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Curing Process of Phenol Formaldehyde Resin for Plywood under Vacuum Conditions

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Journal of Renewable Materials 2023年第9期11卷 3447-3461页

作者： Guobing Xiong Lu Hong zehui ju Xiaoning Lu juwan Jin College of Furnishings and Industrial Design Nanjing Forestry UniversityNanjing210037China School of Forestry&Landscape Architecture Anhui Agricultural UniversityHefei230036China College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China

The study characterized the curing behaviors of phenol formaldehyde(PF)resin under different vacuum degrees and explored the properties of 9-ply plywood panels hot-pressed under both vacuum and atmospheric *** changes in core temperature and moisture content of the plywood mats during hot pressing were investigated as *** was found that the gel times and gel temperatures of PF resin decreased with the increase of vacuum degree using a self-made *** spectra indicated the degree of polycondensation of hydroxymethyl gradu-ally increased with the increase in *** was also observed that a higher degree of vacuum led to a slower polycondensation reaction rate of PF *** different hot-pressing processes,the bonding strengths in the innermost and uppermost gluelines of the vacuum hot-pressed plywood panels were up to 30%–50%higher than their counterparts of conventional hot-pressed products.A less difference in the bonding strengths between these two gluelines was also observed for vacuum hot-pressed *** addition,the core of vacuum hot-pressed plywood was found to have a greater heating rate and higher temperature at thefinal stage of hot pressing,which was beneficial to cure the PF *** results from this study indicate a promising potential of introducing a vacuum during hot pressing to improve the quality and productivity of plywood products and provide a basis for adopting vacuum to hot press wood composites.

关键词： Phenol formaldehyde resin vacuum gel time FTIR plywood bonding strength

Improving the Properties of Fast-Growing Chinese Fir by Vacuum Hot Pressing Treatment

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Journal of Renewable Materials 2021年第1期9卷 49-59页

作者： Lu Hong Biqing Shu Qian He zehui ju Haiyang Zhang Xiaoning Lu College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Civil Engineering Yangzhou Polytechnic InstituteYangzhou225127China

Chinese fir was compressed by vacuum hot pressing and conventional hot pressing at different temperatures(180℃,200℃ and 220℃),*** color parameters of the heat-compressed sample were measured,the relative mechanical properties of the material were tested and changes in the chemistry of fir were investigated using Fourier transform infrared spectroscopy(FTIR)and Xray photoelectron spectroscopy(XPS).The results indicated that the color difference between compressed and untreated wood increased gradually with the increase of *** with the conventional hot pressing treatment,the color difference(ΔE*)of the Chinese fir treated by vacuum hot pressing decreased by 43.73%,69.91%,and 77.17%,*** mechanical properties(bending elastic modulus and bending strength)of Chinese fir treated by vacuum hot pressing were significantly *** 24-hour water absorption thickness expansion rate of fir treated by vacuum hot pressing is smaller than that of conventional hot *** is implied that vacuum hot pressing treatment is an effective method to produce compressed wood,which can improve the mechanical properties and dimensional stability of wood,and reduce the influence of carbonization on wood color.

关键词： Chinese fir vacuum hot pressing color mechanical properties dimensional stability

Study on the Bonding Performance of the Moso Bamboo Dowel Welded to a Poplar Substrate Joint by High-Speed Rotation

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Journal of Renewable Materials 2021年第7期9卷 1225-1237页

作者： Suxia Li Haiyang Zhang Biqing Shu Liangsong Cheng zehui ju Xiaoning Lu College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Furniture and Art Design Central South University of Forestry and TechnologyChangsha410004China College of Civil Engineering Yangzhou Polytechnic InstituteYangzhou225127China

The wood friction welding technique with its high bonding strength,low cost,high efficiency,and without any adhesive has been increasing concern in *** bamboo(Phyllostachys pubescens)and poplar(Populus sp.)are widely planted and used in the furniture industry,interior decoration,and wood structure construction in *** aim of this work was to investigate the bonding performance of moso bamboo dowel rotation welded joints with different dowel/receiving hole diameter *** results indicated that the ratio of dowel/receiving hole diameter was an important parameter that influenced the welding *** bonding strength of the bamboo-to-poplar welded joints at the optimal ratio of 10/7 was as high as 7.50 MPa,which was higher than that of the beech(Fagus sylvatica,L.),schima(Schima superba)dowels and PVAc glued *** temperature measurement results showed a peak temperature of bamboo dowel welding as high as 350–360°*** differences in the temperature curves between each dowel/hole diameter ratio group were observed at the three different hole depths,such as the friction time,peak temperatures,and stabilization time at the maximum temperature,which could explain the differences in welding strengths between different *** SEM results showed the temperature-induced softening,melting and flowing of cell-interconnected polymer material in the wood and bamboo struc*** addition,the bamboo fibers(mainly vascular bundles)were wrapped to form a dense continuous bonding layer,similar to the reinforced concrete,thus producing a good bonding *** Fourier transform-infrared spectroscopy(FT-IR)analyses showed that the high temperature resulted in the increase of the lignin relative content due to the degradation reaction of cellulose in the welding zone,which improved the bonding properties.

关键词： Moso bamboo rotation welding tensile strength optimal ratio poplar

Steam Exploded Peanut Shell Fiber as the Filler in the Rigid Polyurethane Foams

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Journal of Renewable Materials 2019年第11期7卷 1077-1091页

作者： zehui ju Qian He Tianyi Zhan Haiyang Zhang Lin Sun Lu Hong Xinyi Shi Xiaoning Lu College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Biology and the Environment Nanjing Forestry UniversityNanjing210037China.

In this study,steam exploded peanut shell fibers(SE-PSFs)were utilized to fabricate with rigid polyurethane foam(RPUF)in order to improve sound absorption performance and hydrothermal weather *** method of SE treatment,RPUF preparation and flame retardant treatment were selected to prepare SE-PSF/RPUF composites in this *** and mechanical properties including density,water absorption capacity,thickness swelling rate,compressive strength,thermal conductivity and average sound absorption coefficient of SE-PSF/RPUF were investigated and compared with the control(PRUF).The results showed that the density,water absorption capacity,thickness swelling rate and thermal conductivity showed an increasing trend with the increase of SE-PSFs *** strength of the composite material showed a downward trend with the increase of the SE-PSFs *** average sound absorption coefficient of the SE-PSFs/RPUF compared with PRUF significant increased,and the average sound absorption coefficient of the SE-PSFs/RPUF with SE-PSFs 40%was *** study getted the best ratio of flame retardants for 10%EG and 3%*** oxygen index was 35.56 vol%.

关键词： Steam explosion peanut shell fiber polyurethane composite flame retardant properties

Structure Design and Properties of Three-Layer Particleboard Based on High Voltage Electrostatic Field(HVEF)

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Journal of Renewable Materials 2021年第8期9卷 1433-1445页

作者： Man Yuan Lu Hong zehui ju Wenli Gu Biqing Shu Jianxin Cui Xiaoning Lu Zhiqiang Wang College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China

In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were *** to the test results,three-layer particleboard was *** face layers made with mixture of A,B,and *** core layer made with *** ratio of core layer to face layers is 50:***-layer particleboard were fabricated with 12%urea-formaldehyde(UF)resins and three different high voltage electrostatic field intensities(0 kv,30 kv,60 kv).The internal bond(IB)strength,modulus of rupture(MOR),modulus of elasticity(MOE),thickness swelling(TS),and water absorption(WA)of particleboard were *** density distribution of the three-layer particleboard were examined by vertical density profiles(VDP),and the bonding mechanism and functional groups changes in the particles were analyzed by FTIR *** results showed that HVEF treatment intensity play a remarkable role in properties of *** particleboard with higher electrostatic field intensities treatment has higher MOE,MOR,IB,and *** HVEF treatment(60 kv),the MOR,modulus of MOE,and IB of three-layer particleboard were 23.61 N/mm^(2),2787.09 N/mm^(2),and 0.86 N/mm^(2),*** indicated that the surface activity of wood particles was increased electric field treatment.

关键词： High voltage electric field three-layer particleboard physical property mechanical property

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提高杨木线性振动摩擦焊接胶合性能的研究

林业工程学报 2019年第3期4卷 32-37页

作者：孙启禹易庠华卢晓宁鞠泽辉张海洋南京林业大学材料科学与工程学院南京210037

研究了杨木线性振动摩擦焊接的干剪切强度、湿剪切强度和木破率。为提高杨木摩擦焊接的湿剪切强度与木破率,采用表面氧化、表面磺化以及表面涂覆的方式处理杨木板材,再经线性振动摩擦焊接进行黏合,使用万能力学试验机测得其剪切强度,对... 详细信息

研究了杨木线性振动摩擦焊接的干剪切强度、湿剪切强度和木破率。为提高杨木摩擦焊接的湿剪切强度与木破率,采用表面氧化、表面磺化以及表面涂覆的方式处理杨木板材,再经线性振动摩擦焊接进行黏合,使用万能力学试验机测得其剪切强度,对比表面处理前后剪切强度的变化,并利用傅里叶红外光谱分析了其表面处理前后基材和摩擦焊接层的化学基团变化情况,对胶合性能的变化做出解释。研究结果表明:杨木经过表面氧化磺化涂覆醋酸锌处理后,摩擦焊接层的干剪切强度为5.41 MPa,木破率为63%,与未处理的杨木相比,分别提高了48.22%和96.88%;湿剪切强度从0提高到1.34 MPa;摩擦焊接时厚度损失减少了46.4%。杨木分别经过表面氧化和表面磺化处理后,摩擦焊接层的干剪切强度仅为3.45和4.10 MPa,木破率为28%和42%,湿剪切强度为0.76和0.96 MPa。摩擦焊接层的红外光谱分析表明,经表面氧化磺化涂覆醋酸锌处理后,杨木中的纤维素和半纤维素分解,使木质素的相对含量有所增加,且活化了杨木中的—OH,与醋酸锌生成多醚,消耗了亲水性的—OH。

关键词：杨木摩擦焊接表面处理胶合性能胶合机理

两种国际通用乒乓球拍底板木材的固有频率及其影响因素

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林业工程学报 2016年第1期1卷 16-20页

作者：卢晓宁何倩姚有涛张海洋卢可鞠泽辉南京林业大学材料科学与工程学院南京210037 扬州怡人木业有限公司江苏扬州225008

以白梧桐、红桧两种国际通用乒乓板木材为试验材料，采用悬臂板一端固定的横向振动方法，研究木材试件的含水率、纹理角、树种、比模量与固有频率的关系。结果表明：木材试件固有频率随含水率的增加而降低，当含水率达到20％以上时，两... 详细信息

以白梧桐、红桧两种国际通用乒乓板木材为试验材料，采用悬臂板一端固定的横向振动方法，研究木材试件的含水率、纹理角、树种、比模量与固有频率的关系。结果表明：木材试件固有频率随含水率的增加而降低，当含水率达到20％以上时，两种树种固有频率值的变化趋于缓和。在含水率变化范围内，白梧桐试件固有频率值在66～56 Hz之间变化，红桧试件固有频率值在76～60 Hz之间变化。白梧桐、红桧两种树种试件的固有频率均值分别为56．32和69．01 Hz，但白梧桐试件固有频率的稳定性高于红桧，且径切板试件的固有频率大于弦切板的固有频率。在相同尺寸、测试方法和条件下，两种树种试件的固有频率值与比模量的关系符合薄板振动理论推导出的固有频率解的形式；红桧试件的比模量大于白梧桐试件的比模量。通过计算材料的弹性模量和密度，得出相应的比模量，从而可以判断出此材料的固有频率值。

关键词：乒乓球拍底板白梧桐红桧固有频率含水率纹理角比模量

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基于木材微观特性的胶合板隔声量模拟

林业工程学报 2018年第3期3卷 42-47页

作者：鞠泽辉林杨帆何倩洪璐张海洋詹天翼卢晓宁南京林业大学材料科学与工程学院南京210037 南京林业大学理学院南京210037

基于Biot理论的隔声模型,将马尾松等效为某一介质,通过木材微观特性(管胞长度、管胞直径、纹孔和孔隙率等),确定马尾松参数与等效介质密度和体积弹性模量之间的函数关系,对马尾松胶合板的隔声量进行预测。借助Matlab软件编制隔声量的相... 详细信息

基于Biot理论的隔声模型,将马尾松等效为某一介质,通过木材微观特性(管胞长度、管胞直径、纹孔和孔隙率等),确定马尾松参数与等效介质密度和体积弹性模量之间的函数关系,对马尾松胶合板的隔声量进行预测。借助Matlab软件编制隔声量的相应计算程序软件,同时,通过Matlab软件运用复合材料的弹性模量公式,预测马尾松胶合板的弹性模量。通过隔声量实测与模拟值比较可知,马尾松胶合板的隔声量实测值与理论值相吻合。对马尾松早晚材分开进行胶合板隔声量计算,并引入胶层的概念,从而提高隔声量预测的准确性。通过预测马尾松胶合板的弹性模量,进而计算出其相对应的临界频率,将模拟临界频率与实测临界频率进行对比分析。研究表明:酚醛树脂所制胶合板的隔声量高于脲醛树脂所制胶合板,同时,酚醛树脂对抑制吻合效应具有积极的作用;随着胶合板层数的增加,隔声量也相应有所提高,临界频率向高频移动,吻合谷变浅,有效抑制了吻合效应。本研究中的隔声量预测模型可为木质复合材料的隔声量预测提供有效参考。

关键词：传递函数隔声量预测木材微观特性胶层胶合板

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基于蒸爆法的无胶混杂型纤维板构成

扬州大学学报（自然科学版） 2020年第1期23卷 54-58,67页

作者：束必清任琴何倩鞠泽辉詹天翼张海洋石心怡卢晓宁南京林业大学材料科学与工程学院南京210037 扬州工业职业技术学院建筑工程学院江苏扬州225127

以中国资源丰富的速生杨木、竹材、核桃壳为原料,在爆破压力3.0 MPa、维压时间180 s下爆破杨木和毛竹,并在w(核桃壳粉)=10%,w(杨木纤维)=54%,w(竹纤维)=36%的材料配比下压制无胶混杂型纤维板.应用扫描电镜、化学成分分析和傅里叶变换红... 详细信息

以中国资源丰富的速生杨木、竹材、核桃壳为原料,在爆破压力3.0 MPa、维压时间180 s下爆破杨木和毛竹,并在w(核桃壳粉)=10%,w(杨木纤维)=54%,w(竹纤维)=36%的材料配比下压制无胶混杂型纤维板.应用扫描电镜、化学成分分析和傅里叶变换红外光谱等方法,对无胶纤维板的胶合构成成因进行研究.研究结果表明:蒸汽爆破能有效分离纤维,且长纤维保留较多;纤维细胞被压溃,纤维表面的碎片状物质有助于新木质素碳水化合物复合体的形成;纤维素、半纤维素的降解物在热压成板时可生成糠醛类化合物,并通过氢键使板材自胶合;将杨木、竹材混合爆破和加入核桃壳粉均对热压成板有利.

关键词：蒸汽爆破法无胶胶合混杂型纤维板环境扫描电镜傅里叶变换红外光谱