We studied the effects of nanoparticles of organo-silane（NOS） compounds in the size range of20–80 nm on physical and mechanical properties in medium density fiberboard,and used NOS at four consumption levels of 0,5...We studied the effects of nanoparticles of organo-silane（NOS） compounds in the size range of20–80 nm on physical and mechanical properties in medium density fiberboard,and used NOS at four consumption levels of 0,50,100,and 150 g kg-1dry wood fibers.Density of all treatments was kept constant at 0.67 g cm-3.The water-repellent property of organo-silane significantly reduced water absorption（WA） and thickness swelling but mechanical properties declined due to the reduced proportion of wood-fiber as organo-silane was added to the matrix：the compression ratio of MDF panels and the integrity among wood-fibers both declined,resulting in reduced mechanical properties.We recommend use of 50 g of NOS/kg wood-fiber to improve WA and thickness swelling while retaining acceptable mechanical properties.展开更多
White rot fungi were optimized to cultivate highly active laccase. The characteristics of laccase incubated by continuous culture were compared with those of direct culture. The enzyme activity of laccase incubated by...White rot fungi were optimized to cultivate highly active laccase. The characteristics of laccase incubated by continuous culture were compared with those of direct culture. The enzyme activity of laccase incubated by continuous culture technology reached a higher value on the fifth day of the growth. The optimization incubation time of high activity laccase was the eleventh day. A large amount of highly active laccase can be obtained in a relatively short time by continuous culture to replace traditional laccase. After laccase treatment, the lignin composition of wood fibers were oxidation-catalyzed by laccase. The number of chemical-bonding points between the wood fibers was increased. The wood fibers treated by laccase were fabricated into boards and their mechanical properties improved with the laccase-incubation times. Compared with the fiberboards made from fibers that were pre-treated by laccase of incubation 5 days, the static bending strength of those that were pre-treated by laccase of incubation 11 days was increased by 18.95%, the elastic modulus was increased by 35.49%, and the internal bond strength was increased by 44.11%.展开更多
Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic characte...Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.展开更多
Medium density fiberboard (MDF) is a highly competitive wooden material especially in office furniture industry. Damage and failure occur frequently in MDF due to low mechanical properties. In the present work, a modi...Medium density fiberboard (MDF) is a highly competitive wooden material especially in office furniture industry. Damage and failure occur frequently in MDF due to low mechanical properties. In the present work, a modification was performed to enhance fracture properties of MDF. The MDF plate/core was inserted into two layers (face sheet) of glass fiber composite laminates using hand layup technique. Face sheet/core delamination involves the separation of a face sheet from the core material in a sandwich MDF. Therefore, delamination test using double cantilever beam (DCB) specimen was carried out. The test measured the debonding fracture toughness (GIC) or separation strength between face sheet material (glass fiber/epoxy laminates) with MDF core material. The test is based on compliance strategy measuring fracture toughness (GIC). It was found that the fracture toughness was increased. Extended finite element model (XFEM) based on virtual crack closer technique (VCCT) was constructed to simulate the delamination behaviors of face sheet/core materials. The model results were in good agreement with the experimental ones.展开更多
In the present study,described that preparation of oligoesterified wood fibre by theaddition reaction of the wood fibre with maleic anhydride(MA)and allyl glycidyl ether(AGE).Further,made of crosslinkable oligoesterif...In the present study,described that preparation of oligoesterified wood fibre by theaddition reaction of the wood fibre with maleic anhydride(MA)and allyl glycidyl ether(AGE).Further,made of crosslinkable oligoesterified fiber board at high temperature and underhigh pressues,accompanying plasticization of the wood fibre components.The product exhibitedthe high the modulus of repture in bending(MOR),good water repellency and dimesionalstability.展开更多
为探究中密度纤维板(medium density fiberboard,MDF)板坯密度及含水率对连续压机入口段热压板间距误差的影响,进行7.7 mm(薄板)与16 mm(厚板)MDF板坯密度及含水率对入口段4个热压位置的热压板间距误差的相关试验,并结合2种纤维板板坯在...为探究中密度纤维板(medium density fiberboard,MDF)板坯密度及含水率对连续压机入口段热压板间距误差的影响,进行7.7 mm(薄板)与16 mm(厚板)MDF板坯密度及含水率对入口段4个热压位置的热压板间距误差的相关试验,并结合2种纤维板板坯在第1个热压位置的实际生产情况,分别建立板坯密度与含水率对热压板间距误差影响的预测模型。试验结果表明,热压板间距误差与2种板坯的密度呈正相关,与含水率呈负相关。2个模型预测值的相对误差均在5%以内,预测效果良好,能够有效地预测出不同板坯密度与含水率引起的热压板间距误差,研究结果为热压工艺中板坯厚度的精准控制提供一定的借鉴和参考。展开更多
基金conducted as a joint research projectfinanced by SRTTU(Iran)UPM(Malaysia)
文摘We studied the effects of nanoparticles of organo-silane（NOS） compounds in the size range of20–80 nm on physical and mechanical properties in medium density fiberboard,and used NOS at four consumption levels of 0,50,100,and 150 g kg-1dry wood fibers.Density of all treatments was kept constant at 0.67 g cm-3.The water-repellent property of organo-silane significantly reduced water absorption（WA） and thickness swelling but mechanical properties declined due to the reduced proportion of wood-fiber as organo-silane was added to the matrix：the compression ratio of MDF panels and the integrity among wood-fibers both declined,resulting in reduced mechanical properties.We recommend use of 50 g of NOS/kg wood-fiber to improve WA and thickness swelling while retaining acceptable mechanical properties.
基金funded by National Natural Science Foundation of China(31170515)Specialized Research Fund for the Doctoral Program of Higher Education of China(20130062110012)Undergraduate Training Program for Innovation and Entrepreneurship of Northeast Forestry University,China(201410225157)
文摘White rot fungi were optimized to cultivate highly active laccase. The characteristics of laccase incubated by continuous culture were compared with those of direct culture. The enzyme activity of laccase incubated by continuous culture technology reached a higher value on the fifth day of the growth. The optimization incubation time of high activity laccase was the eleventh day. A large amount of highly active laccase can be obtained in a relatively short time by continuous culture to replace traditional laccase. After laccase treatment, the lignin composition of wood fibers were oxidation-catalyzed by laccase. The number of chemical-bonding points between the wood fibers was increased. The wood fibers treated by laccase were fabricated into boards and their mechanical properties improved with the laccase-incubation times. Compared with the fiberboards made from fibers that were pre-treated by laccase of incubation 5 days, the static bending strength of those that were pre-treated by laccase of incubation 11 days was increased by 18.95%, the elastic modulus was increased by 35.49%, and the internal bond strength was increased by 44.11%.
文摘Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.
文摘Medium density fiberboard (MDF) is a highly competitive wooden material especially in office furniture industry. Damage and failure occur frequently in MDF due to low mechanical properties. In the present work, a modification was performed to enhance fracture properties of MDF. The MDF plate/core was inserted into two layers (face sheet) of glass fiber composite laminates using hand layup technique. Face sheet/core delamination involves the separation of a face sheet from the core material in a sandwich MDF. Therefore, delamination test using double cantilever beam (DCB) specimen was carried out. The test measured the debonding fracture toughness (GIC) or separation strength between face sheet material (glass fiber/epoxy laminates) with MDF core material. The test is based on compliance strategy measuring fracture toughness (GIC). It was found that the fracture toughness was increased. Extended finite element model (XFEM) based on virtual crack closer technique (VCCT) was constructed to simulate the delamination behaviors of face sheet/core materials. The model results were in good agreement with the experimental ones.
文摘In the present study,described that preparation of oligoesterified wood fibre by theaddition reaction of the wood fibre with maleic anhydride(MA)and allyl glycidyl ether(AGE).Further,made of crosslinkable oligoesterified fiber board at high temperature and underhigh pressues,accompanying plasticization of the wood fibre components.The product exhibitedthe high the modulus of repture in bending(MOR),good water repellency and dimesionalstability.
文摘为探究中密度纤维板(medium density fiberboard,MDF)板坯密度及含水率对连续压机入口段热压板间距误差的影响,进行7.7 mm(薄板)与16 mm(厚板)MDF板坯密度及含水率对入口段4个热压位置的热压板间距误差的相关试验,并结合2种纤维板板坯在第1个热压位置的实际生产情况,分别建立板坯密度与含水率对热压板间距误差影响的预测模型。试验结果表明,热压板间距误差与2种板坯的密度呈正相关,与含水率呈负相关。2个模型预测值的相对误差均在5%以内,预测效果良好,能够有效地预测出不同板坯密度与含水率引起的热压板间距误差,研究结果为热压工艺中板坯厚度的精准控制提供一定的借鉴和参考。
