A comparative study on brown-rot fungus decay and subterranean termite resistance of thermally-modified and ACQ-C-treated wood

The resistance of thermally-modified and Alkaline Copper Quaternary type C (ACQ-C) treated aspen (Populus tremuloides Michx), jack pine (Pinus banksiana Lamb.), yellow-poplar (Liriodendron tulipifera L.), and Scots pine (Pinus sylvestris L.) against the brown-rot fungus (Gloeophyllum trabeum) and Eastern U.S. subterranean termite (Reticulitermes flavipes) was studied. Wood materials were thermally-modified at a temperature of 210 °C for 15 min. ACQ-C was impregnated into yellow-poplar and jack pine wood at three different retention levels and at each level both leaching and non-leaching procedures were conducted. Results indicate that ACQ-C-treated yellow-poplar and jack pine became significantly more resistant to the brown-rot fungus compared to the thermally-modified wood and the untreated control. Thermally-modified yellow-poplar and jack pine were more resistant to this fungus than untreated wood. For aspen and Scots pine, the resistance to G. trabeum was improved after the thermal modification, but it remained susceptible to this brown-rot fungus decay. Termite susceptibility of thermally-modified aspen, jack pine, and yellow-poplar was comparable to that of untreated controls. Significantly greater termite attack occurred on thermally-modified Scots pine wood than it did on untreated wood. This likely is attributed to some compounds contained in Scots pine wood that inhibited termite attack.     

Fungal and termite resistance of wood treated with 4-methoxytrityl tetrafluoroborate

This study evaluates the decay and termite resistance of Scots pine (Pinus sylvestris L.) treated with 4-methoxytrityl tetrafluoroborate (MTFB). Decay resistance tests of unleached samples showed that 2%, 1.5% and 1% concentrations of MTFB (15.4 kg/m³, 11.1 kg/m³, and 7.4 kg/m³, retention levels, respectively) gave less than 2% decay of Postia placenta and concentrations of 2% and 1.5% less than 2% decay of Coniophora puteana. Wood specimens treated with 4-methoxytrityl tetrafluoroborate solutions were not protected against the brown rot fungi after a 14-day severe leaching process, suggesting excessive leaching of the chemical from wood. Treatment with 2% concentration protected against subterranean termites, Coptotermes formosanus Shiraki based on mass losses in both leached and unleached wood specimens in comparison with lower concentration levels. These results suggest that 4-methoxytrityl tetrafluoroborate might be promising to protect wood being used outdoors against termite attack. However, 4-methoxytrityl tetrafluoroborate did not protect wood against fungal decay. Field tests are needed to observe the performance of 4-methoxytrityl tetrafluoroborate treated wood in ground contact.     

Effect of essential oil compounds and plant extracts on decay and termite resistance of wood

Essential oils and their derivatives have a long history of safe usage as antimicrobial agents in food industry. In this study various essential oils and extracts from plants were screened for their ability to inhibit wood decay and termite attack in laboratory decay and termite resistance tests using treated wood specimens. In the laboratory decay resistance tests, wood specimens treated with essential oil compounds were subjected to brown-rot fungus, Tyromyces palustris, and white-rot fungus, Trametes versicolor for three months. The specimens were also subjected to termite attack by subterranean termites, Coptotermes formosanus for three weeks in laboratory conditions. The formulation with cinnamaldehyde (DF3) was found to be effective against both the brown-rot and white-rot fungi used in the study. However, the formulation with cinnamic acid (DF8) was able to protect wood specimens against only the white rot fungus and about 50% mass loss occurred in the specimens subjected to the brown-rot fungus. The mass losses in the wood specimens treated with cassia oil containing formulation (DF4) showed that cassia oil was effective against both fungi. The wood tar oil and dodecanal compounds also inhibited fungal decay in the specimens. The wood specimens treated with the formulations used in termite resistance tests were more resistant against the termites when compared to specimens treated with the formulations in decay resistance tests. Even after severe weathering process, treated wood specimens showed resistance against the subterranean termites. Results suggest that essential oils and plant extracts might be important to develop new wood preservatives that are less harmful to the environment and humans than recently available ones.     

The suitability of structural particleboard made from fast-growing tree species

Wood particle gypsum boards were prepared in laboratory under the following conditions: wood particles from chips (Cryptomeria japonica, Paulownia X Taiwaniana, Aleurites montana) 30, 25, and 20%; gypsum 70, 75, and 80% by weight; water-gypsum-ratio 0.35; board density 1.1 g/cm³; pressure 30 kgf/cm²; post curing 8 to 10 days. The MOE (tested by stress-wave-timer) was 2,800.7–4,328.5 N/mm² and the MOR (tested by universal testing machine) was 4.74–10.25 N/mm²; the screw holding strength was ranging from 1.85 to 5.14 N/mm². The wood particle gypsum board made from Taiwan paulownia showed the highest value of mechanical properties. The thickness swelling and water absorption of bonded particleboard were 0.62–22.05% and 18.42 to 35.22% after 2 h soaking in water; 2.73–26.68% and 21.71–44.06% for 24 h soaking, respectively. The effect of gypsum content on mechanical properties of boards was not significant, but the thickness swelling and water absorption of boards were reduced as gypsum content increased.     

Boron addition to non- or low-formaldehyde cross-linking reagents to enhance biological resistance and dimensional stability of wood

Tyromyces palustris and Coriolus versicolor, which are the representative test fungi of brown- and white-rot in Japanese Industrial Standard (JIS) A-9201-1991, respectively. PBA had somewhat less contribution to decay resistance of GX most possibly due to chemical complexation. GA proved superior in decay resistance to the other two reagents. Mass loss due to the Formosan termite Coptotermes formosanus attack could be reduced to a minimum with total inactivation of termites by PBA addition. BA retention did not suffice to impart complete termite resistance after ten cycles of severe weathering of the specimens. Thus, BA was found appropriate to be added to the used cross-linking agents in such service conditions where decay risk is high while PBA combinations should be preferred if termite damage prevailes.

---

Tyromycetes palustris und Coriolus versicolor, die im japanischen Standardtest als als Vertreter für Braun- bzw- Wei?f?ulepilze verwendet werden. PBA liefert einen geringeren Beitrag zur Resistenzerh?hung durch GX, wahrscheinlich aufgrund der Bildung von Komplexen. GA erwies sich den anderen Reagenzien als überlegen. Massenverluste durch Angriff von Termiten (Coptotermes formosanus) konnten minimiert werden durch Zusatz einer PBA-L?sung. Das Rückhalteverm?gen von BA war nicht ausreichend um nach 10-maliger Bewitterung die Termiten zu inaktivieren. Daher ist BA eher geignet als Zusatz zu Vernetzungsreagenzien, wenn Pilzbefall abzuwehren ist, w?hrend PBA-Kombinationen bei Gefahr von Termitenbefall vorzuziehen sind.

     

Boron addition to non- or low-formaldehyde cross-linking reagents to enhance biological resistance and dimensional stability of wood

and Coriolus versicolor, which are the representative test fungi of brown- and white-rot in Japanese Industrial Standard (JIS) A-9201-1991, respectively. PBA had somewhat less contribution to decay resistance of GX most possibly due to chemical complexation. GA proved superior in decay resistance to the other two reagents. Mass loss due to the Formosan termite Coptotermes formosanus attack could be reduced to a minimum with total inactivation of termites by PBA addition. BA retention did not suffice to impart complete termite resistance after ten cycles of severe weathering of the specimens. Thus, BA was found appropriate to be added to the used cross-linking agents in such service conditions where decay risk is high while PBA combinations should be preferred if termite damage prevailes.     

Natural decay resistance of LVL made of veneers from durable and non-durable wood species

Laminated veneer lumber (LVL) was laboratory manufactured using veneers from decay and non decay resistant species in order to evaluate changes in the durability as a result of the LVL manufacturing process, and to test if the mixing of decay resistant species and non decay resistant species can improve durability. Laboratory soil block test and field test were conducted. The durability of solid wood was comparable to that of LVL made using the same species. For LVL made using veneer from durable and non-durable wood species, durability was improved when two faces and one core veneers were from decay resistant species.     

Improvement of termite resistance,dimensional stability and mechanical properties of pine wood by paraffin impregnation

Paraffin has been used as surface protection of wood throughout the ages but its use for impregnation to improve wood resistance to biodegradation is recent. This study determined the main improvements on wood properties with paraffin impregnation. Healthy Pinus pinaster Ait. wood was impregnated with paraffin at different levels using a hot–cold process. Weight gain, equilibrium moisture content and dimensional stability (ASE) at 35 and 65 % relative humidity, termite durability against Reticulitermes grassei (Clément), bending strength, bending stiffness (MOE) and Janka hardness were determined. Density increased from 0.57 to 0.99, ASE ranged between 38–96 % and 16–71 % for 35 and 65 % relative humidity, respectively. Equilibrium moisture content decreased from 9.9 and 12.0 % to 0.8 and 3.6 % for 35 and 65 % relative humidity. Termite durability improved from level 4 to level 3 of attack, and higher termite mortality was found in treated wood (52 % against 17 %). Bending strength (MOR) increased with paraffin weight gain, reaching a 39 % increase. MOE also increased by about 13 % for wood with a weight gain around 80 %. Janka hardness increased significantly reaching about 40 % for wood with 80 % weight gain. Paraffin impregnated wood has improved properties with regard to equilibrium moisture content, dimensional stability and density, bending strength and Janka hardness, and resistance against termites.     

Natural decay resistance of LVL made of veneers from durable and non-durable wood species

Laminated veneer lumber (LVL) was laboratory manufactured using veneers from decay and non decay resistant species in order to evaluate changes in the durability as a result of the LVL manufacturing process, and to test if the mixing of decay resistant species and non decay resistant species can improve durability. Laboratory soil block test and field test were conducted. The durability of solid wood was comparable to that of LVL made using the same species. For LVL made using veneer from durable and non-durable wood species, durability was improved when two faces and one core veneers were from decay resistant species.

---

Natürliche Fäulnisresistenz von Brettschichtholz aus haltbaren und nicht haltbaren Holzarten

Zusammenfassung Aus fäulnisunbeständigen und -beständigen Holzarten wurde in einem Labor Brettschichtholz hergestellt, um Veränderungen in der Dauerhaftigkeit auf Grund ihres Herstellungsverfahrens zu evaluieren, und um zu prüfen, ob das Mischen von fäulnisunbeständigem mit fäulnisbeständigen Holzarten die Dauerhaftigkeit von LVL verbessern kann. Bodentests wurden im Labor und als Freilandversuche durchgeführt. Bei Verwendung derselben Spezies war die Dauerhaftigkeit von massivem Holz vergleichbar mit derjenigen von LVL. Bei Brettschichtholz, welches aus resistenten und nicht resistenten Arten gefertigt war, wurde die Dauerhaftigkeit verbessert, wenn zwei Aussenschichten und eine Innenschicht aus einer fäulnisbeständigen Holzart war.

     

Leachability and termite resistance of wood treated with a new preservative: ammonium borate oleate

Synthesis of a new chemical compound combining water-repellence of oleic acid and biocidal effect of boric acid linked by ammonia have been followed and validated by fourier transformed infra red (FTIR). This compound named ammonium borate oleate (ABO) has then been studied as a wood preservative. Different molar ratios of oleic acid have been involved in the synthesis of ABO and leachability of those mixes from wood observed according to Japanese industrial standard. The formulation one mole of boric acid and one of ammonia (1:1:4) for four moles of oleic acid has shown the best efficiency compared to formulations 1:1:1, 1:1:2 and 1:1:3 with about 52% of boron remaining after weathering when other formulations retained respectively 10%, 29% and 46% of boron in the case of an impregnation of Cryptomeria japonica. Seven solutions of 1:1:4 ABO in ethanol of different concentrations were then produced and sapwood blocks of C. japonica and Fagus crenata were impregnated. A toxicity threshold of around 2.0 kg/m³ for both species was determined in a termite resistance test to Coptotermes formosanus indicating the positive effect of combining water repellent and biocide. Termite mortality recording and microscopic observations complete this study indicating that the action mechanism of ABO is providing a water resistant inner coating.     

速生杨木热压处理的研究

采用试验用热压机对速生杨木进行热压处理,比较不同条件下压缩对试材主要物理力学性能的影响。试验表明:热压处理对压缩木材的变形回复有较大的抑制作用,而且随着压缩率的增大,杨木试件的物理力学性能有明显改善。     

速生材改性处理研究的现状及发展趋势

本文介绍了速生材改性处理的研究现状,认为目前国内对木材进行改性处理的方法仍为常规的物理和化学处理方法。有鉴如此。提出了今后速生材改性处理研究趋势及主要潜力在生物酶处理改性和表界面性能的研究方面。通过对速生材进行酶处理与表界面性能的研究。可以发现速生材改性处理后。在木材工业中有着更加广泛的应用前景,是解决现阶段优质木材生产面临严重的原料危机这一主要矛盾的重要方法之一。最后,在对速生材进行物理、化学、生物改性处理研究时本文提出了需要注意协调的几个技术问题。     

Properties of fast-growing poplar wood simultaneously treated with dye and flame retardant

Simultaneous dyeing and inflaming retarding treatment improves both the aesthetic aspects and the safety value of fast-growing tree species. This study investigated the effects of water bath temperature, dye concentration, flame retardant concentration and dipping time on dye uptake and limited oxygen index of simultaneously dyed and fire-retardant-treated wood veneer. Through comprehensive analysis, an improved process was obtained and wood with these improved properties was prepared. Analyses of chemical structure and thermal stability of prepared wood samples were conducted, as well as crystallinity and microscopic morphologies using Fourier transform infrared spectroscopy, thermogravimetric, plus X-ray diffraction and scanning electron microscopy and energy-dispersive X-ray spectroscopy. Results showed that dye uptake and limited oxygen index had a similar increasing tendency with increased water bath temperature and dipping time. Moreover, dye uptake improved upon addition of flame retardant, while limited oxygen index decreased as dye concentration increases. Flame retardant combined with the wood fiber and was in the absence of chemical reaction with the dye used. Dye and flame retardant molecules diffused into the cell cavity, wood vessel and aperture. Furthermore, the fire-retardant properties and crystallinity of wood simultaneously treated with dye and flame retardant were both improved.     

Evaluation of particulate zinc and copper as wood preservatives for termite control

Subterranean termites are a major factor in the biodegradation of wood construction products. In this study the efficacy of wood treated with micronized copper, zinc oxide and their mixture was compared to that of wood treated with soluble amine copper oxide against subterranean termites in a laboratory test. All of the formulations tested were effective in controlling wood degradation by the termites, with copper being slightly more effective than zinc and micronized copper being slightly more effective than amine copper.     

Using iron catalyst to enhance the drying properties of crude tall oil-based wood preservative

Crude tall oil (CTO) is known to be capable of preventing moisture uptake by wood. One problem limiting its use for industrial wood protection is its tendency to exude from the wood. Because of the lack of oxygen, oil polymerization does not occur inside the wood, and the unpolymerized oil may exude from it in time to form a pitch-like surface. The aim of this work was to investigate the potential of iron for catalyzing the CTO oxidation process and to determine the optimum amount of iron catalyst needed. The latter was decided on the basis of differential scanning calorimetry (DSC) measurements and an inclined-plane test. Both methods proved that the drying properties of pure CTO are too low for it to be used as such in wood preservation but its oxidation rate can be greatly enhanced by means of iron catalysts so that oil exudation from the wood can be prevented.