人工林杉木胶合工艺优化研究

采用SAS全因子试验设计,研究了胶粘剂类型、涂胶量、单位压力、加压时间和胶合面纹理五个因子对人工林杉木木材胶合性能的影响,并对其胶合工艺进行了优化。研究结果表明:胶粘剂类型对杉木木材常态胶合剪切强度和木破率的影响不显著,但是老化处理后API和PF的胶合剪切强度和木破率比PVAc和UF的要高;在以API为胶粘剂时,涂胶量、单位压力、加压时间和胶合面纹理对杉木胶合剪切强度和木破率的影响显著,优化的胶合工艺为涂胶量250g/cm2,单位压力1.5 MPa,加压时间50 min和胶合面纹理为弦切面-弦切面。     

人工林桉树木材指接工艺研究

以窿缘桉、柠檬桉、尾巨桉、巨桉四种人工林桉树木材为研究对象,研究嵌合度、端压,指形和胶粘剂四个工艺因子对指接材强度性能的影响.试验结果表明:四个工艺因子对指接材的抗弯强度有显著影响,对抗弯弹性模量影响不显著;四种桉树在嵌合度为0.1 mm,端压分别为9.5MPa、9.5MPa、9.5MPa和11MPa时可以获得较高的指接强度性能.在本试验条件下,V型与H型指接材的强度性能基本一致,但H型的抗弯强度略高于V型指接材;从破坏类型上看,PVAc指接材的破坏多属于胶层破坏,API指接材多属于复合破坏.     

脲醛树脂浸渍改性杨木胶合及涂饰性能

研究脲醛树脂浸渍改性杨木的胶合和涂饰性能。结果表明:本试验范围内,胶黏剂种类对木材胶合性能有重要的影响,三种胶黏剂对改性材的胶合剪切强度均大于素材,并且改性材木破率低于素材;脲醛树脂胶合改性材的剪切强度、木破率均较高。涂料种类对浸渍改性杨木涂饰性能有影响,硝基漆和水性漆涂饰的改性材和素材的漆膜附着力均为优等品,而聚氨酯漆漆膜附着力不合格,改性前后杨木的漆膜附着力基本没有改变。     

热处理对巨尾桉/聚乙烯膜复合材料性能影响

以桉木为基材,通过聚乙烯膜进行胶粘,采用热压-冷压工艺制备巨尾桉/聚乙烯膜复合材料。并通过对巨尾桉单板进行高温热处理,研究了不同热处理温度和时间对巨尾桉/聚乙烯膜复合材料物理力学性能(胶合强度、静曲强度和弹性模量)的影响。结果表明:热处理温度和时间对复合材料的性能影响显著;当热处理温度140℃,处理时间0.5h或1h;处理温度160℃,处理时间0.5h时,热处理后复合材料胶合强度高于未处理胶合强度。本实验为热塑性树脂复合材料界面结合的研究提供一定的理论依据。     

柞木弦／径切面胶合强度的试验研究

对柞木木材自身弦／径面强度及其水性高分子异氰酸酯(API)胶粘剂胶合试件弦／径面胶接强度进行了研究。结果表明:柞木木材API胶粘剂弦／径面胶合试件常态压缩剪切强度存在着差异;柞木径切面API胶合试件的常态压缩剪切强度比弦切面胶合试件的常态压缩剪切强度高;径切面API胶合试件的常态压缩剪切强度是弦切面的1.22倍;而柞木弦、径面API胶合试件的反复煮沸压缩剪切强度没有显著性的差别。柞木木材本身弦／径面顺纹抗剪强度试验结果表明:柞木木材径向的顺纹抗剪强度为14.41MPa,柞木木材弦向的顺纹抗剪强度为14.97MPa,尽管弦径向间差别不大,但经t-检验证明:柞木的弦／径向间顺纹抗剪强度有显著性的差别,柞木的径向顺纹抗剪强度比弦向顺纹抗剪强度小。     

广西的桉树及制浆造纸

广西柳江造纸厂 1982年承担国家科技攻关项目《柳桉、柠檬桉造纸速生丰产培育技术及其应用研究》课题。并于 1990年进行全桉木制浆造纸的中间生产试验。 1991年轻工业部组织专家进行论证和鉴定。攻关课题被评为“国内先进”。全按木制浆造纸为“国内首创”。 　　经过培育、试验和筛选，广西现有的桉木以柳桉、巨桉、柠檬桉、尾叶桉、巨尾桉较适宜于制浆造纸。窿缘桉心材颜色较深，不易蒸煮、难漂白。 　　上述桉树在广西一般每公顷平均年生长量在 12m3～ 15m3之间， 8年生至 10年生桉木即可砍伐制浆造纸。桉树 10年后生长缓慢。 　　柳桉、…     

碱处理对巨尾桉/聚乙烯膜塑复合材料性能的影响

采用碱预处理的方法处理巨尾桉,使用基材巨尾桉、胶合剂聚乙烯膜制备三层木塑复合材料,分析碱处理对复合材料力学强度的影响。结果表明:碱处理对复合材料的胶合强度、静曲强度和弹性模量都有显著的影响,对巨尾桉单板采用碱处理的方法可以有效提高复合材料的物理力学性能。     

尾巨桉材Ⅰ类胶合板制造技术的研究

采用正交试验法研究单板涂胶量、热压温度、热压时间3个因子对尾巨桉材Ⅰ类胶合板性能的影响,得出了较优的工艺参数.结果表明,单板涂胶量、热压温度、热压时间对尾巨桉胶合板的胶合强度影响显著,其中热压时间影响最大,热压温度其次,单板涂胶量最小;较优的生产工艺组合是单板涂胶量320g/m2、热压时间1.2min/mm、热压温度135℃.     

三种桂产桉叶油对常见致腐菌的抑制作用研究

采用水蒸气蒸馏法提取柠檬桉、窿缘桉、尾叶桉三种桂产桉叶挥发油,并用GC-MS对三种桉叶挥发油的化学成分进行分析;采用试管二倍稀释法测定了三种挥发油对食品中常见致腐菌（蜡状芽孢杆菌、姜瘟杆菌、痢疾杆菌、沙门氏菌、烟曲霉、黑曲霉）的最小抑菌浓度,并以亚硝酸盐为阳性对照。结果表明:三种桉叶挥发油的化学成分及含量有很大的差异,对供试菌种均有一定的抑制性,尤以柠檬桉叶挥发油的抑菌活性最为突出,有望应用于食品保鲜中。      

两种速生阔叶木原料P-RC APMP工艺制浆性能比较

介绍了以尾巨按和马占相思为原料,采用P-RC APMP工艺对比研究两者的化学机械法制浆性能。研究结果表明,由于材性的差异,两种木材原料的P-RC APMP工艺制浆性能差异较大。综合比较而言,相同的过氧化氢用量4．0％,氢氧化钠用量3．5％条件下,制得抗张强度相近的纸浆,马占相思比尾巨桉所需的磨浆电耗约低20％左右;纸浆得率比尾巨按约高3％左右;两者制得纸浆的白度相近均可达75％以上;物理强度性能远优于尾巨桉浆,相同的250ml加拿大游离度下．马占相思纸页的抗张强度可达到26．N·m／g以上;松厚度略低于尾巨桉浆。     

Adhesive bonding of beech wood modified with a phenol formaldehyde compound

Untreated (controls) and phenol–formaldehyde (PF)-modified beech wood (10 and 25?% solid content) were glued with phenol resorcinol formaldehyde (PRF) and polyvinyl acetate (PVAc). Shear strength of PRF-bonded specimens was higher than that of PVAc-bonded ones under dry and wet conditions irrespective of the pre-treatment. Under dry conditions, only PVAc-bonded specimens exhibited reduction in shear strength due to PF-modification with 25?% PF concentration as compared to the controls. PF treated wood provided inferior bonding under wet conditions with the exception of 25?% PF concentration specimens glued with PRF adhesive. Modification with PF resulted in a decrease of adhesive penetration into the porous network of interconnected cells, especially at 25?% PF concentration.     

杉木板条横向线拼工艺初探

探索通过浸胶线绳连接的方式横拼杉木板条取代传统胶拼。采用单线拉伸的方式测定浸胶线绳连接的胶接性能,研究浸胶线绳连接中线绳种类、胶种、开槽宽度等因素对浸胶线绳胶接破坏载荷的影响,分析优化浸胶线绳连接方式。结果表明,市售棉线及尼龙线作为连接线绳的破坏载荷较高,同时开槽宽度为1.5 mm时的破坏载荷优于开槽宽度为1.0 mm的破坏载荷;通过对浸胶线绳连接工艺参数的进一步优化,并结合工业化生产要求,可得最优的条件为:胶种为热熔胶,线绳为棉线,开槽深度为2.0 mm。利用该工艺制备的细木工板的横向静曲强度和表面胶合强度达到了国家标准GB/T 5849—2016《细木工板》的要求。     

Hydroxymethylated resorcinol (HMR) priming agent for improved bondability of wax-treated wood

The effects of hydroxymethylated resorcinol (HMR) on the tensile shear strength of wood joints treated with montan ester wax were studied with polyvinyl acetate (PVAc) and melamine formaldehyde (MF) adhesives. Untreated specimens which were bonded with MF and PVAc had similar bond strength properties under dry conditions, but MF bonded specimens’ tensile shear strength values were higher than that of PVAc glued specimens under wet conditions. With both adhesives tested, dry tensile shear strengths of wax-treated specimens were in a comparable range to those of untreated wood, while under wet conditions the strength values of wax-treated specimens were significantly lower than those of the controls. HMR priming increased the shear strength of PVAc bonded specimens under wet conditions and of MF-bonded specimens under dry and wet conditions. The effect on MF-bonded specimens, however, was much more pronounced under wet conditions.     

Curing behavior and bonding strength of two-component fast-setting adhesives prepared with phenol-liquefied <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> wood

Honeymoon adhesive is a special adhesive system that contains two components which are applied onto two substrates separately for glulam manufacturing to provide a fast-setting capability. It has been confirmed that phenol-liquefied wood can be used as a raw material for preparing phenolic resins. In this study, liquefied wood (LW) was obtained by liquefying Cryptomeria japonica wood in phenol with sulfuric acid as a catalyst. Resorcinol–formaldehyde resin (RF), phenol-resorcinol–formaldehyde resins (PRF), LW–PF and LW–PRF (synthesized using LW as a raw material), and RF/LW and RF/LW–PF (blended RF with LW and LW–PF) were prepared. The properties such as non-volatile content, pH, viscosity gelation time and DSC curing behavior of these resins were measured. The results show all resins can be cured at room temperature when paraformaldehyde is added as a hardener, except for the LW–PF. The honeymoon adhesive was prepared by using RF and PRF that contains 10% paraformaldehyde as the A-component and LW–PRF, RF/LW and RF/LW–PF without paraformaldehyde as the B-component. After mixing the A-component and B-component, the gelation time of RF and PRF can be shortened. The glued lumber was prepared by separately applying the A-component and B-component on the surface of two wood strips and combining them. The result shows using RF/LW–PF as the B-component has faster bonding strength development than others. When PRF and RF are used as the A-component, they have a bonding strength of over 5.4 MPa, the requirement of CNS 11031 standard for the glued lumber of C. japonica, at pressing times of 2 and 4 h, respectively.     

Thermal stability of glued wood joints measured by shear tests

The thermal stability of glued wood joints is an important criterion to determine the suitability of adhesives in the field of engineered wood. During their product life, glued wood joints can be exposed to high temperatures in various ways (direct exposure to the sun, fire, etc.). Thereby the cohesiveness of the adhesive must not degrade. This raises the question of how the strength of bonding changes under thermal load. The current investigation covers the influence of temperature (T=20 to 220°C) on the shear strength of glued wood joints. Different adhesive systems were investigated. With increasing temperature, the shear strength of solid wood and also of glued wood joints decreased. There were big differences in thermal stability and failure behaviour between the adhesive systems as well as within the polyurethane group. The thermal stability of one-component polyurethane systems can be greatly varied by modifying their chemical structure. Well adapted one-component polyurethane adhesives reach a strength similar to that of phenol resorcinol resin.     

Utilization of bark flours as additive in plywood manufacturing

Increasing demand for wood based panel products and shortage of wood as raw material have triggered many efforts to utilize residues generated annually by the forest industries including a large portion of bark in panel production. In this study, the effects of using bark flours as additives obtained from different wood species (walnut, chestnut, fir and spruce), having much polyphenol content, on some physical and mechanical properties and formaldehyde emission of plywood panels were examined. Wheat flour, which has been used widely as additive in plywood manufacturing, served as control. Plane tree (Platanus orientalis) logs were obtained for veneer manufacturing. Urea formaldehyde (UF) resin with 55 % solids content was used as adhesive. The bonding shear strength, bending strength, modulus of elasticity (MOE), density, equilibrium moisture content and formaldehyde emission of plywood panels were determined according to related standards. It was found that the use of flours obtained from the barks of chestnut and fir trees in the glue mixture decreased the formaldehyde emission of panels. The bonding strength values of the test panels made using the glue mixture including the flour of walnut and spruce barks as additive were lower than those of the panels with adhesive containing the flour of fir and chestnut barks. The panels manufactured with adhesives including the flour of fir bark gave the highest bending strength and modulus of elasticity values.     

烷基烯酮二聚体用于杉木疏水改性的研究

利用两种烷基烯酮二聚体（AKD）SF30和H10分别浸渍处理杉木木材样品,研究AKD用量对杉木疏水性能的影响。结果表明,使用H10疏水剂处理的木材,当疏水剂浓度为0．4％时,杉木样品表面水接触角达到最大值127．06°,使木材具有一定的疏水性,当增加疏水剂的用量,水接触角又呈现下降的趋势。当使用SF30疏水剂时,试件的水接触角也明显高于未处理的木材试件,其最大值出现在SF30浓度为0．3％时。     

脲醛树脂废胶液制造胶合板工艺及性能研究

研究将脲醛树脂废胶液与水混合、中和处理、异味处理、磨浆、过滤得到混合浆液,将混合浆液按一定比例添加至酚醛树脂中,用于Ⅰ类胶合板及竹木复合集装箱底板用胶合板生产.研究结果显示,混合浆液添加比例8％和15％条件下,7层胶合板和21层竹木复合集装箱底板用胶合板胶合强度、浸渍剥离性能均满足Ⅰ类胶合板指标要求;混合浆液添加比例为...