The use of hardwood railway sleepers in Australia is limited by hardwood timber resources. Softwood sleepers made from plantation Radiata pine (Pinus radiata) may replace them. Low permeability of pine heartwood does not allow to impregnate them well with preservatives. Microwave (MW) wood modification increases heartwood permeability and improves preservative distribution and uptake. The experimental study of MW sleeper modification and impregnation allowed the rational MW process parameters and preservative treatment schedules to be determined, with an estimate of the effect of MW treatment on sleeper quality. Tests of MW modified and impregnated with Copper Naphthenate oil preservative sleepers in a railway track allowed to assess sleeper conditions after 3.5 years of service and provide recommendations to the industry. The costs of MW sleeper processing are acceptable to industry and provide good opportunities for commercialization.

Paulownia is a very fast-growing hardwood species with low density and low strength properties. These limit the industrial use of this species. Manufacturing of composite material from Paulownia wood with applications resins can increase its density and improve mechanical properties. Paulownia is practically impermeable and therefore cannot be impregnated with industrial resins that could improve essential physical and mechanical properties. High-intensity microwave (MW) modification converts Paulownia wood to a highly porous material "Torgvin" with very high permeability for liquids and provides opportunities to impregnate it with special resins for manufacturing composite material with higher mechanical and physical properties. In this work, the results of the experiments on developing technology for manufacturing composite material from plantation Paulownia (Paulownia fortunei) wood are presented. The technology of the new material "Vintorg" manufacturing includes sawn timber MW modification, kiln drying, pressure impregnation by resins, hot pressing, and finishing. The strength tests showed that the new material has a significant increase in strength properties compared to natural wood. This provides an opportunity to use Paulownia timber as a row material for manufacturing composite materials with the required mechanical properties. Economic analyses showed reasonable material production costs. The significant increase in material strength properties compared to Paulownia natural wood and reasonable production costs provide good opportunities for technology commercialization in small-scale mills.

The protection of wood from biological degrade is critical to increasing the service life of timber. Eucalyptus species have low permeability for liquids and are difficult to impregnate with preservatives. Microwave (MW) wood modification significantly increases wood permeability and improves preservative distribution and uptake. Plantation Blue gum (Eucalyptus globulus) heartwood has very low permeability for liquids and cannot be impregnated with water-based preservatives. Microwave wood modification can solve this problem. An experimental study was carried out to determine the feasibility of practical use of MW Blue gum log modification for preservative treatment. The 300 kW MW conveyor plant at frequency 0.922 GHz was used for experiments with green logs. After MW conditioning logs were pressure impregnated with water based preservatives copper-chromarsenic (CCA). The preservative distribution in the log cross sections and uptake were analysed. Experimental studies of microwave Blue gum log modification and impregnation with preservatives demonstrated the effectiveness of the process. Main MW processing parameters have been determined. A cost analysis of MW conditioning of round timber indicates costs of US$63-$129/m3 depending on electricity costs in the range US$0.10 to $0.25/kWh and process requirements. These costs are acceptable for industry and provide good opportunities for commercialization of the new MW technology.

Wood properties of young teak (Tectona grandis L.f.) is inferior, and then preservative treatment is one possible solution to enhance its service life. The uptake and movement of preservatives through wood cell structure is directly connected to the wood permeability. There are two simple methods to identify wood permeability: water soaking and bubble test methods. This paper assesses the young teak permeability by water soaking and bubble test methods. The assessment was conducted into five cm thick young-teak discs by soaking in the red-dye water and blowing air into the discs which had been coated with soap. Results show that the heartwood is less permeable than sapwood. Red-dye penetrates almost 100% of the sapwood area, and the red-dye did not penetrate in the heartwood. Red-dye only penetrates in the cracked heartwood through the void volume in the cracking heartwood. There is a transition zone between sapwood and heartwood, and it is refractory. Bubble test with air pressure from compressor could open the air-pathway in the heartwood and sapwood of young-teak discs taken from Bogor. The bubble test result of young-teak discs from Madiun showed air-pathway only in the sapwood, but heartwood. The air pressure is not capable of moving the vapour through the wood cell. It indicates that the heartwood of young-teak from Madiun is less permeable and less possibility for pressure treatment.

Low permeability of many wood species causes problems during timber manufacturing, including long drying times, material losses after drying, and expensive drying processes. Impregnating low permeability timber with preservatives and resins is extremely difficult. In the pulp and paper industry, use of low permeability wood results in shallow chemical penetration, and it requires the use of small-sized chips, high chemical usage, and high-energy consumption. Microwave (MW) wood modification technology can provide solutions to many of these problems. The wood structural changes in Norway spruce and radiata pine after MW modification with 0.922 and 2.45 GHz of were investigated. High intensity MW application (specific MW power 22 to 25 W/cm3, applied energy 79 to 102 kWh/m3) to moist wood caused the following wood structural changes: pit opening and pit membrane rupture; middle lamella weakening and rupture; and ray cell wall destruction and check (voids) formation mainly in the radial-longitudinal plane caused by the destruction of rays and weak middle lamella regions. Microwave destruction of different wood structure elements provided a significant increase in wood permeability for liquids and gases. Knowledge of the effects of MW treatment to the wood structure elements allows assessment of opportunities for the use of microwave irradiation in wood technology.

Based upon successful chemical modification of wood, bamboo strips were subjected to furfurylation treatment. Furfurylation in the mean of impregnating furfuryl alcohol to the bamboo and then heated at 100°C for 24 hours to produce solid polymeric resin. The success of furfurylation is assessed by uptake and the weight percentage gain of furfurylated bamboo strips. However, the treatability of dry bamboo strip is relatively poor. This paper studies the furfurylation process of bamboo betung (Dendrocalamus asper Backer ex K.Heyne) strips by soaking, vacuuming and the combinations thereof. Results showed that soaking bamboo strips for two days after vacuum treatment achieved optimum uptake of furfuryl alcohol solutions and gave rise to an 80% weight gain. Catalyst addition during furfurylation did not increase the weight percent gain. Water was an active solvent carrier for achieving higher weight gains

Bamboo material is a potential wood substitute given that its physical and mechanical properties are comparable with those of wood. As lignocellulose material, bamboo is also degraded for use outdoor. Two significant chemical modification for wood which may work for bamboo material are acetylation and furfurylation. This paper evaluates the weathering performance of furfurylated and acetylated bamboo sheets. Parameters studied include colour changes and contact angle after accelerated weathering process at QUV chamber. The result shows that the total colour differences ( E*) of furfurylation is higher than non-modified strips, while colour differences of acetylated bamboo strips are less than nonmodified strips. To summarize, chemically modified Sheets turn grey after weathering. Slowing of lignin photo-degradation by acetylation is attributed to the acetyl groups, which limits the degradation of lignin. Treating bamboo sheets with acetic anhydride and furfuryl alcohol was found to be effective in protecting bamboo from absorbing water during weather exposure.

Dyeing of veneer is an important value-adding process, particularly for young plantation hardwood species, which often have uneven colour and “dull appearance”. An important indicator in the assessment of the performance of veneer dyeing process is the dye uptake. This study compared two different methods of measuring dye uptake of dyed veneers; by using either liquid uptake based method or spectrophotometry method. The study revealed that there was a significant difference in the percentage of dye uptake determined by the two methods, but the overall results in the correlation between the percentage of dye uptake and the dyeing parameters had a similar trend.

This study investigated the dyeing methods (soaking and vacuum-pressure), types of dye (direct dye and reactive dye), and dyeing parameters (dye concentration, dyeing time, and temperature) in the veneer dyeing process for Eucalyptus globulus grown on plantations in Australia. The dyed veneers were assessed in two ways: dye penetration, which was determined using ImageJ software, and visual veneer grading for identifying any damage (curves or cracks). Veneers with different moisture content (MC) levels were used and were called green veneer (80% ± 5% MC) and dried veneer (12% MC). The study showed that the reactive dye Procion Brown P2RN at a concentration of 2% resulted in a significantly higher dye penetration than the other dyes. Soaking was not recommended as the dyeing method for this species because the dyed samples were severely damaged by the pre-treatments and high temperatures. A dye penetration of 100% was achieved when using the vacuum-pressure method with a dyeing time of 120 min, a pressure of 1000 kPa, and the addition of 20 g/L of sodium chloride. The results of this study can be applied in further research on the veneer dyeing process for this species.

To investigate the potential application of vacuum-pressure methods for dyeing low-quality hardwood veneers produced from young, small-diameter logs, Eucalyptus globulus veneers were dyed with a 2% solution of the reactive dye Procion Brown PX-2R at a vacuum of -100 kPa for 15 min prior to pressure being applied. The effects of various pressures and pressure times on dye uptake, dye penetration, and colour change were evaluated. Veneers with varying moisture content (MC) were used and were labeled as green veneer (80% +/- 5% MC) or dried veneer (12% MC). The dyeing method was based on the results of the preliminary experiments. The vacuum-pressure method had remarkable influence on the dye uptake, dye penetration, and colour change, particularly when the samples were dyed at a pressure of 1000 kPa and pressure time of 120 min. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy results indicated that the reactive dye was able to react with the wood compounds, and scanning electron microscopy (SEM) analysis showed that the ray parenchyma cells provided an effective radial path for dye penetration.

The use of microwave (MW) technology is growing in all industries. This increased use has resulted from the high efficiency of converting electricity into MW energy; energy savings associated with rapid, in-depth heating of materials; specific interactions that can be achieved between MW energy and materials; radical acceleration of technological processes; reductions in MW equipment costs; and improvements in the reliability of industrial MW equipment. The new technology of MW wood modification is based on the supply of high-intensity MW power, up to 135,000 kW/m(3) at frequencies of 0.922 and 2.45 GHz. Such power induces significant changes to the microstructure of wood and a dramatic increase in wood permeability. A number of commercial applications have been developed based on the fundamental changes in wood structure. These include the treatment of refractory wood species with preservatives, rapid drying of hardwoods, relief of growth and drying stresses in timber, manufacture of the new wood materials Torgvin and Vintorg, and modification of logs, sawn timber, and woodchips for pulping. MW equipment and processing parameters have been developed for three applications that are ready for commercial use. The technology provides significant material and energy savings and will give a new impetus to product development in a very traditional industry. The costs of microwave timber processing range from AU$22 to AU$69 per m(3). These costs are acceptable to industry and potentially provide wide appeal for use in the timber, biocomposite, and pulp and paper industries.

The Unitreat or Conveyor belt treatment process utilizes residual vacuum trapped in the wood to improve preservative distribution, once the treated commodity has been removed from the treatment plant (Vinden 2003). Unlike traditional industrial wood treatment technologies, (Bethel, Lowry and Rueping processes) limited quantities of preservative are metered into the wood rather than using traditional methods of treating to refusal or low final rates of flow. This paper explores a range of treatment options that benefit from this technology. Highlights of the technology include: (a) very short and low pressure treatment periods, whilst maintaining full sapwood penetration (b) absence of any final vacuum with no preservative dripping or wood sugar contamination of preservative. (c) hot treatments with very rapid preservative fixation and no sludge formation (i.e. reaction between CCA preservatives and wood sugars in the parent solution). Industrial applications of the Unitreat technology include: (a) treatment of pressure steamed green pine round-wood with copper-chrome-arsenic preservatives, (b) conveyor belt processing using microwave technology, (c) treatment of framing timber with water-based boron preservatives, (d) vapour phase treatment with boron preservatives, (e) chemical modification, (f) antisapstain chemical impregnation. Large-scale microwave conditioning substitutes high-pressure steaming and provides conveyor belt treatment processes whereby trees are converted into poles or railway sleepers that are ready for use within minutes rather than days or weeks. Most importantly, treatment with microwave technology extends the number of wood species that can be preservative treated by rendering the wood more permeable. This is achieved by micro-incising the wood during microwave processing.

Lower moisture content in wood, preferably 5-6%, is desirable for many chemical modification reactions. Economically, it is not feasible to dry timber to such low moisture content by conventional drying without drying degrades. Microwave heating was evaluated and found to be effective in reducing the moisture content of radiata pine from 13% to 6% in a microwave cycle of two minutes. The energy consumption is about 55kWh/m(3). Moisture distribution profiles demonstrate very uniform drying across the sample thickness. The findings suggest that microwave heating can potentially be applied to condition wood in a very short period of time.

Wood hardness is an important property for flooring, furniture products and structural utilization. Currently wood hardness can only be measured using destructive testing. As there is no suitable method for predicting wood hardness from standing trees, developing a non-destructive technique to predict wood hardness from plantations trees would provide significant benefits for evaluating optimal silvicultural treatments, and for selecting trees for tree improvement programs. It is proposed initillay that a possible non-destructive test may be developed using „crystallinity“ characteristics (degree of crystallinity (DC), crystalite width (CW) and length (CL) and microfibril angle (MFA)) determined using X-Ray diffraction. The aim of this study was to test the feasibility of using crystallinity as a non-destructive indicator of wood hardness. Experimentally, nine trees were taken representing small, medium and large diameter from five-year old fast growing teak plantation forest in Ciampea, Bogor, Indonesia. Wood hardness and crystallinity were determined following a standard testing regime. The results showed that MFA was negatively related to all hardness directions. Crstallite width only influenced side hardness with negative correlation, while degree of crystallinity only affected the end-grain hardness with positive correlation. Different vertical positions within tree only influenced the end-grain hardness value, while different radial positions had no effect on wood hardness. The optimum sampling height was found to be 80 cm, 130 cm, and 100 cm for radial, tangential and end-grain hardness, respectively. The relationship was based on the height that provided the highest correlation with the whole tree hardness values. Proposed models involving density and „crystallinity“ for predicting wood hardness are presented. While the R2from the proposed models was mostly less than 0.50, however, the approach described provides a new way to predict wood hardness from 10 mm increment cores at standing trees.

Particleboard and solid wood stakes were treated with either an isocyanate or phenol formaldehyde resin and exposed in soil beds comprising three different soil types and two moisture contents. The treatments resulted in a marked improvement in the dimensional stability of particleboard but had no effect on solid wood. Higher moisture uptakes in stakes exposed in sandy soils indicated that the technique used for measuring soil water holding capacity needs to be reviewed.

This study outlines the effect of catalyst (potassium acetate) and microwave heating on the rate and degree of acetylation in radiata pine. Sapwood samples were impregnated with potassium acetate dissolved in two different solvents (water and methanol). Catalyst loaded samples were dried and impregnated with acetic anhydride followed by conventional and microwave heating. The degree of acetylation was evaluated by weight percent gain (WPG) and characterized by Fourier transform infrared spectroscopy using attenuated total reflection (FTIR-ATR). Effect of catalyst loading, reaction temperature, and reaction time on the degree of modification and rate of reaction was investigated. A reaction time of 30 min gave rise to 20.6% weight gain in a catalyzed system while it was only 2.7% in uncatalyzed condition. No significant difference in the WPG and rate of reaction was found when water and methanol were used as solvents. Under catalytic condition 21.6% weight gain was obtained after 10 min of microwave heating. Potassium acetate was found to have no adverse effect on dimensional stability of wood.

The use of hardwood railway sleepers in Australia is limited by hardwood timber resources, thus softwood sleepers made from plantation Radiata pine ( Pinus radiata ) may replace them. Low permeability pine heartwood does not allow for good impregnation with preservatives. Microwave (MW) wood modification increases heartwood permeability and improves preservative distribution and uptake. The experimental study of MW sleeper modification and impregnation, allows for the rational MW process parameters and preservative treatment schedules to be determined, with an estimate of the effect of MW treatment on sleeper quality, and for recommendations to be provided to industry. On the basis of the research results a 400 kW commercial MW plant capable of an output of 100,000 sleepers per annum has been designed. The costs of MW sleeper processing are acceptable to industry and provide good opportunities for the commercialization.

Drying time of hardwood can be remarkably shortened by microwave(MW) pretreatment.Wood degradation with MW pretreatment,compared with a traditional long seasoning process,was decreased and high quality timber yield was increased.A cost-effective analysis showed that the MW pretreatment was about 4.1% to 4.9% of the price of low quality dried lumber,or 2.3% to 2.8% of high quality lumber.

Radiata pine (Pinus radiata) peeler cores are classified as a by-product of plywood manufacture and have the potential for development as value-added solid wood products. This article outlines technical and cost analyses of microwave surface modification of radiata pine peeler cores along with the methodology, including measurements of temperature distribution and of preservative uptake and distribution following microwave heating. After microwave treatment, the highest temperatures are observed on the surfaces of the peeler cores. A gradual decrease in temperature is noted with depth within the timber. Chromated copper arsenate uptake after pressure impregnation ranges between 94 and 314 liters/m 3 . This uptake is three to nine times higher than that of control timber (no microwave treatment). Cost analyses focus on the microwave treatment of peeler cores and indicate that microwave modification costs range from US$0.95 to US$1.23 for one peeler core (i.e., US$29 to US$37 per m 3 ), depending upon electricity charges and the number of working shifts employed.