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Study on Physical and Mechanical Properties of Poplar Modified by phenol-formaldehyde Resin

Chinese Forestry Science and Technology 2008年第1期7卷 82-87页

作者： CHAI Yubo1 LIU Huanrong1 LIU Junliang1 LI Longzhe2 TANG Deguo3 1.Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R.China 2. Construction Bureau of Yanbian Korean Autonomous Prefecture, Yanji 133000, P.R.China 3. Forestry Bureau of Wangqing County, Wangqing 133200, P.R.China

Impregnation method can effectively improve physical and mechanical properties of wood. In this study, plantation poplar lumbers are impregnated by a low molecular weight phenol-formaldehyde resin solution with concentration of 30% under vacuum-pressure process, and then dried and machined according to the related standards. The results show that the physical and mechanical properties of poplar can be improved by the treatment, except for toughness. The average density of poplar increases from 0.397 to 0.710 g/cm3, the modulus of elasticity in static bending, the bending strength and the compressive strength parallel to grain of treated specimens increase by 56.71%, 112.97% and 87.69%, respectively, compared to the untreated. And the hardness values on radial and tangential sections, and nail holding power as well as abrasion resistance of treated specimens improve by 283.87%, 82.78%, 71.43% and 22.06%, respectively; while toughness decreases by 48.80%.

关键词： phenol-formaldehyde modification impregnation I-72 poplar (Populus xeuramericana) density strength plantion physical mechanical property

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Reinforcement of Lignin-Based phenol-formaldehyde Adhesive with Nano-Crystalline Cellulose (NCC): Curing Behavior and Bonding Property of Plywood

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Materials Sciences and Applications 2015年第6期6卷 567-575页

作者： Zhenbo Liu Yaolin Zhang Xiangming Wang Denis Rodrigue Key Laboratory of Bio-Based Material Science and Technology (Ministry of Education) & Northeast Forestry University Harbin China FPInnovations-Wood Products Quebec Canada Department of Chemical Engineering Laval University Quebec Canada

The curing behavior of lignin-based phenol-formaldehyde (LPF) resin with different contents of nano-crystalline cellulose (NCC) was studied by differential scanning calorimetry (DSC) at different heating rates (5, 10 and 20°C/min) and the bonding property was evaluated by the wet shear strength and wood failure of two-ply plywood panels after soaking in water (48 hours at room temperature and followed by 1-hour boiling). The test results indicated that the NCC content had little influence on the peak temperature, activation energy and the total heat of reaction of LPF resin at 5 and 10°C/min. But at 20°C/min, LPF0.00% (LPF resin without NCC) showed the highest total heat of reaction, while LPF0.25% (LPF resin containing 0.25% NCC content) and LPF0.50% (LPF resin containing 0.50% NCC content) gave the lowest value. The wet shear strength was affected by the NCC content to a certain extent. With regard to the results of one-way analysis of variance, the bonding quality could be improved by NCC and the optimum NCC content ranged from 0.25% to 0.50%. The wood failure was also affected by the NCC content, but the trend with respect to NCC content was not clear.

关键词： Lignin-Based phenol-formaldehyde Resin (LPF) Nano-Crystalline Cellulose (NCC) Curing Behavior Bonding Properties Plywood

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Kinetic Study of Curing phenol-formaldehyde/Tannin-formaldehyde Composite Resins

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Natural Resources 2015年第10期6卷 503-513页

作者： Hussein Ali Shnawa Ibraheem Kadum Ibraheem Ashwaq Aboud Shenta Polymer Research Center University of Basrah Basrah Iraq Department of Chemistry College of Education for Pure Science University of Basrah Basrah Iraq

This work presents a study on the uses of tannin-formadehyde derivative into phenolic resins. Eucalyptus tannins (T) were reacted with formaldehyde to form tannin-formaldehyde resin (TF). Then this derivative was used to prepare tannin-formaldehyde/phenol-formaldehyde resins (TFPF) at 20 and 40 %w/w. The kinetic values of thermal curing of phenol-formaldehyde (PF), tannin-formaldehyde and tannin-formaldehyde/phenol-formaldehyde resins (TFPF) at 20 and 40 wt% from TF were studied by monitoring the weight changes which occurred in the samples weight during thermosetting process at four temperature (160°C, 180°C, 200°C and 220°C). The total evolved condensation products from curing reactions were about 32% - 36% per sample weight, and the rate of curing reaction constants was ranged between 0.163 %wt·min-1 at 160°C and 0.50 %wt·min-1 at 220°C. The path of TFPF curing and kinetic values indicated that these resins could be cured with the behavior and velocity comparable to that of PF. The activation energy of TFPF cross-linking was higher than that of PF. Increasing TF level to 20% and 40% into PF can reduce the amount of PF curing reactions density and weight loss percentage. The global kinetic properties showed that the TF participated in the thermoset network formation with acceptable activity and performance. The general results of this paper show that the TF is a suitable alternative material for partially replacement into PF resin.

关键词： phenol-formaldehyde Tannin-formaldehyde Curing Reactions Weight Loss Monitoring Kinetic Properties

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NaOH and Ba(OH)_2 Compound Catalyzed phenolResorcinol-formaldehyde Copolycondensation Resin Adhesive for Recombined Bamboo

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Journal of Wuhan University of Technology(Materials Science) 2019年第2期34卷 459-464页

作者：左迎峰 LIU Wenjie XIAO Junhua LI Xianjun ZHAO Xing 吴义强 College of Materials Science and Engineering Central South University of Forestry and Technology Hunan Provincial Collaborative Innovation Center for High-efficiency Utilization of Wood and Bamboo Resources Central South University of Forestry and Technology

In order to reduce the curing temperature, shorten the curing time of phenol-formaldehyde(PF) resin adhesive, and ensure the good water-solubility, NaOH and Ba(OH)_2 were used as compound catalysts. The influences of the adding time of Ba(OH)_2, the adding amount of NaOH, Ba(OH)_2 and resorcinol on the properties of adhesives were studied. The properties of NaOH catalyzed phenol-formaldehyde(PF) adhesive, NaOH and Ba(OH)_2 compound catalyzed PF adhesive, NaOH and Ba(OH)_2 compound catalyzed phenol-resorcinol-formaldehyde(PRF) adhesive, and the prepared recombinant bamboo with three kinds of adhesives were compared. The experimental results show that NaOH and Ba(OH)_2 compound catalyst not only shortens the curing time of PF adhesive, but also guarantees the suitable water solubility of adhesive. After copolycondensation with resorcinol, the curing time of adhesive is further shortened, the water solubility is improved obviously, and the highest bonding strength is obtained. Infrared spectrum analysis shows that the reaction activity point of NaOH and Ba(OH)_2 compound catalyzed PRF adhesive will increase, so that both the curing temperature and curing enthalpy decrease.

关键词： phenol-formaldehyde resin NaOH,Ba(OH)2 compound catalytic resorcinol recombined bamboo

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LARIX GMELINI TANNIN-BASED ADHESIVE FOR PLYWOOD

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Journal of Northeast Forestry University 1994年第3期5卷 65-68页

作者：卢跃斌史强陈俊高振中 1. Northeast Forestry University China 2. Xinlin Forest Bureau Heilongjiang Province 3. Notheast Foresty University China

Larix tannin-phenol-formaldehyde (TPF) adhesive, having 60% by weight of phenol bcing replaced, was evaluated for its utilization in plywood. The kinetic characteristic of the TPF resin was investigated through differential scanning calorimetry (DSC) and the results obtained from the DSC scans show that the resin has a little bit different thermochemical behavior from that of phenol-formaldehyde (PF) resin. Two kinds of plywood panels wcre produced using the TPF adhesive in laboratory. The desired test results met the Chinese GB 9846-88 and ZB B70006-88, respectively, and the long assembly time of TPF resin in preparing plywood can be improved by mixing with the *** the properties of plywoods bonded with the TPF adhesive were compared with those obtaincd with synthetic PF adhesive.

关键词： Larix gmelini Tannin-phenol-formaldehyde phenol-formaldehyde Differential scanning calorimetry Plywood

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中国西南木质文物的微观研究及加固处理

中国西南木质文物的微观研究及加固处理

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北京粘接学会第二十三届学术年会暨粘接剂、密封剂技术发展研讨会

作者：邱坚伍建玲罗蓓 Monlin Kuo 西南林业大学爱荷华州立大学

Thousands of waterlogged wood pillars beneath crop fields were discovered during the2008 excavation of a 3,000 years archaeological site in Southwestern *** segment of wood pillarwas sampled in 2009 for *** were studied with scanning and transmission electron microscopes,and 2.5 cm x 2.5 cm x 5 cm(length) specimens were dehydrated with methanol,followed bytreatment with low-molecular-weight neutral phenol-formaldehyde *** wood,identified to hePinuskesiya ***(***.) Gaussen,was severely degraded by bacterial surface erosion and tunneling of cell *** tunneling was more frequently observed near the cell corners with thick *** degradation of cell walls was accompanied by accumulation of degradation products and bacterial slime in cell *** brown-rot nor soft-rot decay was detected in the *** fungi were found in rays and in adjacent tracheids,which are believed to be pre-existing prior to *** wood sample gradually darkened after sampling,but removal of bacterial degradation products with methanol and a brief 2%oxalic acid treatment reversed the *** average specific gravity and crushing strength of the waterlogged wood were 0.245 and 7.14 MPa,compared to 0.370 and 33.65 MPa of normal wood of the same *** of the waterlogged wood with neutral PF resin increased specific gravity to 0.435 and crushing strength to 12.75 *** PF treatment minimized shrinkage and warping and stabilized wood color of the waterlogged *** the PF treatment is not reversible,the treated wood remains porous to allow retreatment.

关键词： Waterlogged wood bacterial degradation microscopy phenol-formaldehyde discoloration

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