微波超声波技术在阻燃剂浸渍处理木材中的应用

将微波处理与超声波辐射技术应用于木材阻燃处理中,利用微波加热处理改善木材构造的渗透性能,利用超声波的空化作用强化阻燃剂浸入性能。以ZR—M-301型木材阻燃剂为浸渍药液,樟子松和水曲柳为木材试样,选择常压浸渍、压力浸渍和微波处理后超声波加压浸渍3种木材阻燃处理方法,考察在生产阻燃木材的浸渍方法中引入微波和超声波技术的可行性,实验表明新的技术路线是可行的。     

木材构造对木材化学阻燃浸渍处理方法的影响

从木材构造对化学阻燃浸渍处理工艺影响的角度,指出在木材化学阻燃浸渍处理过程中,影响阻燃剂在木材中渗透性的木材主要微观构造有浸提物、纹孔等,分析了木材中水分的存在状态和木材中水分的移动与木材化学阻燃浸渍处理工艺的关系。探讨了强化木材化学阻燃浸渍处理的方法。采用微波技术提高木材的渗透性,采用超声波技术强化阻燃剂的浸渍。实验表明是一条可行的技术路线。     

木材阻燃研究及发展趋势

近年,随着我国阻燃法规的建立健全,阻燃技术的不断发展,新型的木材阻燃剂及阻燃技术不断涌现。阐述了木材的化学组成及燃烧过程、木材阻燃剂类型、阻燃机理、木材阻燃处理方法及各种处理方法的优缺点,同时介绍了国内外木材阻燃研究的发展方向,对我国木材阻燃剂工业进一步发展提出了建议。木材阻燃的发展趋势是开发一剂多效的新型复合阻燃剂,同时深入探索阻燃机理,为组合新的阻燃体系提供有效的途径,使木材阻燃研究与市场实际需求相结合,为生产实践的应用提供了理论基础。     

阻燃剂在建筑材料中的应用进展

介绍了阻燃剂的种类及阻燃机理,结合绿色环保理念,探讨它在建筑材料中的防火应用。钢材防火以涂饰阻燃涂料为主,电线电缆及工程塑料的阻燃可以采用涂饰阻燃材料和添加阻燃成分改性,木材的阻燃则采用浸渍法,纸质的阻燃则采用浸渍法和添加阻燃成分法。综述了各类阻燃剂在这些建筑材料中的应用情况,展望了阻燃剂在建筑材料中的应用前景和发展趋势。     

P—N复合木材阻燃剂的研制

以磷－氮阻燃剂为基础，根据协同效应，添加了其它阻燃剂和高效渗透剂，并采用均匀设计试验及最优化处理方法，对该阻燃剂的配方及浸渍工艺进行了研究，制成复合阻燃剂，处理后的木材阻燃性能达到规定的阻燃标准。     

P—N复合木材阻燃剂的研制

以磷－氮阻燃剂为基础，根据协同效应，添加了其它阻燃剂和高效渗透剂，并采用均匀设计试验及最优化处理方法，对该阻燃剂的配方及浸渍工艺进行了研究，制成复合阻燃剂，处理后的木材阻燃性能达到规定的阻燃标准。     

地板木阻燃技术及其应用

介绍了木材阻燃机理，处理方法及阻燃剂组分。开发了阻燃拼花地板木新产品取得较显著的经济效益。     

聚氨酯泡沫塑料的阻燃

简要介绍了对多孔性材料聚氨酯泡沫塑料进行阻燃处理的重要性，并对各类阻燃剂的阻燃机理以及聚氨酯泡沫塑料阻燃研究领域的技术进展进行了介绍。较全面地综述了改善软质和硬质聚氨酯泡沫塑料阻燃性能的方法，包括：各种添加型阻燃剂和反应型阻燃剂的特点及使用效果，不同阻燃剂的协同作用，引入异氰脲酸酯基团提高硬泡阻燃性能，采用阻燃剂溶液浸渍开孔泡沫塑料等。     

木材阻燃处理工艺研究

研究了一种磷氮系阻燃剂的最佳阻燃处理工艺。由双氰胺、甲醛、尿素、磷酸二氢铵按一定比例配成阻燃液,经两次浸渍处理、高温聚合获得阻燃木。采用正交实验探讨了各种因素的影响,测定了阻燃木材的阻燃性能。较优的阻燃处理工艺是一次浸渍液的质量分数为１５％ ,ｐＨ＝ １１,时间为２４ ｈ,１１０ ℃烘干６ ｈ;二次浸渍液的质量分数为２０％ ,时间为１４ ｈ。此条件下经火管法测试为阻燃一级。     

硅酸盐阻燃木材的阻燃性能和热性能研究

通过二次浸渍工艺获得了硅酸盐阻燃木材样品,通过极限氧指数(LOI)测试了样品的阻燃性能,通过热分析结合扫描电子显微镜(SEM)研究了样品的热降解过程。结果表明:通过二次浸渍工艺可获得阻燃性能优良的阻燃木材,过渡金属硅酸盐可有效的催化木材第二阶段的降解反应,促进炭的生成,还可以在高温下形成熔体覆盖在剩炭的表面,有效提高剩炭的稳定性,同时隔绝可燃性气体的逸出,避免热量和O2的进入,使木材具有良好的阻燃性能。     

硅烷偶联剂处理木塑复合材胶接接头的耐水性

利用硅烷偶联剂KH560对木粉/聚乙烯复合材料进行表面处理以改善其胶接性能。利用接触角、吸水量、表面形貌以及胶接强度测试等分析方法,研究了硅烷偶联剂处理聚乙烯木塑复合材料胶接接头在水环境中的胶接耐久性能。试验结果表明,机械打磨并偶联剂处理后,聚乙烯木塑复合材表面接触角增加,表面粗糙度增大,胶接强度和耐水性明显提高。偶联剂分子链上环氧基团的"架桥"作用以及甲氧基的憎水作用,是粘接强度和耐水性能提高的主要原因。浸水环境下,聚乙烯木塑复合材料表面粗糙度略有降低;随着浸水时间的延长,表面接触角下降,胶接接头的吸水量增加,胶接强度下降。水环境下聚乙烯木塑复合材料中木质纤维成分的吸水膨胀,是造成胶接强度下降的主要原因。     

Reducing the moisture sensitivity of linear friction welded birch (Betula pendula L.) wood through thermal modification

Linear friction welding of wood is a bonding process applied to wood and during which a stiff bond line is formed by the softening and rehardening of wood components to form a composite material composed mainly of wood fibres embedded in a modified lignin matrix. Unfortunately, the bonds tend to spontaneously delaminate or lose their strength when exposed to moist conditions. Some approaches were previously applied to overcome this problem, but so far a suitable solution has not been found. This paper presents results of applying post-welding thermal modification to reduce the moisture sensitivity of welded wood. The experiments included welding of birch wood, thermal modification under superheated steam at atmospheric pressure, internal bond (IB) and tensile-shear strength testing and soaking tests. As supposed, the non-modified reference specimens performed poorly after the seven days soaking test (on average 0.33 MPa IB strength), whereas the thermally modified specimens yielded almost the same IB strength in dry and wet condition (on average e.g. 1.15 and 0.93 MPa, respectively). Such a similar load bearing capacity in very different moisture conditions was previously reported only in the case of paduk wood. Similar to the reduction of IB strength occurred during the soaking test, also delamination was observed more clearly in non-modified reference specimens (e.g. 4 vs. 0 total delaminations after seven days soaking). Therefore, the authors suggest that post-welding thermal modification could provide a suitable bond-stabilisation method against moisture, although the process parameters must be optimised in further research, for instance, to ensure scalability.     

Influence of carbonization conditions on the gasification of acacia and eucalyptus wood chars by carbon dioxide

Gasification rates of cubic shaped acacia and eucalyptus wood chars were measured thermogravimetrically in a carbon dioxide atmosphere at temperatures in the range 810–960 °C. The effects of wood species and carbonization conditions, such as temperature, heating rate and soaking time, were determined. Both reactivity and the activation energy for the gasification of wood chars were found to be strongly influenced by the carbonization conditions employed during their preparation and wood type. The reactivities of both the acacia and eucalyptus wood chars decreased with increasing preparation temperature; while the activation energy for their gasification increased. Slow carbonization (heating rate: 4 °C min⁻¹) led to the production of wood chars having lower reactivities and higher activation energies than those of the wood chars prepared under rapid carbonization (heating rate: 30 °C min⁻¹) at the same temperature. With increasing soaking time, at carbonization temperatures of 800 and 1000 °C, the reactivity of resulting wood chars was reduced. The results also show that the reactivities of acacia wood chars are higher than those of similarly prepared eucalyptus wood chars.     

Influence of carbonization conditions and wood species on carbon dioxide reactivity of resultant wood char powder

Carbon dioxide reactivities of powdered samples of Acacia and Eucalyptus wood chars were measured thermogravimetrically at 900°C and the effects of carbonization conditions (temperature, heating rate and soaking time) and wood species were determined. The results showed that the reactivity decreased with increasing carbonization temperature and soaking time. Chars prepared under rapid carbonization (heating rate: 30°C min⁻¹) were found to be more reactive than the chars produced by slow carbonization (heating rate: 4°C min⁻¹). In comparison to Eucalyptus wood chars, the Acacia wood chars exhibited higher reactivity.     

水对液相氧化处理聚乙烯木塑复合材胶接性能的影响

采用液相氧化方法对木粉/聚乙烯木塑复合材料进行表面处理以改善其胶接性能。研究了氧化处理后木塑复合材料胶接接头的耐水性,并利用接触角测试、SEM、FT-IR等分析手段,探讨了木塑复合材料胶接接头在水环境下的老化失效原因。结果表明,未处理的聚乙烯木塑复合材料难以胶接,经过液相氧化处理后,不但可以提高聚乙烯木塑复合材料的胶接强度,还可改善木塑复合材料胶接接头的耐水性。在水的作用下,液相氧化处理聚乙烯木塑复合材的表面结构会发生改变,复合材料中木质纤维的吸水膨胀也会导致材料表面出现裂纹,致使胶接接头失效。     

Adhesive properties of water-washed cottonseed meal on four types of wood

The interest in natural product-based wood adhesives has been steadily increasing due to the environmental and sustainable concerns of petroleum-based adhesives. In this work, we reported our research on the utilization of water-washed cottonseed meal (WCM) as wood adhesives. The adhesive strength and water resistance of WCM adhesive preparations on poplar, Douglas fir, walnut, and white oak wood veneers were tested with press temperatures of 80, 100, and 130 °C. Our data indicated that raising the hot press temperature from 80 to 100–130 °C greatly increased the bonding strength and water resistance of the WCM adhesives. The general trend of the adhesive strength of WCM on the four wood species was Douglas fir > poplar ≈ white oak > walnut. The rough surface of Douglas fir with tipping features could enhance the mechanical interlocking between the wood fibers and adhesive slurry, contributing to the high adhesive strength. The dimensional swelling of the bonded wood pairs due to water soaking was in the order: thickness > width (i.e. perpendicular to the wood grain) > length (i.e. parallel to the wood grain). The greatest dimensional changes were observed in Douglas fir specimens. However, the highest decrease in adhesive strength by water soaking was with poplar wood specimens. These observations suggested that the wood dimensional changes were not dominant factors on water weakening the bonding strength of these wood pairs.     

木塑复合材料成型工艺及影响因素的研究

论述了木塑复合材料的成型工艺,着重对影响木塑复合材料挤出成型性能的因素如成型设备、工艺条件、基体树脂种类、木粉含量及木粉粒径、添加剂等进行了相应的分析,为深入开展木塑复合材料的加工研究提供了分析资料。