桉木防腐的初步研究

以赤桉边材为试件,采用六种防腐剂,经加压浸注法对试件进行防腐处理,检验防腐剂的防腐效果,并且对用两种季铵盐防腐剂处理过的木材进行了抗流失实验。结果表明,当季铵盐-1、酸性铬酸铜(ACC)、铜铬硼(CCB)的药剂保持量为5,7.5,8.3 kg/m3时,经木腐菌腐朽后,试样的质量损失率分别为0.66%,0.59%和0.47%,有较好的耐腐效果。而且通过抗流失性实验发现,两种季铵盐与木材作用后,对水较为稳定,即两者的抗流失性能较好。     

硅烷偶联剂对阻燃处理杨木的防水阻燃性能影响

为了改善氮磷为主成分的BL阻燃剂易吸湿性缺陷,本文采用硅烷偶联剂CG-N1613(十六烷基三甲氧基硅烷)对阻燃处理试件进行二次浸渍处理,同时对比石蜡乳液浸渍、表面涂覆清漆处理以及对素材进行混合浸渍(阻燃剂与石蜡乳液的复配混合液),对处理材的防水性能(吸湿性、表面润湿性、抗流失性)和阻燃性能(氧指数LOI、烟密度等级SDR)进行了评估,探究出较优的处理方法.实验表明,BL阻燃剂处理试件的吸湿率为14.58％,二次浸渍硅烷偶联剂的试件吸湿率降低为12.05％,接触角高达133.94°,抗浸提值LRV由-2.11％提升到41.73％,氧指数LOI由32.2％提高到40.5％;最大烟密度值与仅BL阻燃剂处理基本相同,烟密度等级SDR均小于75.二次浸渍硅烷偶联剂的试件不仅防水效果明显提高,并且在一定程度上保持并提高了其阻燃效果.     

利用低温等离子体对PET工业长丝的表面改性

应用外部电容耦合式低温等离子体处理装置．在不同处理条件下，对PET工业长丝进行表面改性。并通过失重、回潮率和染色实验等方法，研究了处理前后样品的吸湿性、染色性等的变化。结果表明，处理后样品的吸湿性有较大提高，可达到未处理样品的2倍；经处理后的涤纶纤维对分散性染料的染色有一定的改善作用；处理后样品的失重随处理时间的延长而增加，而其强度几乎无变化。     

PVA纤维增强水泥基复合材料高温性能研究

对PVA纤维增强水泥基复合材料的高温性能进行研究,分别测试了该材料在经受不同高温后的质量损失、抗压强度以及弯曲韧性,并对其微观结构变化进行了分析.结果表明,相比于普通水泥基材料,PVA纤维增强水泥基复合材料的抗压强度高,变形能力大,抗折强度高,弯曲韧性优越,其中纤维掺量为2％的试块28 d抗压强度达到45.98 MPa,抗折强度可达到14.10 MPa,最大挠度达到0.68 mm;高温处理后掺有PVA纤维的试块完整性良好,没有出现破坏性断裂,只表现为微小裂纹;随着温度的升高,不同纤维掺量砂浆试块的质量损失增大,抗压强度和抗折强度以一定的速率下降,但在800 ℃高温处理后试块仍具有一定的抗压强度和弯曲韧性,纤维掺量为2％的试块的抗压强度能达到18.9 MPa,最大挠度可保持在0.12 mm;根据微观测试可以看出,随着温度的升高,纤维缓慢熔出使试块内部出现相互交错的孔隙通道可有效防止试块高温爆裂,试块内部结构由致密变为松散蜂窝状.     

新型木材阻燃剂FRW

新型木材阻燃剂FRW是一种具有阻燃、抑烟、防腐等多种效能的磷-氮-硼复合高效阻燃剂,适用于木材及其他纤维素类材料的阻燃处理,对木材的颜色、吸湿性、物理力学和加工性能基本无影响,在生产和使用过程中无环境污染。阻燃剂FRW的制备方法是由双氰胺和磷酸反应合成高纯度脒基脲磷酸盐(GUP),将GUP与硼酸和助剂复配得到产品。     

廉价水溶性N—P阻燃剂的应用

由尿素和磷酸在较低温度下制得之阻燃剂,价格低廉。用它处理的各种可燃性物质,如纸、棉织物、木材、腈纶织物等,都达到了良好的阻燃效果。对纯棉织物如帆布,配以羟甲基三聚氰胺,并采用二焙固整理工艺,可获耐久阻燃性。该阻燃剂还可用于预防和迅速扑灭火灾,且具有不复燃性。     

酚醛树脂/K2CO3复合阻燃剂对木材的阻燃处理及热性能研究

通过对极限氧指数(LOI)的测定,研究了阻燃剂K2CO3、酚醛树脂、三聚氰胺改性酚醛树脂及K2CO3与树脂复合阻燃剂对木材的阻燃性的影响,探讨了阻燃剂的耐水性及抗流失性能.通过热重(TG)、差热分析(DTA)、微分热重分析(DTG)测试研究了阻燃剂对木材的热性能影响.结果表明:经K2CO3和三聚氰胺改性酚醛树脂复合处理...     

低温等离子体对涤纶拉伸丝表面改性的研究

应用外部电容耦合式低温等离子体处理装置,在不同处理条件下,对涤纶拉伸丝进行表面改性,并通过失重、回潮率和染色实验等方法,研究了处理前后样品的吸湿性、染色性等的变化.结果表明,处理后样品的吸湿性有较大提高,可达到未处理样品的2.7倍;经处理后的涤纶纤维对分散性染料的上染率有一定的提高;处理后样品的失重随处理时间的延长而增加,而其取向度几乎无变化.     

低溴阻燃ABS材料的力学性能和阻燃性能

本文采用十溴联苯醚（ＤＢＤＰＯ）和三氧化二锑（Ｓｂ２Ｏ３）阻燃ＡＢＳ,并分别用磷酸酯、钛酸酯、硅烷等偶联剂对阻燃剂进行表面处理,发现随着阻燃剂用量的增加,复合物的阻燃性能逐渐提高,当溴比达到１０％时,材料在空气中点不燃;在提高阻燃性能的同时,材料的力学性能有所下降,尤其是冲击强度下降较明显。将阻燃剂用偶联剂处理后,材料的力学性能得到改善。本文还采用了母料法制备复合物,实验结果表明,采用母料法可进一步改善阻燃剂的分散性,材料的力学性能和阻燃性能都较好     

UF原位聚合改性对速生杨物理性能的影响

速生北京杨用不同摩尔比的甲醛-尿素混合液真空浸渍,应用原位聚合反应制备杨木/脲醛树脂预聚体改性材,测定改性前后速生杨的抗弯强度、抗弯弹性模量、吸水性、吸湿性、增重率等物理性质,采用FTIR、XRD分析结构。结果表明,杨木改性材相比于杨木素材,甲醛/尿素摩尔比1.1时综合性能最优,其增重率为58.80%,抗弯强度提高了22.65%,抗弯弹性模量提高了77.03%,吸水率降低了1.12倍,体积抗吸湿膨胀率为32.92%,抗吸湿率为29.83%。红外及X射线衍射显示甲醛与尿素原位聚合后生成了羟甲基缩聚物,并且与木材中的官能团发生化学交联,且改性后木材结晶度增大。     

Assessing the fire behavior of woods modified by N-methylol crosslinking,thermal treatment,and acetylation

Wood products are often treated by different techniques to improve their longevity when used as building materials. Most of the time, the goal is to increase their resistance to weathering effects, deformations in material dimensions or biotic decomposition. These wood treatment techniques have a significant impact on pyrolysis and burning behavior. The general effects of three different common wood treatments on flame retardancy were investigated by comparing treated woods with their untreated counterparts and with other kinds of wood. While the acetylation of beech leads to a slightly increased fire hazard, the thermal treatment of wood and crosslinking of cellulose microfibrils dimethyloldihydroxy-ethyleneurea show a limited flame retarding effect. Switching to woods with a higher lignin content, and thus higher char yield, however, results in a more pronounced improvement in flame retardancy performance. This article delivers a comprehensive and balanced assessment of the general impact of different wood modifications on the fire behavior. Further, it is a valuable benchmark for assessing the flame retardancy effect of other wood modifications.     

Physico-mechanical studies of wood fiber reinforced composites

Wood polypropylene composites (WPC) of different compositions (30, 40, and 50%) have been prepared using maleic anhydride–polypropylene copolymer of different percentage (5 and 10% relative to their wood fiber content). Tensile, flexural, fracture toughness, and impact test of the prepared WPC were carried out. From the results, it is observed that the hard wood fiber–polypropylene composites, by using maleated polypropylene (MAH-PP), show comparatively better performance to soft wood fiber–polypropylene composites. Tensile strength and charpy impact strength have been increased to a maximum of 50 and 20%, respectively. The damping index has been decreased by 60% when 10% of MAH-PP has been used. Water absorption and scanning electron microscopy of the composites are also investigated.     

Improvement of the flame retardancy of plasticized poly(lactic acid) by means of phosphorus‐based flame retardant fillers

The aim of this study is to improve the flame resistance and toughness of poly(lactic acid) (PLA) with the addition of low amount of flame retardant fillers and plasticizer simultaneously. Poly(ethylene glycol) (PEG) was used as plasticizer for PLA. Ammonium polyphosphate, boron phosphate, and tri‐phenyl phosphate (TPP) were used as flame retardant additives. Among these flame retardant additives, boron phosphate was synthesized from its raw materials by using microwave heating technique. Characterization of PLA/PEG‐based flame retardant composites was performed by conducting tensile, impact, differential scanning calorimeter, thermal gravimetric analysis, scanning electron microscope, limiting oxygen index, and UL‐94 vertical burning tests. Mechanical tests showed that the highest tensile strength, impact strength, and elongation at break values were obtained with the addition of ammonium polyphosphate and TPP into PLA/PEG matrix, respectively. Scanning electron microscopy analysis of the composites exhibited that the more homogeneous filler distribution in the matrix was observed for TPP containing composite. The best flame retardancy performance was also provided by TPP when compared with the other flame retardant additives in the plasticized PLA‐based composites.     

Bonding performance of melamine-urea-formaldehyde and phenol-resorcinol-formaldehyde adhesives in interior grade glulam

Wood moisture content (MC) affects the glued laminated beam (glulam) bonding strength. Selected adhesives were Phenol-Resorcinol-Formaldehyde (PRF) and Melamine-Urea-Formaldehyde (MUF) adhesives with 1, 1.5 and 2% (w/w) carboxymethyl cellulose (CMC) formic acid solutions. Douglas fir (pseudotsuga menziesii) from North America was used in the test. The bonding behavior of these adhesives with wood at 12 and 18% MC were investigated. The study focused on the effect of 18% MC on shear strength performance of MUF and PRF adhesives and optimizing the formula of CMC formic acid solution. Compressive shear strength of wood with MUF adhesive with 2% (w/w) formic acid solution at 12 and 18% MC stabilized at 10.6 and 10.0 MPa, respectively, which were 17 and 16% higher than that with PRF adhesive at the same condition. At 12–18% MC, MC had a little effect on bonding strength. However, 18% MC wood with PRF adhesive had 52.2% less initial strength increasing rate than that of 12% MC wood. 18% MC wood with MUF adhesives with 1, 1.5 and 2% (w/w) CMC formic acid solutions had 16.0, 15.5 and 27.0% less initial strength increasing rates than that of 12% MC wood, respectively. MUF adhesive using 2% CMC formic solution required the shortest press time at 12 and 18% MC about 1.6 and 2.7 h, respectively. The strength of PRF adhesive was significantly affected by wood MC and enough press time is essential for the proper bonding strength.     

Comparison of disodium octaborate tetrahydrate‐based and tannin‐boron‐based formulations as fire retardant for wood structures

Boron‐based formulations are used to improve the service life of timber. On the one hand, boron‐treated wood increases resistance to biological attacks (e.g. by fungi and insects), and on the other hand, it renders wood more resistant to burning. In the present study, we analyse the fire behaviour of some water‐borne formulations containing boron. A completely inorganic formulation (disodium octaborate tetrahydrate (DOT)) is compared with new‐generation tannin‐based wood preservatives in which the flavonoid network is used to fix the boron to wood. The study of the fire behaviour was carried out according to four specific fire tests: (i) dripping; (ii) short‐term exposure; (iii) long‐term exposure and (iv) the limiting oxygen index. The Scots pine (Pinus sylvestris L.) specimens treated with DOT have shown a complete efficacy against fire after all tests were completed. It should also be noted that very positive results have also been achieved by the tannin‐based solutions. DOT has to be preferred when high performance is required, but exclusively for interior applications. The use of tannin‐based formulations can be suitable for outdoor fire protection and also for indoor applications when specific aesthetic requirements should be fulfilled. Copyright © 2013 John Wiley & Sons, Ltd.     

木粉粒径对木塑复合材料性能的影响

采用不同粒径的木粉填充高密度聚乙烯制备木塑复合材料，研究了木粉粒径对木塑复合材料力学性能和加工流动性的影响。结果表明：木粉粒径对复合材料性能的影响十分明显，较大粒径的木粉有利于复合材料弯曲性能和冲击强度的提高。木粉粒径从100μm增加到850μm，复合材料弯曲强度增加10．4％，弯曲模量增加56．3％，冲击强度增加14．6％。随木粉粒径的增大，拉伸强度呈现先上升后下降的趋势，在200μm时出现最大值。木粉粒径对熔体流动速率（MFR）和密度的影响十分明显，大粒径的木粉使复合材料具有较高的MFR和较低的密度。     

B/Fe_2O_3/NC复合物的制备及其对HTPB/AP推进剂性能的影响

为改善硼粉(B)的性能和纳米氧化铁(Fe_2O_3)在固体推进剂中的分散性,用静电喷雾法制备了B/Fe_2O_3/NC复合物,采用扫描电镜(SEM)表征了复合物的表面形貌,用TG-DSC分析了复合物的热性能及其对HTPB/AP推进剂热性能的影响,并用燃速测试和密闭爆发器实验研究了该复合物对HTPB/AP推进剂燃烧性能的影响。结果表明,所制备的B/Fe_2O_3/NC复合物均以团聚体的形式存在,复合物中B的活性提高,其氧化反应温度提前;团聚硼粉对HTPB/AP推进剂燃烧性能的改善效果明显优于原料硼粉;加入Fe_2O_3后,会进一步改善含硼推进剂的燃烧性能,而且随Fe_2O_3含量的增加,在密闭爆发器中HTPB/AP推进剂达到最高压力所需的时间逐渐减小。当Fe_2O_3的质量分数为8%时,推进剂在常压空气中的燃速最大,为不添加B/Fe_2O_3/NC复合物的HTPB/AP推进剂的2.77倍。B/Fe_2O_3/NC复合物对推进剂的热分解具有一定催化作用,且随Fe_2O_3含量的增加催化作用增强。     

建筑模板用聚乙烯基木塑复合材料的制备及其性能

以聚乙烯为基体,分别与木片、木质纤维、木质纤维粉制备了聚乙烯基木塑复合材料。分别利用液体石蜡、甲基丙烯酸甲酯、NaOH乙醇溶液、邻苯二甲酸酐乙醇溶液、H2O2乙醇溶液对木片、木质纤维、木质纤维粉进行预处理,并考察了相应木塑复合材料的拉伸强度和胶合强度。结果表明:邻苯二甲酸酐乙醇溶液和H2O2乙醇溶液对木材表面改性处理效果较为明显,相应的木塑复合材料的拉伸强度和胶合强度也更高;与木质纤维粉和木片相比,木质纤维与聚乙烯具有更好的相容性;当木质纤维质量分数为30%时,采用H2O2乙醇溶液预处理后,木塑复合材料的拉伸强度为28.2 MPa,胶合强度为8.68 MPa;利用邻苯二甲酸酐乙醇溶液预处理后,木塑复合材料的拉伸强度为26.7 MPa,胶合强度为7.92 MPa。     

PVC／木粉复合材料抗冲改性研究

用甲基丙烯酸、丙烯酸丁酯、甲基丙烯酸甲酯三元共聚物P（MAA—BA—MMA）对木粉进行预处理,再利用CPE、ACR和nano—CaCO3对PVC／木粉复合材料进行增韧改性。结果表明,木粉经P（MAA—BA—MMA）预处理后,使用ACR增韧时效果最好,其拉伸强度、弯曲强度、冲击强度和断裂伸长率分别提高了7．97％、5．26％、68．85％和571．26％。SEM结果表明,木粉预处理后再增韧,复合材料界面模糊,断面呈一定的韧性断裂特征。     

The role of particle size of particulate nano-zinc oxide wood preservatives on termite mortality and leach resistance

Historically most residential wood preservatives were aqueous soluble metal formulations, but recently metals ground to submicron size and dispersed in water to give particulate formulations have gained importance. In this study, the specific role nano-zinc oxide (ZnO) particle size and leach resistance plays in termite mortality resulting from exposure to particulate ZnO-treated wood was investigated. Southern yellow pine (SYP) sapwood impregnated with three concentrations of two particle sizes (30 and 70 nm) of ZnO were compared to wood treated with soluble zinc sulphate (ZnSO₄) preservative for leach resistance and termite resistance. Less than four percent leached from the particulate nano-ZnO-treated specimens, while 13 to 25% of the zinc sulphate leached from the soluble treated wood. Nano-ZnO was essentially non-leachable from wood treated with 5% formulation for the 30-nm particle size. In a no-choice laboratory test, eastern subterranean termites (Reticulitermes flavipes) consumed less than 10% of the leached nano-ZnO-treated wood with 93 to 100% mortality in all treatment concentrations. In contrast, termites consumed 10 to 12% of the leached ZnSO₄-treated wood, but with lower mortality: 29% in the 1% treatment group and less than 10% (5 and 8%, respectively) in the group of wood blocks treated with 2.5 and 5.0% ZnSO₄. We conclude that termites were repelled from consuming wood treated with nano-ZnO, but when consumed it was more toxic to eastern subterranean termites than wood treated with the soluble metal oxide formulation. There were no differences in leaching or termite mortality between the two particle sizes of nano-ZnO.