共查询到19条相似文献，搜索用时 328 毫秒
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用4种热处理方法处理腺瘤豆心材,可有效去除异味,替代珍贵绿柄桑木材使用.处理后的木材经白腐菌侵染 12星期,平均质量损失率与未经处理的试材相比变化不大,天然耐久性等级保持不变,而且其中2种处理方法还能够明显提高木材的耐腐性能,木材的天然耐久性等级因此也由Ⅱ类提高到Ⅰ类. 相似文献
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高温油热处理对竹材淀粉含量及防霉性能的影响 总被引：1，自引：0，他引：1
为了探索高温油热处理改性工艺对5年生新鲜毛竹材淀粉含量及防霉性能的影响,研究采用甲基硅油为加热介质,在不同热处理时间(2,4和6 h)和不同热处理温度(140,160,180和200℃)条件下对毛竹进行高温油热处理。利用分光光度计法测量竹材中的淀粉含量,采用扫描电子显微镜(SEM)观察热处理前后竹材微观结构变化,同时对比了不同油热处理工艺下竹材的防霉效果。试验结果表明:未处理竹材的淀粉含量为3.16%,经过油热处理的竹材淀粉含量均少于未处理竹材,且淀粉含量随着油热处理温度和时间的增加而逐渐降低。在200℃、6 h油热处理条件下,处理后竹材的淀粉含量为0.09%,相比于未处理竹材下降97.23%,高温油热处理能够有效降低竹材中淀粉含量;通过SEM观察发现高温油热处理后竹材薄壁细胞组织发生变形破裂,竹材的渗透性提高,细胞腔中淀粉颗粒显著减少,且竹材纹孔及表面有油介质附着提高防霉性能;在竹材防霉试验中,经过油热处理竹材的防霉能力与未处理材相比均有提高。当热处理温度大于160℃时,防霉效果显著,且竹材淀粉含量越低,对霉菌的防霉效果越好。 相似文献
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八种防霉剂对橡胶木和竹材霉菌及蓝变菌的毒性试验 总被引：3，自引：0，他引：3
霉菌和蓝变菌是橡胶木和竹材变质的主要原因之一。八种防霉荆对上述木竹材霉菌及蓝变菌的毒性试验结果表明：祛霉乐防霉剂对霉菌的最低抑制浓度为２～１０ＰＰｍ，和ＭＥＣＴ相当，对蓝变菌有特效，防治橡胶木或竹材霉菌和蓝变菌的最低有效浓度为０．２％，可替代五氯酚钠和进口防霉剂。 相似文献
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以戊二醛为交联剂制备壳聚糖/聚乙烯醇互穿聚合物,并对其溶胀性进行表征。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和傅里叶变换红外光谱(FT-IR)研究聚合物的微观形貌和化学结构特征。将戊二醛、壳聚糖及聚乙烯醇混合后通过真空浸渍的方式注入竹材中并发生交联反应,测试处理材的干缩湿胀和防霉防腐性能。结果表明:壳聚糖可均匀分散在聚乙烯醇中,成膜均匀,两者相容性较好;处理材在浸水-干燥3次循环下干缩率为6.9%~7.4%,在吸湿-干燥3次循环下的干缩率为1.4%~1.5%,吸水和吸湿抗胀率最高达34.5%;壳聚糖/聚乙烯醇互穿聚合物在竹材中的构建提高了竹材的防霉和防腐效果。未处理材在试验开始后霉菌便迅速长满,处理材霉菌孢子萌发推迟,生长缓慢,处理后竹材经褐腐菌密粘褶菌和白腐菌彩绒革盖菌侵染后的质量损失率为10.0%和5.4%,与未处理材相比分别减少了8.0%和8.1%。竹材内原位构建壳聚糖/聚乙烯醇聚合物网络,既能够提高竹材的尺寸稳定性,又增加了竹材的防霉和防腐性能,同时为解决竹材尺寸稳定性差和易霉变腐朽问题提供新途径。 相似文献
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Heat treatment of wood at relatively high temperatures (in the range of 150–280°C) is an effective method to improve biological
durability of wood. This study was performed to investigate the effect of heat treatment process optimisation on the resistance
against fungal attack, including basidiomycetes, molds and blue stain fungi. An industrially used two-stage heat treatment
method under relatively mild conditions (<200°C) was used to treat the boards. Heat treatment of radiata pine sapwood revealed
a clear improvement of the resistance against the brown rot fungi Coniophora puteana and Poria placenta. Increasing process temperature and/or effective process time during the first process stage, the hydro thermolysis, appeared
to affect the resistance against C. puteana attack, but the effect on the resistance against P. placenta was rather limited. Heat treated radiata pine showed a limited resistance against the white rot fungus Coriolus versicolor and process variations during the hydro thermolysis stage appeared not to affect this resistance. A clear difference between
the resistance of heat treated Scots pine sapwood and heartwood against fungal attack is observed. Scots pine heartwood showed
a higher resistance against C. puteana and P. placenta but also against the white rot fungus C. versicolor. Similar results were obtained when heat treated birch was exposed to brown and white rot fungi. Heat treatment showed an
improved resistance against C. puteana attack, especially at higher temperatures during the hydro thermolysis stage. A clear improvement of the durability was also
observed after exposure to the white rot fungus C. versicolor and especially Stereum hirsutum. Increasing the process temperature or process time during the hydro thermolysis stage appeared to have a limited effect
on the resistance against C. versicolor attack. Heat treated radiata pine and Norway spruce were still susceptible to mold growth on the wood surface, probably due
to the formation of hemicelluloses degradation products (e.g. sugars) during heat treatment. Remarkable is the absence of
blue stain fungi on heat treated wood specimen, also because the abandant blue stain fungi were observed on untreated specimen.
Molecular reasons for the resistance of heat treated wood against fungal attack are discussed in detail contributing to a
better understanding of heat treatment methods. 相似文献
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《Wood material science & engineering》2013,8(2):101-106
Abstract The effect of heat treatment on decay resistance of white birch was evaluated for different incubation periods ranging from 2 to 12 weeks using three species of brown rot and one species of white rot fungus. The results of weight loss tests showed that the white rot fungus, Trametes versicolor, effectively degraded the untreated wood (73.5%). While the degradation of untreated wood by brown rot fungi species, Gloephyllum trabeum (11.6%) and Conifora puteana (6.2%), was considerably less compared to T. versicolor, the third brown rot fungi studied, Poria placenta, caused an appreciable degradation of the same species (52.4%). The results clearly showed that the heat treatment reduced the effect of fungi attack on white birch. Increasing the heat treatment temperature from 195 to 215°C resulted in reduction of weight loss, consequently, reduction in fungal attack. As an example, the weight loss reductions due to T. versicolor, P. placenta, G. trabeum and C. puteana attack was 62.2%, 71.3%, 89.6% and 100%, respectively, compared to the weight loss of untreated wood when it is heat treated at 215°C. Thus, these results confirmed that the heat treatment increased the biological resistance of white birch. 相似文献
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Effect of heat treatment intensity on some conferred properties of different European softwood and hardwood species 总被引：1，自引：0，他引：1
Mounir Chaouch Stéphane Dumarçay Anélie Pétrissans Mathieu Pétrissans Philippe Gérardin 《Wood Science and Technology》2013,47(4):663-673
Effect of heat treatment intensity on some conferred properties like elemental composition, durability, anti-swelling efficiency (ASE) and equilibrium moisture content (EMC) of different European softwood and hardwood species subjected to mild pyrolysis at 230 °C under nitrogen for different durations has been investigated. Independently of the wood species studied, elemental composition is strongly correlated with the mass losses due to thermal degradations which are directly connected to treatment intensity (duration). In all cases, an important increase in the carbon content associated with a decrease in the oxygen content was observed. Heat-treated specimens were exposed to several brown rot fungi, and the weight losses due to fungal degradation were determined after 16 weeks, while effect of wood extractives before and after thermal treatment was investigated on mycelium growth. ASE and EMC were also evaluated. Results indicated important correlations between treatment intensity and all of the wood conferred properties like its elemental composition, durability, ASE or EMC. These results clearly indicated that chemical modifications of wood cell wall polymers are directly responsible for wood decay durability improvement, but also for its improved dimensional stability as well as its reduced capability for water adsorption. All these modifications of wood properties appeared simultaneously and progressively with the increase in treatment intensity depending on treatment duration. At the same time, effect of extractives generated during thermal treatment on Poria placenta growth indicated that these latter ones have no beneficial effect on wood durability. 相似文献
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Anatta Patcharawijit Ram Yamsaengsung Nuttaporn Choodum 《Wood material science & engineering》2020,15(5):261-268
ABSTRACT This research was aimed to investigate mechanical properties, color and cell-wall components changes, and durability of pre-dried rubberwood (Hevea brasiliensis) after superheated steam (SS) treatment. Wood samples were treated at different SS temperatures (140–180°C) for 1–3?h. The highest compression strength parallel-to-grain, hardness and impact strength were found for samples treated at 160°C for 3?h (30.7% higher than untreated), at 150°C for 1?h (26.6% higher than untreated) and at 150°C for 2?h (52.6% higher than untreated), respectively. The surface color became darker after each treatment in comparison with the untreated wood. The number of accessible hydroxyl groups decreased and the relative cellulose crystallinity increased with SS temperature, indicating decreased hygroscopicity of the treated wood. Also, SEM micrographs of wood surface showed consistent decrease in starch particles with treatment temperature. Both decay and termite resistances of treated rubberwood improved with treatment temperature. All the analyzes showed that dried rubberwood treated with SS had some improvements in the mechanical properties, decreased hygroscopicity, and increase resistance to decay. 相似文献
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《Wood material science & engineering》2013,8(3-4):105-114
Abstract Thermal modification has been developed for an industrial method to increase the biological durability and dimensional stability of wood. In this study the effects of thermal modification on resistance against soft- and brown-rot fungi of sapwood and heartwood of Scots pine and Norway spruce were investigated using laboratory test methods. Natural durability against soft-rot microfungi was determined according to CEN/TS 15083-2 (2005) by measuring the mass loss and modulus of elasticity (MOE) loss after an incubation period of 32 weeks. An agar block test was used to determine the resistance to two brown-rot fungi using two exposure periods. In particular, the effect of the temperature of the thermal modification was studied, and the results were compared with results from untreated pine and spruce samples. The decay resistance of reference untreated wood species (Siberian larch, bangkirai, merbau and western red cedar) was also studied in the soft-rot test. On average, the soft-rot and brown-rot tests gave quite similar results. In general, the untreated heartwood of pine was more resistant to decay than the sapwood of pine and the sapwood and heartwood of spruce. Thermal modification increased the biological durability of all samples. The effect of thermal modification seemed to be most effective within pine heartwood. However, very high thermal modification temperature over 230°C was needed to reach resistance against decay comparable with the durability classes of “durable” or “very durable” in the soft-rot test. The brown-rot test gave slightly better durability classes than the soft-rot test. The most durable untreated wood species was merbau, the durability of which could be evaluated as equal to the durability class “moderately durable”. 相似文献
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S. Nami Kartal Christian Brischke Andreas O. Rapp Yuji Imamura 《Wood Science and Technology》2006,40(1):63-71
Evaluation of wood preservatives in soil-contact tests is becoming an important issue since detoxification of wood-protecting
compounds by fungi and bacteria found in soil may decrease the resistance of treated wood. In this study, the decay resistance
of wood treated with didecyl dimethyl ammonium tetrafluoroborate (DBF), a recently developed quaternary ammonia compound,
was evaluated in both soil bed and laboratory decay resistance tests. Small specimens (5×10×100 mm3) of DBF-treated and untreated sugi sapwood were subjected to decay in laboratory soil bed tests (DIN ENV 807 (2001)) followed
by Basidiomycetes tests (DIN EN 113 (1996)). Exposure in field soil and compost soil substrates was used to observe the effects
of wood degrading and other soil-inhabiting micro-organisms on the decay resistance of the specimens. Soil bed tests showed
that DBF-treated wood specimens at 7.7 kg/m3 retention level (1% DBF solution concentration) showed better performance compared to 0.01 and 0.1% DBF treatments. The 7.7 kg/m3 retention level was also effective to protect the wood specimens against Coniophora puteana and Coriolus versicolor in Basidiomycetes tests. It is concluded that detoxification of wood preservatives in soil contact is an important factor
to determine protective properties of treated wood in ground contact applications. Further experiments with larger specimens
are needed to observe the performance of DBF-treated wood at higher retention levels in field above ground and ground contact
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Dedicated to Prof. Dr. H.C. Mult. Walter Liese on the occasion of his 80th birthday. 相似文献