氨基腰果酚的合成、表征与特性的研究

采用一步环氧化法对腰果酚侧链进行氧化，其环氧化物与多元胺反应生成氨基腰果酚。讨论了氨基腰果酚的合成条件，并通过元素分析、红外光谱等探讨氨基腰果酚的生成过程、结构特征和性能。结果表明，腰果酚侧链上烯烃基环氧化生成环氧基，然后环氧基与多元胺发生加成反应。该加成物结构中存在-OH、-NH-等功能基，具有能与环氧树脂进行固化交联以及吸附重金属离子的性能。     

微米木丝粉孔穴对PM2.5的过滤性能的实验

通过实验研究来验证微米木丝粉孔穴对PM2.5吸收能力的影响,从而研究微米木丝粉的过滤性能。实验分析可知,利用微米木丝粉制得的滤芯,其表面孔穴越多,其对汽车尾气中的PM2.5等颗粒的吸附效果更好。     

丙烯腈/木粉接枝共聚物的合成及其水解物的吸附特性研究

以Fe^2 /H2O2作为引发剂，将丙烯腈和木粉进行接枝共聚，得到丙烯腈／木粉接枝共聚物（PANW），再经适度水解的方法合成阳离子交换树脂－羧基木粉。研究影响接枝共聚反应的各中因素和水解条件，并讨论羧基木粉对重金属和阳离子型染料的吸附特性。实验结果表明：（1）在适量引发剂（FeSO4.7H2O-1g)和适当温度（60℃）作用下，可得到较高接枝增量和接枝率的PANW；（2）在PANW的水解反应中，在碱性催化剂作用下，可得到羧基含量高的产物，但收率较低；而在酸性催化剂作用下，则得到羧基含量低的产物。但收率较高；（3）羧基木粉对阳离子型染料－碱性桃红的吸附容量与起始浓度有关，本实验中，羟基木粉对碱性桃红的吸附容量最高可达500mg/g，对Cu^2 的吸附容量最高可达39mg/g；（4）经0．3mol/L HCl再生4次后，羧基木粉对碱性桃红的吸附因子容量保持在440mg/g以上，在含有多种金属主子的溶液中，羧基木粉优先吸附Fe^3 等硬酸型离子。     

多胺型螯合棉纤维的制备与吸附性能研究

棉纤维经碱化,环氧化,烯胺化,制得了三种多胺型系列离子螯合棉纤维,讨论了影响环氧化,烯胺化的各种因子,给出了一种简便的环氧值的测定方法,同时也讨论了该类螯合剂的吸附与解吸性能。     

不同助剂对木粉腻子性能的影响

以固体含量为16％的聚醋酸乙烯酯乳液和500目木粉为主要原料,加入两种助剂刺备木粉腻子,讨论助剂种类及加量对木粉腻性能的影响。结果表明：两种助剂均可有效改善木粉腻子的性能,并随其加量增大,腻子的耐水性、耐磨性明显提高;当助剂环氧树脂加量为8．0％、异氰酸酯加量为2．0％时,配制的两种腻子综合效果最佳。     

端氨基超支化聚合物接枝双醛基纳米纤维素的 制备及其对Ni2+的吸附

通过聚合反应制得一种端氨基超支化聚合物(HBP-NH_2),并以桉木浆为原料,经超声波辅助-TEMPO氧化制得羧基化纳米纤维素(CNC)、再经高碘酸钠氧化制得双醛基纳米纤维素(DNC),最后利用HBP-NH_2对DNC进行氨基化改性,得到端氨基超支化聚合物接枝双醛基纳米纤维素(HBPN-DNC),并对反应条件进行优化,当10%的HBP-NH_2溶液加入量为10 mL,反应温度为70℃,反应时间为4 h时N元素质量分数最高,达到6.0%。采用多种方法对纳米纤维素的结构和性能进行了表征,结果表明:氨基成功地接枝到了纳米纤维素链上,使得分子链变长,HBPN-DNC的热稳定性提高。HBPN-DNC对Ni(II)的吸附性能研究表明:室温条件下,当HBPN-DNC吸附剂用量为0.1 g,溶液初始质量浓度为500 mg/L且pH值为5.0的条件下吸附3 h,吸附量为150.21 mg/g。吸附过程符合准二级动力学吸附模型和Langmuir等温吸附模型,说明其吸附过程主要为单分子层的化学吸附。     

前处理方法对杨木木粉改性反应以及改性木粉热流动性的影响

研究了几种前处理方法对杨木木粉的改性反应和改性杨木木粉热流动性、溶解性的影响。发现加热预处理和饱和氯水前处理都会使木素的三维结构产生变化，从而使羟乙基化木粉产生热流动性，同时也降低了苄基化木粉的粘流温度（Ｔｆ０。几种前处理方法也使改性木粉在某些溶剂中的溶解度有不同程度的提高。     

新型胶合板水性木质复合覆面填补材料的制备和评价北大核心

探究了基于木纤维粒径/木粉种类差异填充胶合板缝隙的复合腻子配方、影响因素、性能评价,致力于胶合板素板表面缝隙填充、平整度调控的技术开发。采用单因素条件探讨了温度、木粉种类、木纤维目数等对腻子性能的影响。结果表明:添加木纤维的腻子填充材料除表干时间略高于未添加木纤维的对照组外,耐磨性、干强度、湿强度、相容性、稳定性相比于未添加木纤维的腻子填充材料均有了明显提高。在木纤维目数一致的情况下,添加木纤维的种类不同也会对腻子的各项性能产生影响。其中湿强度与粗糙度优劣排列依次是:桉木粉、杨木粉、杂木粉、松木粉、竹粉;干强度优劣排列依次是:桉木粉、杂木粉、杨木粉、松木粉、竹粉;耐磨性优劣排列依次是:杨木粉、松木粉、杂木粉、桉木粉、竹粉。木纤维的种类对腻子的表干时间、相容性、稳定性没有显著影响。     

苄基化木粉与塑料界面相容性研究

采用氯化苄对木粉进行改性,探讨了苄基化木粉的表面自由能、极性和热塑性,并测试了苄基化木塑复合材料的拉伸强度和静曲强度。结果表明,苄基化木粉自由能低、极性小,与塑料的相容性好、热塑性好,苄基化木塑复合材料的强度高。     

壳聚糖处理对木材染色的助染效果及其机理的研究

采用酸性染料酸性橙Ⅱ对经壳聚糖处理的毛白杨原木木粉、苯醇抽提木粉以及木材主要组分进行染色，并用等物质的量的强碱、弱碱、强酸、弱酸以及水和有机溶剂处理相同质量经壳聚糖处理的原木木粉与壳聚糖染色试样，测定其助染效果和确定其助染机理。结果表明：壳聚糖处理能显著提高酸性染。料对毛白杨原木木粉、苯醇抽提木粉、纤维素、半纤维素和木质素的上染率，其助染机理是与木材组分结合的壳聚糖分子的氨基与酸性染料上的磺酸基以离子键结合，形成磺酸盐，从而提高了上染率。     

杨树浸渍改性处理材尺寸稳定性研究

利用聚乙烯醇缩甲醛改性剂对杨树木材进行浸渍改性,对其改性材的尺寸稳定性进行研究。结果表明:改性材的径向、弦向和体积干缩率与素材相比均有不同程度的下降;从全干到吸水饱和状态的过程中,当改性剂达到一定浓度时,改性材的径向、体积湿胀率与素材相比有明显下降,弦向线湿胀率下降不明显。从气干到吸水饱和状态的过程中,改性材的径向、弦向湿胀率与素材相比均有不同程度的下降;改性材体积湿胀率随着改性剂浓度的上升而呈下降趋势,当改性剂浓度为30%时,改性材体积湿胀率为6.85%,与素材相比下降了5.54%。改性材吸水率随改性剂浓度的上升而下降,最低可达159%;改性材的抗干缩系数(ASE)随改性剂浓度上升而增加,最大可达47.8%。改性材的尺寸稳定性能要明显优于杨树素材。     

改性木材命名规则探讨

澄清了改性木材的概念,指出其形态限于木材整体和单板;分析了胶压木的特性及名称,认为它不应归于改性木材;通过辨析现有改性木材的类别及名称,发现其存在“命名方法笼统、同物异名或同名异物、归类混乱”等问题;通过分析出现这些问题的原因,对改性木材命名规则进行了初步探讨,以便推动标准化工作和新材料的命名与推广。     

杨木材性对酚醛树脂浸渍改性材的影响

采用低分子量酚醛树脂对速生杨木进行浸渍处理、干燥定型,使树脂固化制得改性材。试验表明：低分子量酚醛树脂对杨木具有较好的浸注性,改性材的密度和力学强度均有明显的提高,两组试件改性后浸注性和密度相差不大,但前期经过热水处理的试件改性后密度相对均匀,力学强度略好于直接浸渍的试件。杨木自身材性对改性后物理力学性能的影响各不相同,在实际生产中要根据指标的重要性程度选取最佳方案。     

Shear strength of furfurylated,N-methylol melamine and thermally modified wood bonded with three conventional adhesives

The shear strength of furfurylated, N-methylol melamine (NMM) and thermally modified wood bonded with emulsion polymer isocyanate, polyvinyl acetate (PVAc), and polyurethane (PU) adhesives was examined. Furfurylation and NMM modification of Scots pine had a significant negative effect on the bonding strength with all adhesives irrespective of the treatment intensity. The obtained low-shear strength values were related to the brittle nature of the wood after modifications rather to the failure of the bondline. PVAc showed a better bonding performance with both furfurylated and NMM modified wood while the combination of furfurylated wood and PU gave the highest reduction in bonding strength (47–51%). Shear strength also decreased significantly after thermal modification in both Scots pine (36–56%) and beech (34–48%) with all adhesives. With the exception of thermally modified beech samples bonded with PU, bondline was found to be the weakest link in thermally modified wood as it was revealed by the wood failure surfaces. Bondline thickness and effective penetration of adhesives did not relate to the shear strength of all modified wood materials. The lower shear strength of modified wood could be attributed to other factors, such as the reduced chemical bonding or mechanical interlocking of adhesives, and the reduced strength of brittle modified wood substrate.     

Hydrophobization of wood surfaces: covalent grafting of silicone polymers

 The hydrophilicity of Maritime pine wood surfaces was modified by silicone, an extremely hydrophobic material. A generic method for the introduction of a variety of silicones at the surface of pre-treated wood was developed. The initial treatment of wood with maleic anhydride and allyl glycidyl ether resulted in oligoesterified wood bearing terminal alkenes. The hydro- osilylation of these groups, performed with hydride-terminated silicones, led to very hydrophobic surfaces, even after extensive soxhlet extraction with good solvents for silicones. Thze presence of silicon, only at the surface of hydrosilylated wood, was confirmed by ESCA. The silicones appear to be attached to the wood by covalent bonds. Received 20 December 1998     

Gluability of thermally modified beech (Fagus silvatica L.) and birch (Betula pubescens Ehrh.) wood

Abstract

One of the main disadvantages of wood is hygroscopicity resulting from its polar character. The sorption–desorption of water causes unwanted swelling and shrinkage in wood. Thermal modification substantially reduces this inconvenient feature. Unfortunately, the same chemical changes that reduce water sorption alter the polar character of the material and result in poorer wetting of thermally treated wood by waterborne adhesives. Gluability of thermally modified beech (Fagus silvatica L.) and birch (Betula pubescens Ehrh.) wood with two commercial amino resins, melamine–urea–formaldehyde (MUF) and melamine–formaldehyde (MF), and a two-component polyurethane (PUR) adhesive was investigated. Both wood species were modified according to two temperature regimes: 160°C and 190°C. Shear strengths of the joints were then determined according to EN 205:2003 standard. The results showed that thermally modified beech and birch wood can be effectively glued not only with commercially available PUR adhesives, but also with aqueous MF and MUF resins. The resultant shear strengths of the joints were limited by the strength of the thermally modified substrate.     

Preparation of cyclodextrin grafting wood flour and investigation of the release characteristics of eugenol

Poplar wood flour, a low-cost and abundantly available material, was modified by grafting β-cyclodextrin (β-CD) in the presence of citric acid or 1,2,3,4-Butanetetracarboxylic acid, aiming to expand the application of wood flour. The products were characterized by Fourier transform infrared spectroscopy and the technique of phenolphthalein probe. The grafting conditions of β-CD onto wood flour including curing temperature, β-CD concentration in impregnation solution and catalyst were also evaluated by the technique of phenolphthalein probe. Besides, eugenol (EG), an antibacterial fragrant guest molecule, was loaded on the modified wood flour by lyophilization, and its release characteristics were investigated by Thermo-gravimetric. The results revealed that the modified wood flour material had a thermo-protective effect on the volatilization of EG and the encapsulated EG content was reached to 1.31 %, which could demonstrate a potential application in the finishing and packing areas.     

材性改良研究：Ⅰ.X射线木材密度测定

利用Ｘ射线衍射（Ｄ－ｍａｘ３Ｂ型）改装成直接扫描式Ｘ射线木材密度计，可快速、高效测定木材密度组成，即木材平均密度，平均早材密度，平均晚材密度，最大木材密度，最小木材密度，木材密度梯度和木材密度的变异幅度，为材性改良提供了新手段，本文用Ｘ射线木材密度计测定１７个树种木材密度。     

生物矿化原理与木材纳米结构复合材料

为促进传统木材改性技术产生新的发展 ,将生物矿化概念导入到木材科学与技术的研究领域中。本文综述了生物体系中生物矿化作用的基本内涵 ,探讨了基于这些原理之上的木质基纳米材料控制合成的构想 ,即通过立木形成层细胞分生的有机分子和无机离子在界面处的相互作用来设置矿化位 ,调节微环境 ,建立饱和溶液、提供有机质、搬运离子、加入添加剂等来控制生物矿化作用的方向和过程 ,实现用活立木制备木材纳米结构复合材。     

Durability of thermally modified Norway spruce and Scots pine in above-ground conditions

Abstract

One of the main objectives of thermal modification is to increase the biological durability of wood. In this study the fungal resistance of Norway spruce and Scots pine, thermally modified at 195°C and 210°C, was studied with a lap-joint field test. Untreated pine and spruce and pine impregnated with tributyl tin oxide (TBTO) and copper, chromium and arsenic (CCA) were selected as reference materials. The evaluations were carried out after 1, 2 and 9 years of exposure. After 1 and 2 years of exposure mainly discoloration was detected. Only the untreated pine was slightly affected by decay fungi. There were significant differences in the decay ratings of untreated and thermally modified wood materials after 9 years in the field. While the untreated wood materials were severely attacked by decay fungi or reached failure rating, only small areas of incipient decay were detected in the thermally modified samples. Thermally modified pine was slightly more decayed than thermally modified spruce. The only wood material without any signs of decay was CCA-treated pine, since some of the TBTO-treated pine samples were also moderately attacked by fungal decay. The results of the lap-joint test had a good correlation with mass losses in a laboratory test with brown-rot fungi.