【作者】 楼超超；

【导师】 钱晓倩； 赖俊英；

【作者基本信息】 浙江大学 ， 结构工程， 2010， 硕士

【摘要】 木材作为一种天然资源,具有环保、可再生、美观、力学性能出色等特性,如今在建筑行业正重新得到人们的关注。我国对天然林资源的保护越来越重视,使得速生人工林木材在人造板、门窗、家具等行业所占比重不断提升。木材最重要的缺点之一就是易着火燃烧,因此对速生木材的阻燃处理具有重大的意义。目前主要的阻燃剂可分为有机阻燃剂、无机阻燃剂和树脂型阻燃剂几大类。有机阻燃剂阻燃效率较高,不过价格昂贵,且燃烧时释放有毒气体。无机阻燃剂无毒无害,但阻燃效率相对较低,抗流失性能差。树脂型阻燃剂采用树脂与无机阻燃剂的复合改善了其抗流失性能,国内刚投入工业化生产,应用还不成熟。阻燃剂的研究将朝着低毒抑烟、复合高效、纳米化的方向发展。国内外有学者采用硅溶胶处理木材,邱坚等人有关紫椴、桤木的研究表明,相比素材,木材/SiO₂气凝胶复合材阻燃性能大有提高。总的说来,目前国内外关于硅溶胶作为阻燃剂处理木材的研究报道很少。在本研究的实验中,针对我国南方最主要的速生人工林树种杉木,采用成品硅溶胶（SiO₂溶胶）对其进行浸渍处理,干燥得到木材/SiO₂干凝胶复合材。研究了在较低压力下（0.5MPa以下）,浸渍时间、压力、种内材质差异及试件初始含水率等因素对浸渍效果的影响;采用锥形量热仪对杉木试件进行燃烧试验,分析硅溶胶改性处理对杉木阻燃性能的影响;对处理试件进行力学性能、防腐蚀性能、尺寸稳定性、吸湿性、抗浸提值等方面的测试,更综合地评价阻燃改性处理对木材性能的影响。研究结果:1)随着浸渍时间增加,载药率和浸渍深度增加,4h后变化不明显,0.5h为较合适的浸渍时间;同种木材,试样的材质差异也会显著地影响浸渍处理效果;0.5MPa以下浸渍压力的试验表明:压力对浸渍效果影响明显,同时间载药率随着压力增大明显增加;浸渍处理时,木材试件初始含水率若低于气干含水率（14%-17%）,则对浸渍效果影响很小。2)电子显微镜扫描结果表明:改性处理后木材内部基本结构未发生改变,硅溶胶对木材细胞壁和细胞腔有所填充,在导管内连续分布。3)采用锥形量热仪的燃烧试验表明硅溶胶的改性处理可以较为显著地改善杉木的阻燃性能;改性木材在力学性能、防腐蚀、尺寸稳定性等方面略有提升,略有提升;改性剂硅溶胶具有非常好的抗流失性能。更多还原

【Abstract】 As a natural resource, wood is environmentally friendly, renewable, beautiful, and with excellent mechanical properties .And now it has regained people’s attention in construction industry. In our country, natural wood resources are increasingly protected, so fast-growing plantations, as the replacements, have been playing an increasingly important role in the industries of wood-based panels, doors and windows, furniture, etc. For the wood is an easily ignited material, fire-retarding treatments of the fast-growing plantations is of great significance.At present, wood retardants can be classified into three main categories as organic retardant, inorganic retardant and resin-based flame retardants. Organic retardants can provide good fire-resisting properties, while they are expensive, and release toxic gases while burning. Inorganic retardants are non-toxic, while with poor performances on anti-loss and relatively low fire-resisting efficiency. As to the resin-based retardants, they work together with inorganic retardant, and can highly enhance the anti-loss performance, this kind of retardants have just been put into industrial production. Studies will be focused on developing retardants with the properties of low toxicity and smoke suppression, high fire-resisting, using nano-technology. Scholars at home and abroad tried to modify wood’s property with sol. Studies on Purple linden and alder by Qiujian found that, compared to the material, wood / SiO2 aerogels composite materials have a much better fire-resisting property. In general, there are few reports about treating wood with sol as a retardant.In the experiments of the study, finished sol is used for impregnating fir, the most important fast-growing artificial fir tree in south China. And we get Wood / SiO2 xerogel composite materials after drying. Influence on impregnation effects of the these factors, such as soaking time, pressure, material difference and initial moisture content of samples, are studied. Wood samples are taken combustion tests to analyze the modification of fire retardant by the treatment of silica sol; A more comprehensive evaluation of wood treatment with silica sol is made by taking more tests on mechanical properties, anti-corrosion, dimensional stability, moisture absorption and anti-extraction value of the samples.Study results show that:1)according to 0.5～4h drug-loading rates, drug-loading rate and the depth of drug-loading increase over time, and 0.5h is relatively a suitable soaking time; material differences of samples from the same species of wood can significantly affect the treatment results; soaking experiments with pressure under 0.5MPa show that, soaking pressure has an obvious effect on the impregnation, drug-loading rate increase significantly with pressure; the initial moisture content of the samples, if it is under the air-dry moisture content (14% -17%),will have little effect on the final the drug-loading rate.2) SEM results show that, basic structure of wood does not change after the modification, inside wood cell walls and cell cavities and conduits are filled by sol.3) Tests by Cone Calorimeter shows that the modification of silica sol apparently improves the fire-retardant performance of the wood. In terms of mechanical properties, corrosion protection, moisture absorption and dimensional stability, it has only a slight role of enhancement; Samples modified by silica sol owns a perfect Anti-loss performance.更多还原