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Bibliography: Interactions of wood preservatives with wood, metals, glues, paints and concretes
1983 - IRG/WP 3271
H Becker

Comparisons of differences in electrical conductivity and corrosivity between CCA-oxide and CCA-salt treated wood
1981 - IRG/WP 3178
CCA preservatives have served well in many applications throughout the world. In developed areas it is the preservative in demand for clean dry paintable surfaces with long durability. In developing areas it is widely used for economic and logistical reasons. With the current emphasis on energy resources, the CCA preservatives are gaining greater acceptance as a substitute for hydrocarbon-related preservatives. While there are several formulations with apparent wide differences in the proportions of active ingredients, (chrome, copper and arsenate), the performance of each appear to be essentially equivalent as wood preservatives. This performance has lead to an almost blind acceptance in the market place in the U.S. in that any CCA is considered equivalent in all respects. When all aspects are considered, it is readily apparent that this equivalency does not exist.
J A Taylor

The effect of wood preservatives on the relation between the electric resistance and moisture content in scots pine (Pinus sylvestris L.) sapwood
1998 - IRG/WP 98-20142
The effect of two types wood preservatives (TBTO and CuHDO) on moisture content measurements with an electric resistance meter in pine sapwood is assessed. High and low concentration impregnated pine sapwood is climatized at different relative humidities. Once climatized the samples are weighed and the moisture content is measured with an electric resistance meter by fixed stainless steel, isolated measuring pins. Subsequently the wood is dried for 48 hours at 103°C and weighed to gain the correct climatized moisture content. The reading values of electrical moisture content measurements are compared to the actual moisture content. Compared to the original correction lines for pine, an increase in concentration of metal ions leads to a steeper slope, i.e. the conductivity of the treated wood increases. The change in conductivity is so small that electrical resistance measurements are still practicable. However, for precise measurements new correction lines, which depend on concentration and type of preservative, need to be established.
B W Holleboom, W J Homan

The fate of salt preservatives in facility yard soils and decontamination of soils and drainage waters
1993 - IRG/WP 93-50001-25
Extensive studies during the past 10 to 15 years revealed that noticeable amounts of preservative components may be released in the environment by dripping off or by rain prior to fixation unless adequate precautions are taken. Therefore, soil and groundwater contamination especially from chromium-VI compounds but also from other inorganic and organic constituents exist in impregnation plants, possibly endangering the soil and groundwater ecosystem. The actual risk potential originating from chromium-containing wood preservatives in a practical situation are to be studied in the frame of a comprehensive research programme sponsored by the German Ministry of Research and Technology (BMFT). Accompanying laboratory investigations are performed with the aim of assessing the various types of water-soluble wood preservatives with respect to whether or possibly which compounds remain mobile und thus bio-available in the soil. Special attention is drawn to the question as to which effective constituents are adsorbed to soil particles depending on the mineralogical-geological composition of the soil, and at what situation the retention capacity for effective components of different soils would be exceeded. The results of the pilot study and of parallel running laboratory tests serve as a basis of deterioration analyses for grading and assessing the endangering potential in the ecosystem and shall provide a basis for the choice of adequate remedial concepts and measures to avoid such environmental impacts.
R-D Peek, H Klipp, K Brandt

Study of properties and application of Paulownia in wood industries
2011 - IRG/WP 11-40560
Important of required raw material supply regarding constraint in harvesting, increasingly population, change in consumption pattern and increasingly focus on wood products and per capita in consumption is obvious for anyone. Paulownia is a marvelous tree species with its characteristics of fast-growing, good Wood quality, multiple uses, wide-ranged distribution, easy propagation, deep root system and sparse crown. The fiber length (0.83 mm) of this wood, which is close to low end of the hardwoods but fiber diameter was very wide, similar to that of softwoods. Paulownia has one of the highest strength to weight ratios of any wood. Strength modus of rupture MOR (psi) of Paulownia is 5740. Otherwise has been widely used for fine furniture, musical instruments, carvings and decorative finishes for over 1000 years. It can be peeled for veneer in 1/16 inch thickness and has even been sliced at 1/32 inch. Air-drying takes as little as 30 days. Boards can be kiln dried at high temperatures in as little as 24 hours to 10% to 12% moisture content with no warping. Shrinkage from green to oven-dry is only 2.2% radial and 4.0% tangential.
M Akhtari

Copper naphthenate treatment for wood pols - a review and update
2012 - IRG/WP 12-30600
This paper reviews copper naphthenate (CuNap) and its utility as a treatment for wooden utility poles. One of the principal reasons that CuNap has gained market acceptance, in addition to its efficacy against decay fungi and wood-destroying insects, is its low mammalian toxicity. CuNap is a well-proven non-restricted use preservative, used extensively and specified for environmental reasons by utilities across the US, and recently adopted by a Class One railroad to replace creosote in both their poles and ties. This paper reviews the efficacy of CuNap in laboratory and long-term field tests with an emphasis on the properties of wood treated with CuNap, including permanence of preservative, conductivity and climbability. An update on the regulatory status of copper naphthenate is also given, including disposal options for treated wood. CuNap is already likely to increase in importance due to both economic and efficacy performance, but future disposal concerns are also likely to increase its specification as a preferred preservative system.
J A Brient, M H Freeman

Effect of silver nanoparticles on the rate of heat transfer to the core of the medium-density fiberboard mat
2014 - IRG/WP 14-40653
Effect of silver nanoparticles on the rate of heat transferred to the core section of medium-density fiberboard (MDF) mat was studied here. A 400 ppm aqueous nanosilver suspension was used at three consumption levels of 100, 150, and 200 mL/kg based on the weight of dry wood fibers; the results were then compared with the control MDF panels. The size range of silver nanoparticles was 30-80 nm. Results showed that the uniform and even dispersion of nanoparticles throughout the MDF-matrix significantly contributed to the faster transfer of heat to the core section. As to the loss of mat water content after the first 3 – 4 minutes under the hot press, the core temperature slightly decreased in the control panels. However, heat-transferring property of silver nanoparticles contributed in keeping the core temperature rather constant in the NS150 and 200 treatments. As to the de-polymerization of part of the resin in the surface layers of the mat due to the rapid absorption of heat from hot plates by the nanoparticles, it can be concluded that the optimum nano-suspension content should not necessarily be the highest one.
H Reza Taghiyari, O Schmidt, E Bari, P M Tahir, A Karimi, P Nouri, A Jahangiri

Increasing the hardness of wood-composite panels by nanosilver
2016 - IRG/WP 16-40715
Effect of silver nanoparticles on hardness in medium-density fiberboard (MDF) was studied here. A 400 ppm aqueous nanosilver suspension was used at three consumption levels of 100, 150, and 200 mL/kg, based on the dry weight of wood fibers; the results were then compared with the control panels. The size range of silver nanoparticles was 30-80 nm. Composite mats were hot-pressed for 6, 8, and 10 min. Results showed that the uniform and even dispersion of nanoparticles throughout the MDF-matrix significantly contributed to an increase in the hardness at lower hot-press time of 6 min. In the longer hot-press times, however, over-heating of the mat resulted in significant a decrease of hardness values. Significant high correlation was observed between water absorption and thickness swelling.
H R Taghiyari, J Norton, K Heidarhaee

Effects of Nano-Wollastonite Impregnation on Fire Properties of Some Thermally-Treated Solid Wood Species
2017 - IRG/WP 17-40771
The effects of nano-wollastonite (NW) suspension impregnation on the fire-retarding properties of heat-treated solid wood of three species (beech, poplar, fir) were studied. Heat treatment was performed at two temperatures of 180 °C and 200 °C. Impregnation was carried out at a pressure of 3 bars for 30 min. The fire properties included ignition time, glowing time, back-darkening, back-splitting, back-firing, and length and width of the burnt area. Both impregnation with NW and heat-treatment generally improved all fire-retarding properties, although not always to a significant level. As a mineral material, NW acted like a physical shield against fire penetration into the texture of wood specimens, thus improving fire properties. Moreover, the high thermal conductivity coefficient of wollastonite increased the thermal conductivity of wood, therefore preventing the accumulation of heat at the point nearest to a piloted flame and contributing to the improvement of fire properties. The chemical degradation of wood cell components caused by heat-treatment further improved the fire properties. Cluster analysis indicated the significant effect of species on fire properties. Significant R-square values were found amongst fire properties related to the spread of fire on the surface of specimens. The combination of thermal modification and impregnation with NW provides suitable fire properties for solid wood.
H R Taghiyari, R Hossinpourpia, S Adamopoulos, A Jahangiri, D Rabie