Improvement of fungicidal properties and copper fixation of copper-ethanolamine wood preservatives using octanoic acid and boron compounds

Copper ethanolamine preservatives are one of the most important solutions for wood preservation. As copper itself can not ensure sufficient protection against wood destroying organisms we combine it with other co-biocides like quaternary ammonium compounds, azoles and/or boron. Influence of different boron compounds and octanoic acid on copper fixation as well as performance of spruce wood impregnated with different copper/ethanolamine/boron based aqueous solutions is described in this paper. Copper fixation was determined according to the modified ENV 1250 (1994) standard method, while performance against Antrodia vaillantii, Gloeophyllum trabeum and Trametes versicolor was tested according to the mini block procedure. The results showed that addition of boron increases copper leaching, but on the contrary improves performance against wood decay fungi. On the other hand, addition of octanoic acid improves copper fixation, and slightly decreases resistance against copper tolerant fungi.     

Tannin-boron preservatives for wood buildings: mechanical and fire properties

The remarkable biological properties of tannin-boron wood preservatives for outdoor applications have been investigated recently (Thevenon et al. in Eur. J. Wood Prod. 67:89, 2009). In the present paper mechanical and fire-proofing attributes of these formulations are determined. Mechanical properties of Scots pine and beech specimens treated with tannin-based formulations were examined in compression and bending strength tests and surface hardness was determined. The tannin-hexamine formulations reticulated into the wood structure improve the strength of the treated specimens. The treated samples which underwent compression, bending, hardness and gluing tests showed improvements of on average 20%. Fire tests have been monitored regarding short and long flame exposure time. Short tests such as ignition, flame and ember time have allowed the ignition of the fire to be simulated, while the weight loss tests have provided a good overview of the behavior of the specimens during prolonged fire. A positive effect on fire-resistance is shown when wood is treated with tannin formulations. The fire-proofing properties of the resin have been upgraded adding boron and phosphorus. The ember time of the pieces treated using this method can be reduced by up to ten times.     

High performance tannin resin-boron wood preservatives for outdoor end-uses

Fixation of boric acid as a low toxicity wood preservative to decrease markedly its leachability was undertaken. Preservative systems based on the cross-linking and hardening of condensed tannins by hexamine, where boric acid is complexed onto the network, were found to markedly slow down the leaching of boron. They significantly enhanced wood durability before and after leaching once tested towards basidiomycetes according to the guidelines of EN 113. A particularly virulent fungal species was used for the tests. Further immersion of the wood so treated in hot unsaturated vegetable oil does yield comparable results.     

Evaluation of termiticidal activity of coconut shell oil and its comparison to commercial wood preservatives

Among several factors leading to biodegradation of wood, termites are one of the most damaging agents to wooden structures worldwide. To avoid environmental pollution and health problems caused by the use of synthetic pesticides, wood preservation research is currently focusing on discovery and application of termiticides derived from plants. This paper reports and discusses the use of coconut shell oil (CSO) as a potential termiticide. Termiticidal activity of CSO was assessed and compared to wood preservatives currently in use. After 18 months of field trial, all the control stakes were destroyed completely and there was damage of 34.2 % in the CSO brush coated stakes. CSO is a promising new biodegradable compound which can be utilized for the development of a termiticide of biological origin.     

The use of blood protein in wood preservatives

Tested formulations containing blood protein and copper(II) sulfate compounds were subjected to the accelerated leaching test. The tests were performed according to EN 84 as well as by means of atomic absorption spectrophotometry (AAS). Wood samples obtained from pine sapwood (Pinus sylvestris L.) were treated with selected formulations. The treated samples were then subjected to leaching with a simultaneous analysis of the active component (Cu(II) ion) contained in the water extracts. The potential large-scale opportunities for the application of animal blood proteins investigated in this study are: fixation of the CuSO₄ to the wood matrix through the protein denaturation and utilisation of the blood protein in industrial timber preservation.     

Application of copper monoethanolamine solutions as primers for semitransparent exterior wood stains

The effects of copper monoethanolamine (CuA) treatment of wood surfaces on the surface weathering and durability of a semitransparent penetrating stain were compared with those of chromic acid (CrA) treatment which is known as a photoprotective primer, using artificial weathering trials. Chemical changes in chemically treated and untreated wood surfaces during artificial weathering were investigated using Fourier transform infrared (FTIR) spectroscopy. Surface roughness, water contact angle measurements and scanning electron microscopy observations were performed to assess stain durability. Results of FTIR analyses indicated that lignin losses following CuA and CrA treatment were less than those of the untreated wood surfaces during the initial stage of artificial weathering. CuA pretreatment prior to staining also retarded the increase in the average surface roughness compared with that observed for the CrA-pretreated surface and untreated control (only stained) during artificial weathering. Furthermore, CuA pretreatment retarded the decrease in the contact angle compared with that observed for the untreated control, although the use of a highly concentrated CuA solution led to a decrease in the water repellency of the stained wood surface. These results indicated that CuA solution could be used for the pretreatment of wood surfaces to enhance the durability of semitransparent penetrating stains, as long as excessive CuA concentrations are avoided.     

Bioassaying combinations of wood preservatives and tannins withPoria placenta andAspergillus niger

With “new” preservatives it is convenient to be able to screen their efficacy before time consuming and expensive fungi tests are carried out. For a fast screening of preservatives, combined with natural and synthetical tannins, two screening tests withAspergillus andPoria, respectively, had been used. The results had been compared with soil block tests. With both screening tests, reproducible and distinctive results are given even after a couple of days. However, the comparison with the soil block test showed, that the result from the screening tests are not reliable for a later use of timber in soil contact.     

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 fixation time on leaching of copper-ethanolamine based wood preservatives

Fixation in copper-ethanolamine treated Norway spruce wood is finished in the first or in the second week after impregnation depending on the concentration of wood preservatives used. However, copper losses increased after four weeks of fixation again, presumably due to lignin depolymerisation caused by ethanolamine.     

Effect of fixation time on leaching of copper-ethanolamine based wood preservatives

Zusammenfassung Fixation in copper-ethanolamine treated Norway spruce wood is finished in the first or in the second week after impregnation depending on the concentration of wood preservatives used. However, copper losses increased after four weeks of fixation again, presumably due to lignin depolymerisation caused by ethanolamine.      

铜纤维与木单板的复合

为了赋予木基复合材料电磁屏蔽功能,在脲醛树脂胶中加入黄铜纤维导电单元,制备三层结构的落叶松复合胶合板,研究不同施加量和不同长度的导电单元以及涂胶量对木基复合材料电磁屏蔽性能 (SE) 和胶合强度 (ST) 的影响.结果表明,胶合强度均达到或超过国家标准.涂胶量增大对电磁屏蔽效能有不利影响.在黄铜纤维长度相同 (6～7 mm) 的条件下,电磁屏蔽效能为6.34～28.76dB,吨磁屏蔽和胶合强度模型均不显著;在黄铜纤维施加量相同 (120g/m2) 的条件下,电磁屏蔽效能为15.61～35.01dB,电磁屏蔽模型均显著,胶合强度模型不显著.黄铜纤维的加入一方面有利于导电网链的形成,但另一方面对胶合强度有不利影响,进而不利于胶合板的导电性,因此电磁屏蔽性能是这两个方面综合作用的结果.黄铜纤维长度的增加可以使胶层中黄铜纤维的搭接率增加,有利于电磁屏蔽效能的增加.     

Carbon monoxide as a tracer for assessing exposures to particulate matter in wood and gas cookstove households of highland Guatemala

Kitchen-area 22-h gravimetric PM2.5 and passive diffusion stain-tube carbon monoxide (CO) concentrations were measured in homes with open fire and improved wood cookstoves in two studies. In the first study (Guat-2), which also studied homes with gas cookstoves, three samples were collected per stove condition from each of three test houses. In the second study (Guat-3), one sample was collected per house from 15 open fire and 25 improved-stove houses. CO personal samples were also taken for mother and child in both studies. Spearman correlation coefficients (R) between kitchen-area CO and PM2.5 levels in homes using open fires or impoved wood cookstoves were high ranging from 0.92 (Guat-2) to 0.94 (Guat-3), as were those between the personal samples for mother and child ranging from 0.85 (Guat-3) to 0.96 (Guat-2). In general, the correlations were lower for less-polluted conditions. The study found that CO is a good proxy for PM2.5 in homes using open fires or planchas (improved wood cookstove with chimney) but not under gas stove use conditions. It also determined that mother personal CO is a good proxy for child's (under 2 years of age) personal CO and that area CO measurements are not strongly representative of personal CO measurements. These results generally support the use of Draeger CO passive diffusion tubes as a proxy for PM2.5 in such cases where a single type of emission source is the predominant source for CO and PM2.5.     

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.     

海丝纤维吸附铜和锌离子的性能

为研究海丝纤维对铜和锌离子的吸附性能,用氯化铜和硫酸锌水溶液在不同时间、温度等条件下处理海丝纤维,通过测试溶液中铜和锌离子浓度的变化研究海丝纤维对铜和锌离子的吸附量.结果显示:由于纤维结构中分布着富含海藻酸的海藻植物颗粒,海丝纤维对铜和锌离子均有良好的吸附性能,对2种金属离子的平衡吸附量分别约为7和2 mg/g.海丝纤...     

Effect of excessive pretreatment of pine timber with CCA wood preservatives on the bond quality of PRF and TRF wood adhesives

The phenol-resorcinol-formaldehyde adhesive is suitable for use at all levels of CCA retention that were tested. Due to changes in retention during treatment, best results are obtained if the glue-spread rate is kept above the standard of 200 g/m², or control measures are taken to prevent the glue-spread from dropping below this level. The tannin-resorcinol-formaldehyde adhesive, without modification, unlike its performance in the manufacture of plywood, appears from these tests to be less suitable for use on treated timber from the view point of lowered percentage of wood failure.     

Laboratory evaluation of boron-containing quaternary ammonia compound, didecyl dimethyl ammonium tetrafluoroborate (DBF) for control of decay and termite attack and fungal staining of wood

This study evaluates the decay and termite resistance of wood treated with didecyl dimethyl ammonium tetrafluoroborate (DBF), a recently developed quaternary ammonia compound containing boron. Laboratory decay resistance tests were performed using brown-rot fungus, Fomitopsis palustris and white-rot fungus, Trametes versicolor. Treated wood specimens were also subjected a 3-week-termite resistance test using subterranean termites, Coptotermes formosanus. Decay resistance tests showed that wood specimens treated with 0.5 and 1.0% DBF solutions were well protected against both fungi even after a 10-day severe leaching process, suggesting the adequate fixation of DBF in wood. DBF treatment at 0.1% concentration was efficient against subterranean termites, Coptotermes formosanus Shiraki based on mass losses in both leached and unleached wood specimens. The ability of DBF to inhibit discolorations by selected mold and stain fungi was also screened in laboratory conditions. DBF at the highest concentration level (1%) provided limited protection against mold and staining fungi tested, however, it was effective for only short-term protection (1 or 2 weeks) at lower concentrations. These results suggest that DBF is promising to protect wood to be used outdoors against both fungal decay and termite attack however field tests are needed to observe the performance of DBF-treated wood in ground contact.