To clarify liquefaction ratios and their construction variations of the main chemical compositions of wood in phenol using phosphoric acid as a catalyst, the chemical ingredients of wood such as holocellulose, cellulo...To clarify liquefaction ratios and their construction variations of the main chemical compositions of wood in phenol using phosphoric acid as a catalyst, the chemical ingredients of wood such as holocellulose, cellulose and lignin, were measured and extracted according to GB methods. With Fourier transform infrared （FTIR）, the product identification of reactant before and after liquefaction in phenol was investigated. The molecular weights and their distributions of the liquefaction results （acetone soluble parts） were studied by gel permeation chromatography （GPC）. Results show that the molecular weights and their distributions of poplar and Chinese fir are almost the same. In poplar, the distribution of cellulose is the largest, and that ofholocellulose the smallest after liquefaction. For Chinese fir, the distribution of holocellulose is the largest, and that of cellulose the smallest. After liquefaction of poplar cellulose, the change bands of FTIR spectrum observed below 1 600 cm^-1, can be attributed to new substitute groups. The same is true for poplar lignin. For Chinese fir, the spectra of liquefaction results of all chemical compositions differ from that of wood meal. This reveals the more activity groups were produced because of the reactions between Chinese fir and phenol. The research shows that the liquefaction ratios of poplar decrease in the following order： holocellulose 〉 lignin 〉 cellulose, and those of Chinese fir in the order： lignin 〉 cellulose 〉 holocellulose.展开更多
To investigate value in use of liquefied wood-based resin applications in molding material, Chinese fir （Cunninghamia lanceolata） and poplar （Populus tomentosa） wood meal were liquefied in phenol. The reactant was...To investigate value in use of liquefied wood-based resin applications in molding material, Chinese fir （Cunninghamia lanceolata） and poplar （Populus tomentosa） wood meal were liquefied in phenol. The reactant was co-condensed with formaldehyde to obtain liquefied wood-based resin. For this paper, we investigated the characterization of the resin and its application in molding material. The result shows that the basic properties of liquefied wood-based resin were satisfactory; the bonding strength of plywood prepared with liquefied Chinese fir and liquefied poplar resin can reach 1.54 and 1.00 MPa, respectively. The compression strengths of the molding material prepared with two kinds of liquefied wood resin were 73.01 and 73.58 MPa, almost the same as that of PF resin molding material. The limiting volume swelling of molding material made with liquefied Chinese resin and liquefied poplar resin were 8.5% and 8.3%, thickness swelling rates of water absorption were 3.3% and 4.2%, and the maximum weight ratios of water absorption were 25.9% and 26.2%, respectively. The soil burial test result shows that the weight loss rate of the molding materials made with liquefied Chinese resin and liquefied poplar resin were 8.3% and 9.1% and that of the PF resin molding material was 7.9%. After the soil internment test, the reduction ratio of compression strength of the two kinds of molding material achieved 16.9% and 17.7%, while that of the PF resin molding material was 15.4%. The test results of wood fungi inoculation on the three surfaces of the molding material indicate the breeding rate of molding material prepared with liquefied Chinese resin and liquefied poplar resin were at level 4 and that of PF resin molding material was at level 1 of the ISO standard.展开更多
We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modifi...We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modification solutions composed of phe- nol-melamine-formaldehyde （PMF） co-condensed resin, diatomite, and 3-aminopropyl （diethoxy） methylsilane. We measured the weight percent gain （WPG）, bulking, leaching, anti-swelling efficiency （ASE）, wa- ter-repellent effectiveness （WRE）, and oxygen index of the modified specimens. All of the wood physical properties, which are beneficial for human uses, were significantly improved by the treatment. We improved various characteristics of wood and the oxygen index of poplar above 48.6% after the modification using diatomite and PMF co-condensed resin.展开更多
Hem-fir plywood were exposed to two brown rot fungi, Gloeophyllum trabeum and Postia placenta, and one white rot fungus, Trametes versicolor, to investigate the effect of fungal decay on mechanical properties of plywo...Hem-fir plywood were exposed to two brown rot fungi, Gloeophyllum trabeum and Postia placenta, and one white rot fungus, Trametes versicolor, to investigate the effect of fungal decay on mechanical properties of plywood. Results showed that modulus of rupture （MOR） and modulus of elasticity （MOE） of hem-fir plywood declined significantly by inoculating fungi, and weight loss of sample had a modest decrease. The fungi also made a greater effect on MOR than on MOE. Of three fungi, Postia placenta caused a most significant weight loss, and Gloeophyllum trabeum resulted in a largest flexural properties loss. Substantial declines in MOR and MOE of hem-fir plywood were also observed when the plywood samples were stored under wet conditions over 15 weeks, even in the absence of fungal attack.展开更多
Theaim of the present work wasto analyze moisture flow and moisture content data for high-temperature drying by usingan advanced image- processing algorithm.Since wood starts to shrink below the fibre saturation point...Theaim of the present work wasto analyze moisture flow and moisture content data for high-temperature drying by usingan advanced image- processing algorithm.Since wood starts to shrink below the fibre saturation point during drying, the size and shape of wood will change. The dry wood image was thoroughly transformed to the shape of the wet wood image prior to calculating the dry weight moisture content. The use of the image- processing algorithm for the dry weight moisture content on density data from the CT-scanning during drying in a controlled high-temperature environment showed that this method is a powerful tool for analyzing the moisture flow inside the wood piece. Furthermore, the new CT-scanner together with the climate chamber gave unique results, as it has not been possible to study high-temperature drying with this method before.展开更多
There are many methods to identify and recognize the molecular and behavioural differences between organisms.One of the methods for the detection and identification of unknown organisms as well as intermolecular and i...There are many methods to identify and recognize the molecular and behavioural differences between organisms.One of the methods for the detection and identification of unknown organisms as well as intermolecular and intramolecular structural differences is MALDI-TOF mass spectrometry.Therefore,differentiation of Fomes fomentarius decay capabilities on the chemical properties of the wood cell wall of the tree species Quercus castaneifolia,Juglans regia,and Carpinus betulus were used to determine and characterize the destructive behaviour of F.fomentarius decay by MALDI-TOF mass spectrometry.The results showed that the fungus had more significant destructive behaviour on J.regia than the other species.For this evidence,completely removal of xylan hemicellulose fragment+Na+at peak 1227 Da and severe digestion of fragment of glucomannan hemicellulose at peak 1477–1480 Da that it seems that signs of soft-rot patterns were obtained from the decayed sample of J.regia,while these were incremental and unchanged for C.betulus and Q.castaneifolia,respectively.However,C.betulus had different peaks of atomic mass than J.regia and Q.castaneifolia wood,respectively.These results showed that this technique could be useful for separating and identifying unknown compounds of the wood cell wall attacked by fungi relying on their biological behaviour.展开更多
The performance of engineered wood products is highly associated with proper bonding and an efficient cutting method.This paper investigates the influence of CO_(2) laser cutting on the wetting properties,the modified ch...The performance of engineered wood products is highly associated with proper bonding and an efficient cutting method.This paper investigates the influence of CO_(2) laser cutting on the wetting properties,the modified che-mical component of the laser-cut surface,and the strength and adhesive penetration near the bondline.Beech-wood is cut by the laser with varying processing parameters,cutting speeds,gas pressures,and focal point positions.The laser-cut samples were divided into two groups,sanded and non-sanded samples.Polyvinyl acetate adhesive(PVAc)was used to bond the groups of laser-cut samples.After assembly with cold pressing,the tensile shear test was carried out.Numerical modelling was carried out to determine the partial elongation and shear strain of the glue line.Based on this,the shear modulus and linear elasticity of the glue line were estimated.Scan-ning electron microscopy was used to assess the adhesive penetration into the porosity structure of the laser-cut samples,and the depth of the heat-affected zone.The laser-cut surface was analysed by Fourier transform infrared spectroscopy.The wetting properties of the laser-cut surface were investigated by using a contact angle goni-ometer.The numerical model of the strain-stress curve confirmed the experimental model.The highest modulus of the linear elasticity of the glue in the numerical calculation belongs to the joint containing laser-cut samples at a gas pressure of 21(bar).The penetration depth of PVAc adhesive into the porosity structure of the laser-cut sam-ples was similar to that of sawn samples.The deepest heat-affected zone in the laser-cut samples was 150µm.A PVAc drop disappeared immediately on the laser-cut surface without sanding,but gradually on the sanded surface.In contrast,the drop on the sawn surface remained with an angle of 32°–48°.The degradation of hemi-cellulose and lignin was proven by the lower intensity of the C=O and C-O Bonds,compared to the sawn surface.展开更多
Magnetic properties of composites prepared by coating lacquer containing neodymium iron boron （Nd-Fe-B） powders on rubberwood were characterized by vibrating sample magnetometry （VSM）, magnetic moment measurements...Magnetic properties of composites prepared by coating lacquer containing neodymium iron boron （Nd-Fe-B） powders on rubberwood were characterized by vibrating sample magnetometry （VSM）, magnetic moment measurements, and attraction tests with an iron-core solenoid. The Nd-Fe-B powders were recycled from electronic wastes by the ball-milling technique. Varying the milling time from 20 to 300 min, the magnetic squareness and the coercive field of the Nd-Fe-B powders were at the minimum when the powders were milled for 130 rain. It followed that the coercive field of the magnetic wood composites was increased with the milling time increasing from 130 to 300 min. For the magnetic wood composites using Nd-Fe-B obtained from the same milling time, the magnetic squareness and the coercive field were rather insensitive to the variation of Nd-Fe-B concentration in coating lacquer from 0.43 to 1.00 g/cm3. By contrast, the magnetization and magnetic moment were increased with the Nd-Fe-B concentration increasing. Furthermore, the electrical current in the solenoid required for the attraction of the magnetic wood composites was exponentially reduced with the increase in the amount of Nd-Fe-B used in the coating.展开更多
The purpose of this research study was to investigate the properties of polyurethane coatings based on lignin nano-particles.For this purpose,the prepared coatings were applied to pine wood surfaces and weathered arti...The purpose of this research study was to investigate the properties of polyurethane coatings based on lignin nano-particles.For this purpose,the prepared coatings were applied to pine wood surfaces and weathered artificially.Subsequently,color and gloss of the coatings were measured before and after the weathering test.Field emission scanning electron microscopy(FE-SEM)micrographs prepared from the coatings showed that the average size of nano-particles in the polyurethane substrate was approximately 500 nm.Nuclear magnetic resonance(13C-NMR)spectroscopy showed that strong urethane bonds were formed in the nano-lignin-based polyurethane.Differential calorimetric analysis(DSC)test revealed that the glass-transition temperature(Tg)of lignin nanoparticles modified with diethylenetriamine(DETA)was 112.8℃ and Tg of lignin nano-particles modified with ethylenediamine(EDA)was 102.5℃,which is lower than the Tg of un-modified lignin(114.6℃)and lignin modified with DETA(126.8℃)and lignin modified with EDA(131.3℃).The coatings modified with lignin nano-particles had a greater change in gloss.The lignin nano-particles in the modified coating are trapping hydroxyl radicals which reduces photoactivity and yellowing of the polyurethane by about 3 times compared to unmodified polyurethane coatings.After weathering test,the nano-lignin-based coating had a rougher surface with a lower contact angle(0.78°)compared to the unmodified polyurethane coating(0.85°).展开更多
Lithium-ion batteries are widely recognized as prime candidates for energy storage devices.Ethylene carbonate(EC)has become a critical component in conventional commercial electrolytes due to its exceptional film-form...Lithium-ion batteries are widely recognized as prime candidates for energy storage devices.Ethylene carbonate(EC)has become a critical component in conventional commercial electrolytes due to its exceptional film-forming properties and high dielectric constant.However,the elevated freezing point,high viscosity,and strong solvation energy of EC significantly hinder the transport rate of Li^(+)and the desolvation process at low temperatures.This leads to substantial capacity loss and even lithium plating on graphite anodes.Herein,we have developed an efficient electrolyte system specifically designed for lowtemperature conditions,which consists of 1.0 M lithium bis(fluorosulfonyl)imide(LiFSI)in isoxazole(IZ)with fluorobenzene(FB)as an uncoordinated solvent and fluoroethylene carbonate(FEC)as a filmforming co-solvent.This system effectively lowers the desolvation energy of Li^(+)through dipole-dipole interactions.The weak solvation capability allows more anions to enter the solvation sheath,promoting the formation of contact ion pairs(CIPs)and aggregates(AGGs)that enhance the transport rate of Li^(+)while maintaining high ionic conductivity across a broad temperature range.Moreover,the formation of inorganic-dominant interfacial phases on the graphite anode,induced by fluoroethylene carbonate,significantly enhances the kinetics of Li^(+)transport.At a low temperature of-20℃,this electrolyte system achieves an impressive reversible capacity of 200.9 mAh g^(-1)in graphite half-cell,which is nearly three times that observed with conventional EC-based electrolytes,demonstrating excellent stability throughout its operation.展开更多
Traditional formaldehyde-based adhesives rely excessively on petrochemical resources,release toxic gases,and pollute the environment.Plant-derived soybean protein adhesives are eco-friendly materials that have the pot...Traditional formaldehyde-based adhesives rely excessively on petrochemical resources,release toxic gases,and pollute the environment.Plant-derived soybean protein adhesives are eco-friendly materials that have the potential to replace the formaldehyde-based adhesives used to fabricate wood-based panels.However,the poor water resistance,high brittleness,and poor mildew resistance of soybean protein adhesives limit their industrial applications.This article reviews recent research progress in the modification of soybean protein adhesives for improving the bonding performance of adhesives used for wood-based panel fabrication.Modification methods were summarized in terms of water resistance,solid content,and mildew resistance.The modification mechanisms and remaining problems were also discussed.Finally,the current industrial applications and the future research direction of soybean protein adhesives are discussed.展开更多
To extend the service life and explore the use of wood-based composites, it is quite necessary toimprove the decay resistance of wood-based composites through preservative treatments. Researchers havestudied the metho...To extend the service life and explore the use of wood-based composites, it is quite necessary toimprove the decay resistance of wood-based composites through preservative treatments. Researchers havestudied the methods of preservative treatment and the decay resistance of treated wood-based composites.In this paper, the categories of wood-based composites are briefly summarized and the previous and presentinvestigations on the preservative treatment and decay resistance of different categories of wood-basedcomposites are introduced. Some problems are also put forward and suggestions are given for future studies.展开更多
This study investigated the effects of torrefaction on forest residue(FR)and its subsequent ap-plication as a bulk-loading filler in polylactic acid(PLA)composites.Torrefaction enhanced the chemical properties of FR,i...This study investigated the effects of torrefaction on forest residue(FR)and its subsequent ap-plication as a bulk-loading filler in polylactic acid(PLA)composites.Torrefaction enhanced the chemical properties of FR,improving its compatibility with PLA,and the crystallinity increased from 24.9%to 42.5%.The process also improved the hydrophobicity of PLA/biomass composites,as demonstrated by the water contact angle of 76.1°,closely matching that of neat PLA(76.4°).With the introduction of 20%modified biomass properties after torrefaction treatment,the tensile strength of PLA/biomass composite increased from 58.7 to 62.3 MPa.Additionally,the addition of torrefied forest residue(TFR)accelerated biodegradation by increasing the onset of degrada-tion and inhibiting crystallization.After 90 d,the biodegradability of PLA/biomass composites reached 94.9%,which had a 6.9%increase compared to the neat PLA(88.8%).Overall,this study highlights the potential of torrefaction in enhancing both the physical properties and biodegrad-ability of PLA-based composites,contributing to a more sustainable approach to reducing plastic pollution.展开更多
Building construction and maintenance is one of the major contributors to global warming and as a result has the potential to be a leader in sustainable develop-ment.Scaffolding systems are an important component of b...Building construction and maintenance is one of the major contributors to global warming and as a result has the potential to be a leader in sustainable develop-ment.Scaffolding systems are an important component of building construction,especially high-rise buildings.A scaffold consists of a modular system of metal or bamboo tubes or pipes.Scaffolding is a temporary construction structure created for reaching heights above a human’s reach,with the purpose of helping in con-struction or maintenance of a structure.The scaffolding industry in the US is dominated by steel.In areas where bamboo is indigenous,like many East Asian cities,bamboo is the scaffolding material of choice,even when it comes to high-rise buildings.Our goal was to analyze bamboo and steel thoroughly and estab-lish their environmental impacts using life cycle analysis(LCA).Consequently,this study explores the ecological viability in expanding the use of bamboo scaffolding where steel predominates.The functional units used in this study are bamboo and steel scaffolding systems that are 2.74 m high,2.49 m wide,and 1.21 m deep.A cradle-to-gate LCA was performed to evaluate the environmental performance of the two scaffolding systems.Our results suggest that bamboo scaffolding has a lower carbon footprint than steel scaffolding,with an ability to sequester carbon during its growth phase being a significant contributing factor.This is an important advantage of bamboo over nonrenewable materials(steel).Additionally,bamboo functions as a buffer,delaying the release of CO_(2) after the use phase.The main challenge for any scaffolding system made from renewable materials in the western world is the demand for standardization.Therefore,an ideal future goal should be the design of standardized scaffolding systems using renewable materials that com-bines the durability and homogeneity of steel scaffolding with the sustainability and environmental performance of bamboo scaffolding.展开更多
In this study,a cradle-to-gate life-cycle assessment(LCA)of Oregon-made cross-laminated timber(CLT)was conducted as per the ISO guidelines.Primary data pertaining to CLT manufacturing was collected from a production f...In this study,a cradle-to-gate life-cycle assessment(LCA)of Oregon-made cross-laminated timber(CLT)was conducted as per the ISO guidelines.Primary data pertaining to CLT manufacturing was collected from a production facility in Oregon and modeled with existing LCA data of Pacific Northwest softwood lumber production and harvesting operations.Primary energy is reported and encompasses all processes within the system boundary.Carbon emissions are reported and include fossil-based emissions from transportation and all production processes and carbon storage in CLT.LCA results are presented for five impact categories,primary energy consumption,and net carbon impact of CLT.Results show the environmental advantage of CLT due to storing of large amounts of biogenic carbon in a building structure for a lifetime.The amount of carbon stored in CLT offsets the emissions released from all production processes;this indicates that CLT is a net negative carbon emitter,as more carbon is stored in the product than is emitted to produce the product.This study shows the importance of using the LCA methodology for showing the net amount and type of energy used for production and the potential climatic impacts of using wood products.This LCA study makes no comparative assertions.展开更多
基金Supported by the Key Research Program Foundation, Ministry of Educational of China (Grant No.02021)the National Natural Science Foundation of China (Grant No. 30471351)
文摘To clarify liquefaction ratios and their construction variations of the main chemical compositions of wood in phenol using phosphoric acid as a catalyst, the chemical ingredients of wood such as holocellulose, cellulose and lignin, were measured and extracted according to GB methods. With Fourier transform infrared （FTIR）, the product identification of reactant before and after liquefaction in phenol was investigated. The molecular weights and their distributions of the liquefaction results （acetone soluble parts） were studied by gel permeation chromatography （GPC）. Results show that the molecular weights and their distributions of poplar and Chinese fir are almost the same. In poplar, the distribution of cellulose is the largest, and that ofholocellulose the smallest after liquefaction. For Chinese fir, the distribution of holocellulose is the largest, and that of cellulose the smallest. After liquefaction of poplar cellulose, the change bands of FTIR spectrum observed below 1 600 cm^-1, can be attributed to new substitute groups. The same is true for poplar lignin. For Chinese fir, the spectra of liquefaction results of all chemical compositions differ from that of wood meal. This reveals the more activity groups were produced because of the reactions between Chinese fir and phenol. The research shows that the liquefaction ratios of poplar decrease in the following order： holocellulose 〉 lignin 〉 cellulose, and those of Chinese fir in the order： lignin 〉 cellulose 〉 holocellulose.
基金This study was financially supported by the National Natural Science Foundation of China （Grant No. 30471351）.
文摘To investigate value in use of liquefied wood-based resin applications in molding material, Chinese fir （Cunninghamia lanceolata） and poplar （Populus tomentosa） wood meal were liquefied in phenol. The reactant was co-condensed with formaldehyde to obtain liquefied wood-based resin. For this paper, we investigated the characterization of the resin and its application in molding material. The result shows that the basic properties of liquefied wood-based resin were satisfactory; the bonding strength of plywood prepared with liquefied Chinese fir and liquefied poplar resin can reach 1.54 and 1.00 MPa, respectively. The compression strengths of the molding material prepared with two kinds of liquefied wood resin were 73.01 and 73.58 MPa, almost the same as that of PF resin molding material. The limiting volume swelling of molding material made with liquefied Chinese resin and liquefied poplar resin were 8.5% and 8.3%, thickness swelling rates of water absorption were 3.3% and 4.2%, and the maximum weight ratios of water absorption were 25.9% and 26.2%, respectively. The soil burial test result shows that the weight loss rate of the molding materials made with liquefied Chinese resin and liquefied poplar resin were 8.3% and 9.1% and that of the PF resin molding material was 7.9%. After the soil internment test, the reduction ratio of compression strength of the two kinds of molding material achieved 16.9% and 17.7%, while that of the PF resin molding material was 15.4%. The test results of wood fungi inoculation on the three surfaces of the molding material indicate the breeding rate of molding material prepared with liquefied Chinese resin and liquefied poplar resin were at level 4 and that of PF resin molding material was at level 1 of the ISO standard.
基金supported by Program for New Century Excellent Talents in University(NCET-10-0311)the National Natural Science Foundation of China(31000271)the Fundamental Research Funds for the Central Universities(DL11BB29)
文摘We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modification solutions composed of phe- nol-melamine-formaldehyde （PMF） co-condensed resin, diatomite, and 3-aminopropyl （diethoxy） methylsilane. We measured the weight percent gain （WPG）, bulking, leaching, anti-swelling efficiency （ASE）, wa- ter-repellent effectiveness （WRE）, and oxygen index of the modified specimens. All of the wood physical properties, which are beneficial for human uses, were significantly improved by the treatment. We improved various characteristics of wood and the oxygen index of poplar above 48.6% after the modification using diatomite and PMF co-condensed resin.
基金This research was supported by Forest Research Labora-tory, Oregon State University
文摘Hem-fir plywood were exposed to two brown rot fungi, Gloeophyllum trabeum and Postia placenta, and one white rot fungus, Trametes versicolor, to investigate the effect of fungal decay on mechanical properties of plywood. Results showed that modulus of rupture （MOR） and modulus of elasticity （MOE） of hem-fir plywood declined significantly by inoculating fungi, and weight loss of sample had a modest decrease. The fungi also made a greater effect on MOR than on MOE. Of three fungi, Postia placenta caused a most significant weight loss, and Gloeophyllum trabeum resulted in a largest flexural properties loss. Substantial declines in MOR and MOE of hem-fir plywood were also observed when the plywood samples were stored under wet conditions over 15 weeks, even in the absence of fungal attack.
文摘Theaim of the present work wasto analyze moisture flow and moisture content data for high-temperature drying by usingan advanced image- processing algorithm.Since wood starts to shrink below the fibre saturation point during drying, the size and shape of wood will change. The dry wood image was thoroughly transformed to the shape of the wet wood image prior to calculating the dry weight moisture content. The use of the image- processing algorithm for the dry weight moisture content on density data from the CT-scanning during drying in a controlled high-temperature environment showed that this method is a powerful tool for analyzing the moisture flow inside the wood piece. Furthermore, the new CT-scanner together with the climate chamber gave unique results, as it has not been possible to study high-temperature drying with this method before.
文摘There are many methods to identify and recognize the molecular and behavioural differences between organisms.One of the methods for the detection and identification of unknown organisms as well as intermolecular and intramolecular structural differences is MALDI-TOF mass spectrometry.Therefore,differentiation of Fomes fomentarius decay capabilities on the chemical properties of the wood cell wall of the tree species Quercus castaneifolia,Juglans regia,and Carpinus betulus were used to determine and characterize the destructive behaviour of F.fomentarius decay by MALDI-TOF mass spectrometry.The results showed that the fungus had more significant destructive behaviour on J.regia than the other species.For this evidence,completely removal of xylan hemicellulose fragment+Na+at peak 1227 Da and severe digestion of fragment of glucomannan hemicellulose at peak 1477–1480 Da that it seems that signs of soft-rot patterns were obtained from the decayed sample of J.regia,while these were incremental and unchanged for C.betulus and Q.castaneifolia,respectively.However,C.betulus had different peaks of atomic mass than J.regia and Q.castaneifolia wood,respectively.These results showed that this technique could be useful for separating and identifying unknown compounds of the wood cell wall attacked by fungi relying on their biological behaviour.
文摘The performance of engineered wood products is highly associated with proper bonding and an efficient cutting method.This paper investigates the influence of CO_(2) laser cutting on the wetting properties,the modified che-mical component of the laser-cut surface,and the strength and adhesive penetration near the bondline.Beech-wood is cut by the laser with varying processing parameters,cutting speeds,gas pressures,and focal point positions.The laser-cut samples were divided into two groups,sanded and non-sanded samples.Polyvinyl acetate adhesive(PVAc)was used to bond the groups of laser-cut samples.After assembly with cold pressing,the tensile shear test was carried out.Numerical modelling was carried out to determine the partial elongation and shear strain of the glue line.Based on this,the shear modulus and linear elasticity of the glue line were estimated.Scan-ning electron microscopy was used to assess the adhesive penetration into the porosity structure of the laser-cut samples,and the depth of the heat-affected zone.The laser-cut surface was analysed by Fourier transform infrared spectroscopy.The wetting properties of the laser-cut surface were investigated by using a contact angle goni-ometer.The numerical model of the strain-stress curve confirmed the experimental model.The highest modulus of the linear elasticity of the glue in the numerical calculation belongs to the joint containing laser-cut samples at a gas pressure of 21(bar).The penetration depth of PVAc adhesive into the porosity structure of the laser-cut sam-ples was similar to that of sawn samples.The deepest heat-affected zone in the laser-cut samples was 150µm.A PVAc drop disappeared immediately on the laser-cut surface without sanding,but gradually on the sanded surface.In contrast,the drop on the sawn surface remained with an angle of 32°–48°.The degradation of hemi-cellulose and lignin was proven by the lower intensity of the C=O and C-O Bonds,compared to the sawn surface.
基金supported by Molecular Technology Research Unit, Walailak University and Department of Physics, Kasetsart University
文摘Magnetic properties of composites prepared by coating lacquer containing neodymium iron boron （Nd-Fe-B） powders on rubberwood were characterized by vibrating sample magnetometry （VSM）, magnetic moment measurements, and attraction tests with an iron-core solenoid. The Nd-Fe-B powders were recycled from electronic wastes by the ball-milling technique. Varying the milling time from 20 to 300 min, the magnetic squareness and the coercive field of the Nd-Fe-B powders were at the minimum when the powders were milled for 130 rain. It followed that the coercive field of the magnetic wood composites was increased with the milling time increasing from 130 to 300 min. For the magnetic wood composites using Nd-Fe-B obtained from the same milling time, the magnetic squareness and the coercive field were rather insensitive to the variation of Nd-Fe-B concentration in coating lacquer from 0.43 to 1.00 g/cm3. By contrast, the magnetization and magnetic moment were increased with the Nd-Fe-B concentration increasing. Furthermore, the electrical current in the solenoid required for the attraction of the magnetic wood composites was exponentially reduced with the increase in the amount of Nd-Fe-B used in the coating.
文摘The purpose of this research study was to investigate the properties of polyurethane coatings based on lignin nano-particles.For this purpose,the prepared coatings were applied to pine wood surfaces and weathered artificially.Subsequently,color and gloss of the coatings were measured before and after the weathering test.Field emission scanning electron microscopy(FE-SEM)micrographs prepared from the coatings showed that the average size of nano-particles in the polyurethane substrate was approximately 500 nm.Nuclear magnetic resonance(13C-NMR)spectroscopy showed that strong urethane bonds were formed in the nano-lignin-based polyurethane.Differential calorimetric analysis(DSC)test revealed that the glass-transition temperature(Tg)of lignin nanoparticles modified with diethylenetriamine(DETA)was 112.8℃ and Tg of lignin nano-particles modified with ethylenediamine(EDA)was 102.5℃,which is lower than the Tg of un-modified lignin(114.6℃)and lignin modified with DETA(126.8℃)and lignin modified with EDA(131.3℃).The coatings modified with lignin nano-particles had a greater change in gloss.The lignin nano-particles in the modified coating are trapping hydroxyl radicals which reduces photoactivity and yellowing of the polyurethane by about 3 times compared to unmodified polyurethane coatings.After weathering test,the nano-lignin-based coating had a rougher surface with a lower contact angle(0.78°)compared to the unmodified polyurethane coating(0.85°).
基金financial support from the Department of Science and Technology of Jilin Province(20240304104SF,20240304103SF)the Research and Innovation Fund of the Beihua University for the Graduate Student(Major Project 2023012)。
文摘Lithium-ion batteries are widely recognized as prime candidates for energy storage devices.Ethylene carbonate(EC)has become a critical component in conventional commercial electrolytes due to its exceptional film-forming properties and high dielectric constant.However,the elevated freezing point,high viscosity,and strong solvation energy of EC significantly hinder the transport rate of Li^(+)and the desolvation process at low temperatures.This leads to substantial capacity loss and even lithium plating on graphite anodes.Herein,we have developed an efficient electrolyte system specifically designed for lowtemperature conditions,which consists of 1.0 M lithium bis(fluorosulfonyl)imide(LiFSI)in isoxazole(IZ)with fluorobenzene(FB)as an uncoordinated solvent and fluoroethylene carbonate(FEC)as a filmforming co-solvent.This system effectively lowers the desolvation energy of Li^(+)through dipole-dipole interactions.The weak solvation capability allows more anions to enter the solvation sheath,promoting the formation of contact ion pairs(CIPs)and aggregates(AGGs)that enhance the transport rate of Li^(+)while maintaining high ionic conductivity across a broad temperature range.Moreover,the formation of inorganic-dominant interfacial phases on the graphite anode,induced by fluoroethylene carbonate,significantly enhances the kinetics of Li^(+)transport.At a low temperature of-20℃,this electrolyte system achieves an impressive reversible capacity of 200.9 mAh g^(-1)in graphite half-cell,which is nearly three times that observed with conventional EC-based electrolytes,demonstrating excellent stability throughout its operation.
基金the National Natural Science Foundation of China(31722011)Beijing Forestry University Outstanding Young Talent Cultivation Project(2019JQ03004)the Agricultural Science and Technology Fund Project of Shandong Province(Forestry Science and Technology Innovation)(2019LY008).
文摘Traditional formaldehyde-based adhesives rely excessively on petrochemical resources,release toxic gases,and pollute the environment.Plant-derived soybean protein adhesives are eco-friendly materials that have the potential to replace the formaldehyde-based adhesives used to fabricate wood-based panels.However,the poor water resistance,high brittleness,and poor mildew resistance of soybean protein adhesives limit their industrial applications.This article reviews recent research progress in the modification of soybean protein adhesives for improving the bonding performance of adhesives used for wood-based panel fabrication.Modification methods were summarized in terms of water resistance,solid content,and mildew resistance.The modification mechanisms and remaining problems were also discussed.Finally,the current industrial applications and the future research direction of soybean protein adhesives are discussed.
文摘To extend the service life and explore the use of wood-based composites, it is quite necessary toimprove the decay resistance of wood-based composites through preservative treatments. Researchers havestudied the methods of preservative treatment and the decay resistance of treated wood-based composites.In this paper, the categories of wood-based composites are briefly summarized and the previous and presentinvestigations on the preservative treatment and decay resistance of different categories of wood-basedcomposites are introduced. Some problems are also put forward and suggestions are given for future studies.
基金supported by the Korea Research Institute of Chemical Technology(KRICT)Project(No.KS2442-10)the R&D Program(No.20017973)of the Ministry of Trade,Industry,and Energy(MOTIE/KEIT).
文摘This study investigated the effects of torrefaction on forest residue(FR)and its subsequent ap-plication as a bulk-loading filler in polylactic acid(PLA)composites.Torrefaction enhanced the chemical properties of FR,improving its compatibility with PLA,and the crystallinity increased from 24.9%to 42.5%.The process also improved the hydrophobicity of PLA/biomass composites,as demonstrated by the water contact angle of 76.1°,closely matching that of neat PLA(76.4°).With the introduction of 20%modified biomass properties after torrefaction treatment,the tensile strength of PLA/biomass composite increased from 58.7 to 62.3 MPa.Additionally,the addition of torrefied forest residue(TFR)accelerated biodegradation by increasing the onset of degrada-tion and inhibiting crystallization.After 90 d,the biodegradability of PLA/biomass composites reached 94.9%,which had a 6.9%increase compared to the neat PLA(88.8%).Overall,this study highlights the potential of torrefaction in enhancing both the physical properties and biodegrad-ability of PLA-based composites,contributing to a more sustainable approach to reducing plastic pollution.
文摘Building construction and maintenance is one of the major contributors to global warming and as a result has the potential to be a leader in sustainable develop-ment.Scaffolding systems are an important component of building construction,especially high-rise buildings.A scaffold consists of a modular system of metal or bamboo tubes or pipes.Scaffolding is a temporary construction structure created for reaching heights above a human’s reach,with the purpose of helping in con-struction or maintenance of a structure.The scaffolding industry in the US is dominated by steel.In areas where bamboo is indigenous,like many East Asian cities,bamboo is the scaffolding material of choice,even when it comes to high-rise buildings.Our goal was to analyze bamboo and steel thoroughly and estab-lish their environmental impacts using life cycle analysis(LCA).Consequently,this study explores the ecological viability in expanding the use of bamboo scaffolding where steel predominates.The functional units used in this study are bamboo and steel scaffolding systems that are 2.74 m high,2.49 m wide,and 1.21 m deep.A cradle-to-gate LCA was performed to evaluate the environmental performance of the two scaffolding systems.Our results suggest that bamboo scaffolding has a lower carbon footprint than steel scaffolding,with an ability to sequester carbon during its growth phase being a significant contributing factor.This is an important advantage of bamboo over nonrenewable materials(steel).Additionally,bamboo functions as a buffer,delaying the release of CO_(2) after the use phase.The main challenge for any scaffolding system made from renewable materials in the western world is the demand for standardization.Therefore,an ideal future goal should be the design of standardized scaffolding systems using renewable materials that com-bines the durability and homogeneity of steel scaffolding with the sustainability and environmental performance of bamboo scaffolding.
基金the USDA National Institute of Food and Agriculture’s UW-SEFS McIntire-Stennis grant,project no.WNZ-04162015-GE-Accession No.1006435,for funding this this work.
文摘In this study,a cradle-to-gate life-cycle assessment(LCA)of Oregon-made cross-laminated timber(CLT)was conducted as per the ISO guidelines.Primary data pertaining to CLT manufacturing was collected from a production facility in Oregon and modeled with existing LCA data of Pacific Northwest softwood lumber production and harvesting operations.Primary energy is reported and encompasses all processes within the system boundary.Carbon emissions are reported and include fossil-based emissions from transportation and all production processes and carbon storage in CLT.LCA results are presented for five impact categories,primary energy consumption,and net carbon impact of CLT.Results show the environmental advantage of CLT due to storing of large amounts of biogenic carbon in a building structure for a lifetime.The amount of carbon stored in CLT offsets the emissions released from all production processes;this indicates that CLT is a net negative carbon emitter,as more carbon is stored in the product than is emitted to produce the product.This study shows the importance of using the LCA methodology for showing the net amount and type of energy used for production and the potential climatic impacts of using wood products.This LCA study makes no comparative assertions.
