary where Sphaeroma terebrans had severely damaged pilings treated with copper chromate arsenate (CCA). Test treatments were CCA at three retentions, coal-tar creosote at three retentions, creosote with chlorpyrifos, dual treatment with CCA and creosote, and three types of chemical modification of the wood test panels. We describe...
B R Johnson, E D Estevez, S A Rice
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 ...
C Codd, W B Banks, J A Cornfield, G R Williams
Modification of wood by graft treatment
2003 - IRG/WP 03-40257
New water-repellent systems for wood are needed to improve the weathering characteristics. This study found that treatment of wood with chemical grafting systems imparted substantial water repellency. Different direct oxidative grafting systems were examined. Specifically, KMnO4, Fe(NH4)(SO4)2·12H2O, Fe2(SO4)3·5H2O, and (NH4)2Ce(NO3)6 were used as initiators and styrene as the monomer. All the...
M M Morshed, D D Nicholas, C Pittman Jr, T Schultz
Investigation of the suitability of silver fir (Abies alba Mill.) for thermal modification
2004 - IRG/WP 04-40275
In this study the suitability of silver fir (Abies alba Mill.) was examined for thermal modification. Comparative experimental investigations were performed with silver fir and Norway spruce (Picea abies Karst.) after thermal treatments. Besides properties, which characterize the quality of heat treatments, like dimensional stability and resistance against fungal attack, strength properties of the...
C Brischke, A O Rapp
Durability aspects of (hydro)thermal treated wood
2000 - IRG/WP 00-40160
Samples of several wood species were treated in a two steps process, subsequently hydrothermal and dry heat-treated, by the so-called PLATO-process and analysed for their resistance against fungal attack. Both PLATO-treated and dry heat-treated specimen were prepared and analysed, in order to study the influence of moisture during hydrothermal treatment of wood. The resistance against all of the s...
B F Tjeerdsma, M Stevens, H Militz
Effect of some resin treatments on fungal degradation reactions
1999 - IRG/WP 99-10318
The effect of impregnation of wood with vegetable oil, tall oil and two water soluble on fungal degradation reactions was assessed by hydrolysis and enzyme activity measurements. The experiments were carried out by using isolated enzyme preparations and a living brown-rot fungus Poria placenta. The results indicate that the inhibitory effect of treatments was clearly directec towards the enzymatic...
A-C Ritschkoff, M Rättö, A J Nurmi, H Kokko, A O Rapp, H Militz
Tunnelling bacteria
1983 - IRG/WP 1186
The micromorphology of decay in wood caused by a certain group of single-cell bacteria, called tunnelling bacteria (TB), is described. TB are characterised by their tunnelling ability within the secondary cell walls of wood fibres. Pure cultures of TB have not yet been obtained although the typical decay patterns can be reproduced using mixed bacterial cultures. Some indications of lignin degradin...
T Nilsson, G F Daniel
Influences of the hydro-thermal treatment on physical properties of beech wood (Fagus orientalis)
2005 - IRG/WP 05-40303
Influences of the hydro-thermal treatment on physical properties of beech wood were studied. Wood specimens (2×2×2cm) were treated in two steps. At first step, samples were treated at 160,180 & 200ºC for 4, 5 & 6 hours. At second step, treated samples were cured based on their first step treatment temperatures (160,180 & 200ºC) for 16 hours. The treated samples were soaked in water...
B Mohebby, I Sanaei
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 ...
R E Ibach, B-G Lee
Thermal modification of non-durable wood species 2. Improved wood properties of thermal treated wood
1998 - IRG/WP 98-40124
Properties of wood treated in a new heat-treatment process called the PLATO-process have been studied. Several wood species have been treated using this new thermal modification process using a range of process conditions (mainly time and temperature). In this study the characteristics of the treated wood were determined using samples from whole planks treated on pilot plant scale. The modified ch...
B F Tjeerdsma, M J Boonstra, H Militz
Microwave modification of wood properties - Improvements in wood permeability
2000 - IRG/WP 00-40181
A new method of microwave (MW) wood modification is described. Microwave irradiation of timber provides an improvement in wood permeability mainly in the radial and longitudinal directions. This is achieved by physically modifying ray cells and forming a large number of cavities in the radial - longitudinal planes. More extensive MW irradiation of different species transforms the wood into a new m...
G Torgovnikov, P Vinden
Dimensional stability and decay resistance of wood upon modification with some new type chemical reactants
1994 - IRG/WP 94-40028
Solid wood of home grown species can be upgraded by chemical modification with environmentally acceptable chemicals. The best kwown example of modification reaction is acetylation with acetic anhydride. A continued search for reactive chemicals other than acetic anhydride is ongoing, aiming at the improvement of technical properties of wood. This contribution deals with the results of a screening ...
P Goethals, M Stevens
Assessing the bioresistance conferred to solid wood by chemical modification
1997 - IRG/WP 97-40099
The chemical modification of wood using straight chain alkyl anhydrides can considerably enhance its durability. This paper presents an assessment of the effectiveness of these modifiers in improving the biological resistance of a susceptible softwood when exposed to four different basidiomycete fungi, soft rots and the larvae of the house longhorn beetle (Hylotrupes bajulus). It was clear that so...
E D Suttie, C A S Hill, D Jones, R J Orsler
Bending properties of wood after its decay with Coniophora puteana and subsequent modification with selected chemicals
1999 - IRG/WP 99-40146
Mechanical properties of wood are often decreased due to decay processes caused by biotic and/or abiotic factors. Damaged wooden elements (e.g. historical structures) can be reinforced by more methods, including their modification with convenient chemicals. This paper presents influences of selected chemicals on basic bending properties (modulus of elasticity - MOE, modulus of rupture - MOR) of so...
L Reinprecht, S Varinska
Comparison of thermally modified wood originating from four industrial scale processes – durability
2002 - IRG/WP 02-40229
This study examined the differences in biological wood properties of heat treated wood originating from four different European industrial heat treatment plants. The manufacturers of heat treated material were: PLATO Hout B.V./Netherlands, Thermo Wood/Finland, New Option Wood/France and Menz Holz/Germany where Oil-Heat treated Wood (OHT) is produced.
The results of miniblock tests with basidiomyc...
C R Welzbacher, A O Rapp
The kinetics of anhydride modification reactions of wood. Experimental results and theoretical modelling
1998 - IRG/WP 98-40125
Although the chemical modification of wood remains a fertile area for research, there has been little work performed on the kinetics of the modification process. The reaction kinetics of a series of linear chain and cyclic anhydrides has been studied and activation energies of the reaction determined. The reaction kinetic profiles are determined by the relative rates of reaction of the reagent wit...
C A S Hill, J G Hillier
Microwave modification of Yellow Stringybark (Eucalyptus Muelleriana) posts for impregnation with Copper-Chrom-Arsenic (CCA) preservatives
2000 - IRG/WP 00-40185
Yellow Stringybark posts with diameters ranging from 60-100 mm were microwave conditioned using a 60 kW microwave (MW) generator. A substantial improvement in heartwood penetration of preservatives and relaxation of growth stresses was indicated such that there was no split formation following drying of the posts. High preservative absorption of copper-chrome-arsenic (CCA) was achieved ranging fro...
G Torgovnikov, P Vinden
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