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酚类阻燃剂处理杉木热解过程的热动力学研究 总被引：8，自引：0，他引：8
抗流失阻燃剂是当前阻燃剂研究开发的一个重要方向。采用TG DTA热分析技术研究了酚类阻燃剂处理杉木热解过程各阶段的木炭产量和热动力学参数。结果表明 ,酚类阻燃剂阻燃处理杉木的产炭量因苯环上取代基不同而不同 ,其阻燃作用的大小顺序为 :氨基 >溴 >硝基。同时具有氮元素和溴元素的二溴硝基苯酚和二溴氨基苯酚的产炭量都大于相应的单取代苯酚衍生物。浸泡实验后 ,磷酸氢二铵的产炭损失率是二溴硝基苯酚的 5倍。阻燃处理后产炭量的增大总是对应于炭化阶段热解反应峰温降低、反应速率常数增大 ,但产炭量的增大程度与这些热动力学参数的改变是负相关的。因此 ,氮和溴的苯酚衍生物不仅对木材具有很强的阻燃作用 ,而且具有很强的抗浸泡能力 ,氮元素的阻燃作用与其在阻燃剂中的氧化态关系极大 ,氮和溴在木材阻燃中存在协同增效作用 ,阻燃处理对木材的吸湿性也有影响。 相似文献
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Highly hydrophobic bulk wood was successfully prepared by grafting long-chain octadecyl isocyanate (OTI) onto wood cell walls via a urethane linkage. The resulting wood was highly hydrophobic and showed significantly reduced surface free energy. The microstructure and chemical composition of the untreated and treated wood were characterized using the scanning electron microscopy, energy-dispersive X-ray spectrometry, and Fourier transform infrared spectroscopy. The hydrophobic property of the wood was characterized using contact angle measurements. The mechanical and physical properties as well as the chemical durability of the highly hydrophobic wood were evaluated. The results suggested that the resultant OTI-treated wood presented fairly low surface free energy, high hydrophobicity even in the wood core, and excellent stability and durability against chemical corrosion and mechanical abrasion. Furthermore, the physical properties, including self-cleaning, dimensional stability, and water uptake, were significantly improved in the treated wood. 相似文献
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通过利用各元素之间的协效作用，在二氧化硅表面与氮、磷、硫元素发生接枝共聚制备成氮-磷-硫/二氧化硅（N-P-S/SiO2）复合阻燃剂，用来对竹基板材进行改性处理，研究其对板材的阻燃性能。结果显示，经N-P-S/SiO2复合阻燃剂处理的竹板材载药能力及阻燃性能均优于浸渍N-P-S处理的样品，随着时间的增加竹板材的载药量呈现出先上升后趋于稳定的变化趋势；TG/DTG结果显示，经N-P-S/SiO2复合阻燃剂处理的样品有较高的残炭量（32.1%）及热稳定性。 相似文献
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Impregnation and mechanical properties of three softwoods treated with a new fire retardant chemical
Three softwoods, Sugi (Cryptomeria japonica), Korean Pine (Pinus koraiensis) and Hinoki (Chamaecyparis obtusa), were vacuum–pressure impregnated with a fire retardant chemical consisting of ammonium phosphate polymer (APP), guanyl urea phosphate (GUP), phosphonic acid and a minor amount of additives. The variation in impregnation between and within wood species was investigated. A significant relationship and similar trends were found between fire retardant chemical (FR) uptake and specific gravity (SG), as well as void volume filled (VVF) and SG. Moreover, the effects of fire retardant treatment on mechanical properties, including modulus of rupture (MOR), static modulus of elasticity (MOE) and dynamic modulus of elasticity (DMOE), were evaluated. The results indicated that the trend of impregnation and regression function varied between species and positions within the same species. However, the relationship of SG and chemical uptake and that of VVF and chemical uptake could be represented by a positive linear regression, and the trends were similar between wood species. Both of SG and VVF increased with increasing FR uptake. After fire retardant treatment, the MOR and static MOE were reduced compared with before treatment. Conversely, the DMOE increased after treatment. 相似文献
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Modification of three hardwoods with an N-methylol melamine compound and a metal-complex dye 总被引：1，自引：0，他引：1
Bodo Caspar Kielmann Stergios Adamopoulos Holger Militz Gerald Koch Carsten Mai 《Wood Science and Technology》2014,48(1):123-136
This study evaluated the combined modification and staining of ash, beech and maple wood with a low molecular weight N-methylol melamine compound (NMM) and a metal-complex dye. Wood samples were treated with aqueous solutions of 10, 20 and 30 wt% NMM and 5 wt% of the dye. The treatment caused the fixation of the water-soluble dye by the NMM resin. Vacuum pressure impregnation of unsealed wood blocks did not result in different solution uptake and weight percent gain after curing among the three species, but sealing of the surfaces of the wood blocks to allow penetration only into one direction revealed easiest penetrability of beech followed by maple and ash. UV micro-spectrophotometry and light microscopy indicated that NMM was partly deposited in the cell wall and partly in the lumens. Penetration of the metal-complex dye was shown by means of X-ray micro-analysis (SEM–EDX). The study shows that a combined resin modification and staining of the three wood species tested is possible and that NMM causes fixation of the water-soluble dye. 相似文献
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Minzhen Bao Xianai Huang Mingliang Jiang Neng Li Yanglun Yu Wenji Yu 《Journal of Wood Science》2018,64(3):264-278
The effects of high temperature, moisture, and mechanical action during the thermo-hydro-mechanical (THM) processing, on the changes in surface properties of poplar, namely, surface color, roughness, wettability, and microstructure, were investigated in this study. The correlation between observed changes in surface properties and chemical characteristics was also analyzed. Poplar woods with high moisture content were compressed using different pressures at temperature of 160 °C for four different periods. The wood surfaces became darker and smoother, and their surface free energy decreased significantly after the THM process. THM process markedly reduced surface hygroscopicity compared to the control wood. The cell lumens of THM wood became narrow with increasing compression ratio due to the enhancing high pressure. Collapse and fractures of cell walls developed during THM treatment. Furthermore, results indicated that a series of chemical reactions in different components of wood took place during THM process, such as degradation of hemicelluloses, condensation of lignin, and decomposition of extractives. In turn, these chemical modifications contributed to the darkening of color as well as the reduction of wettability and surface free energy of THM wood. 相似文献
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利用锥形量热仪CONE对不同热处理工艺下的杨木燃烧行为进行研究。结果表明:热处理后杨木中亲水的羟基、羰基数量明显减少,大量半纤维素降解。木材试样从外部热源引燃到燃烧结束,出现两个主要放热峰。热处理后杨木引燃和燃烧过程的发烟量较大,且热处理杨木引燃时间更短。热处理材的热释放峰值pk-HRR、平均热释放速率av-HRR和总热释放量THR均低于未处理材,表明其燃烧强度低于未处理材。热处理杨木燃烧过程的总烟释放量TSP较未处理材有所增加,同时其引燃时间也有所缩短。因此,对用于家具和室内装饰的热处理木材,建议进行恰当的阻燃处理。 相似文献
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Cao Jin-zhen Li Li-dan Liu Zhi College of Materials Science Engineering Beijing Forestry University Beijing P. R. China 《中国林学(英文版)》2005,7(4)
In this study, the contact angles of three different reference liquids (including distilled water, diiodomethane, and formamide) and PF resin on the surfaces of Chinese fir (Cunninghamia lanceolata) samples untreated or treated with different con- centrations of ACQ-D (ammoniacal copper quat Type D) solutions were measured. Then, the surface free energy was calculated by two approaches: acid-base approach and geometric mean approach. ACQ-D treatment caused higher contact angles and lower surface free energies at a retention level corresponding to the commodity treated wood products. When wood was treated with much higher concentrations of ACQ-D, the total surface free energy of wood would be higher than the untreated control. Acid-base/polar compo- nents related with the hydrogen bonding state in wood were considered to be responsible for the observed changes according to the applied approaches. The hydrophobic properties and also higher contact angles of PF resin drop on wood surfaces after ACQ-D treatment at a reasonable retention level confirms the changes on surface free energy. 相似文献
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以聚乙烯亚胺(PEI)为改性剂处理聚磷酸铵(APP)制备得到APP@PEI阻燃体系,并将其加入到脲醛树脂(UF)中,制备阻燃胶合板。研究了APP@PEI对UF胶黏剂理化性能的影响,并进一步探讨其对胶合性能及阻燃性能的影响。结果表明:APP、PEI和APP@PEI对UF的黏度、pH和固化时间均有影响。当APP添加量为10%时,UF的黏度由3.843 Pa·s上升至8.270 Pa·s,pH降至5.67,固化时间由91 s降至87 s;当PEI添加量为0.91%时,由于UF体系中支化和交联程度增加,黏度上升至41.433 Pa·s,pH和固化时间分别提升至9.91和116.3 s;而APP@PEI能降低对UF各项性能的影响,添加10%APP@PEI时UF的黏度、pH和固化时间分别为5.966 Pa·s、6.33和94.3 s。添加APP后,胶合板的胶合强度均低于Ⅱ类胶合板强度标准(0.7 MPa);添加PEI后,胶合板的胶合强度能够提升18%以上;APP@PEI添加量为10%时,胶合板的胶合强度达0.85 MPa,高于Ⅱ类胶合板强度标准要求。添加APP、PEI和APP@PEI对胶合板的阻燃性能有不同影响,单独添加PEI无法改善胶合板的阻燃性能,当APP和APP@PEI添加量为10%,15%和20%时,胶合板的极限氧指数(LOI)分别比未添加阻燃剂时提高0.8%,2.0%,2.5%和1.2%,2.2%,3.1%。 相似文献
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Chemical mechanism of fire retardance of boric acid on wood 总被引：5，自引：0，他引：5
It is commonly accepted that the fire retardant mechanism of boric acid is a physical mechanism achieved by the formation of a coating or protective layer on the wood surface at high temperature. Although a char-forming catalytic mechanism has been proposed by some researchers, little direct experimental support has been provided for such a chemical mechanism. In this paper, new experimental results using thermal analysis, cone calorimetry (CONE), and gas chromatography–Fourier transform infrared spectroscopy (GC–FTIR) analysis are presented and the fire retardant mechanism of boric acid on wood is discussed. Basswood was treated with boric acid, guanylurea phosphate (GUP), and GUP–boric acid. Treated wood was then analyzed by thermogravimetry (TG/DTG), differential thermal analysis (DTA), CONE, and GC–FTIR analysis. Thermogravimetry showed that the weight loss of basswood treated with boric acid was about three times that of untreated or GUP-treated wood at 165°C, a temperature at which GUP is stable. The DTA curve showed that boric acid treated basswood has an exothermal peak at 420°C, indicating the exothermal polymerization reaction of charring. CONE results showed that boric acid and GUP had a considerable synergistic fire retardant effect on wood. The GC–FTIR spectra indicated that compounds generated by boric acid treated wood are different than those generated by untreated wood. We conclude that boric acid catalyzes the dehydration and other oxygen-eliminating reactions of wood at a relatively low temperature (approximately 100–300°C) and may catalyze the isomerization of the newly formed polymeric materials by forming aromatic structures. This contributes partly to the effects of boric acid on promoting the charring and fire retardation of wood. The mechanism of the strong fire retardant synergism between boric acid and GUP is due to the different fire retardant mechanisms of boric acid and GUP and the different activation temperatures of these two chemicals.The Forest Products Laboratory is maintained in cooperation with the University of Wisconsin. This article was written and prepared by U.S. Government employees on official time, and it is therefore in the public domain and not subject to copyright. The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service. 相似文献
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考察了三乙醇胺(TEM)对3种木材阻燃剂(F1、F2、DPB)处理试件的载药率、阻燃效果、吸湿性的影响。试验结果表明:随三乙醇胺加入量的增加,阻燃试件的载药率增加,氧指数增加,阻燃效果得到改善;三乙醇胺加入量大于3.5%时,处理液的黏度增加,载药率增加不明显;加入2.5%～3.5%的三乙醇胺时,处理试件的吸湿率最小。同时实验还显示了在3种木材阻燃剂中加入三乙醇胺后,只有F2与三乙醇胺有协同效应,其它两种阻燃剂协同效应不明显。 相似文献
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Shan He Yichen Guo Tehila Stone Noah Davis Dongwhan Kim Taejin Kim Miriam Rafailovich 《Journal of Wood Science》2017,63(2):154-160
A wood-plastic combination (WPC) was created via in situ polymerization of the l-lactide monomer (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione. Commercial poplar boards (Liriodendron tulipifera) were impregnated with the flame retardant chemical resorcinol bis(diphenyl phosphate)(RDP). These samples were then soaked in a solution of the monomer and deionized water with sulfuric acid 5% wt/wood as a catalyst for polymerization. The wood and solution were placed in a vacuum oven for impregnation and polymerization of the monomers. The wood RDP combination was not flame retardant and had an Izod impact strength that was slightly smaller than neat wood sample. Addition of lactide monomer tripled the Izod impact strength relative to wood, and scanning electron microscope (SEM) images indicated that a polymerized coating had formed which reinforced the porous wood structure. Addition of all three components produced a synergy. The Izod impact strength of the material was nearly 14 times greater and the WPC was flame retardant surpassing the stringent UL-94-V0 requirement. 相似文献
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Cao Jin-zhen Li Li-dan Liu Zhi 《中国林学(英文版)》2005,7(4):29-34
In this study, the contact angles of three different reference liquids （including distilled water, diiodomethane, and formamide） and PF resin on the surfaces of Chinese fir （Cunningharnia lanceolata） samples untreated or treated with different concentrations of ACQ-D （ammoniacal copper quat Type D） solutions were measured. Then, the surface free energy was calculated by two approaches： acid-base approach and geometric mean approach. ACQ-D treatment caused higher contact angles and lower surface free energies at a retention level corresponding to the commodity treated wood products. When wood was treated with much higher concentrations of ACQ-D, the total surface free energy of wood would be higher than the untreated control. Acid-base/polar components related with the hydrogen bonding state in wood were considered to be responsible for the observed changes according to the applied approaches. The hydrophobic properties and also higher contact angles of PF resin drop on wood surfaces after ACQ-D treatment at a reasonable retention level confirms the changes on surface free energy. 相似文献
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通过处理三组不同密度的水曲柳,对比研究了BL-环保阻燃剂和市场上两种木材阻燃剂的渗透性及阻燃性等。结果表明,BL-环保阻燃剂在阻燃性、抑烟性方面优于另外两种阻燃剂;在渗透性和吸湿性方面居中;而在对木材力学性能的影响方面不如其他两种阻燃剂。 相似文献
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蒸汽介质热处理对毛白杨木材颜色的影响 总被引：2，自引：0，他引：2
以毛白杨木材为研究对象,采用蒸汽介质热处理方法在氧气含量低于2%的密闭容器中以温度170～230℃、时间1～5h的处理条件对其进行热处理。结果表明:随着处理温度的升高和处理时间的延长,色饱和度差ΔC*逐渐减小、色差ΔE*和色相差ΔH*逐渐增大,说明热处理后木材的颜色由原色逐步过渡到深褐色。方差分析和多重比较结果表明:热处理温度比热处理时间对毛白杨木材颜色变化的影响更为重要。此外,进一步得出了色差值与热处理温度、时间三者之间的回归模型。利用此特性,对一些浅色木材进行热处理,可赋予其凝重的颜色,同时还可增强其尺寸稳定性,从而提高其产品附加值,扩大应用领域。 相似文献
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