Cement-bonded particleboards of 6 mm in thickness were manufactured using maize stalk （Zea mays） particles of uniform sizes at three levels of board density and additive concentrations respectively. The bending stre...Cement-bonded particleboards of 6 mm in thickness were manufactured using maize stalk （Zea mays） particles of uniform sizes at three levels of board density and additive concentrations respectively. The bending strength and dimensional properties were assessed. Increase in board density and additive concentration caused increase in Modulus of rupture （MOR）, Modulus of elasticity （MOE）, and decrease in Thickness swelling （TS） and Water absorption （WA）. The MOR, MOE and TS of the boards were significantly affected by board density except for WA, but additive concentration affected all the boards＇ properties examined at p ≥ 0.05. Strong and dimensional stable cement-bonded boards could be manufactured from maize stalk particles with Portland cement as the binder after hot water treatment. Although the dimensional stability and mechanical strength properties of the boards were affected by the board density and additive concentration, the study revealed that cement-bonded particleboards could be manufactured from maize stalk （Zea mays） particles. However, the increase in board density and additive concentration could cause the increase in MOR and MOE, and cause the decrease in TS and WA of boards.展开更多
Lignocellulosic residues resulting from agricultural activities and urban centers cause pollution. A possible solution to this problem is to combine these residues with woody plants to produce particleboards. The purp...Lignocellulosic residues resulting from agricultural activities and urban centers cause pollution. A possible solution to this problem is to combine these residues with woody plants to produce particleboards. The purpose of this study was to evaluate decay resistance, coating and burning properties and the change of color caused by accelerated weathering of particleboards manufactured with a combination of 3 woody species used for commercial reforestation in tropical areas (Cupressus lusitanica, Gmelina arborea and Tectona grandis), pineapple (Ananas comosus) leaves from the crown and the plant (PL), empty fruit bunch of Elaeis guineensis (EBF) and tetra pak packages (TP). According to the results, the mixtures of T. grandis and EFB were classified as moderately resistant and other mixtures (woody species and PL or TP) were classified as slightly resistant. The finish performance test determined that the mixtures with TP presented the best performance, followed by the mixtures with oil palm components and the mixtures composed of pineapple leaves. Regarding lacquer consumption, no differences were found between the mixtures. The combustion test determined that particleboards with TP and EFB showed the highest resistance to combustion, while pineapple presented the lowest resistances to combustion. In the accelerated weathering exposure test, the mixtures of the three species with TP showed the best performance in accelerated weathering. Contrariwise, the mixtures with pineapple leaves showed the lowest resistance to accelerated weathering. Oil palm particleboards presented lower resistance to weathering than TP, though higher than pineapple leaves’ resistance.展开更多
Using 1–8 years bamboo as materials,the content of different chemical constituent was tested,and the reactive oxygen species(ROS)free radicals produced from laccase treated bamboo were detected by electron spin-reson...Using 1–8 years bamboo as materials,the content of different chemical constituent was tested,and the reactive oxygen species(ROS)free radicals produced from laccase treated bamboo were detected by electron spin-resonance(ESR)spectroscope.The wet-process particleboard was made from laccase-treated bamboo by hot pressing and board mechanical properties including internal bond strength(IB),modulus of rupture(MOR)and thickness swelling(TS)after 2-hours water absorption were tested under different conditions.Results showed that laccase mainly catalyze the bamboo components and improved the bonding strength of laccase-treated boards.By ESR measurement on each single component such as milled bamboo lignin,xylan and pore cotton treated with laccase,it was proved that laccase helped the degradation of bamboo lignin to produce ROS free radicals and could not catalyze the oxidation of cellulose and hemicelluloses.A logarithmic function relationship was found between board mechanical properties and ROS free radical level.It is optimal to using 5-year-old bamboo for high efficient utilization.The laccase treatment improves the activity of bamboo particles participating in self-adhesion reaction.展开更多
Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue ...Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue for particleboard production. This study assessed the decay resistance of particleboards produced from four agro-forest residues using cassava starch and urea formaldehyde as adhesives. <i><span>Musa paradisiaca pseudostem</span></i><span>, </span><i><span>Theobroma cacao </span></i><span>stem and pod, and sawdust of </span><i><span>Ceiba pentandra</span></i><span> were used for the study. Properties determined were: Weight loss, decay resistance rating and decay susceptibility index. These properties were evaluated after 12 weeks of exposure to </span><i><span>Coriolopsis polyzona</span></i><span> in accordance with ASTM D 2017</span><span>-</span><span>05. The results indicate that the weight loss for </span><i><span>Musa paradisiaca pseudostem</span></i><span> particleboard was least for both urea formaldehyde and cassava starch adhesives. Even though almost all the particleboards produced were classified as resistant or highly resistant to fungi attack, those produced with urea formaldehyde had better decay resistance properties than that of cassava starch. Furthermore, particleboards coated with synthetic polyvinyl lacquer had better resistance to fungi attack than the uncoated ones. At 5% level of significance, the agro-forest residue, adhesive and surface finish as well as their interactions had significant effects on decay resistance of the particleboards produced. It is recommended that further studies which aim at determining the effect of combination of the agro-forest residues and that of urea formaldehyde and cassava starch be conducted to determine their effects on decay properties of particleboards.</span>展开更多
This work contributes to the use of alternative adhesives in the wood-based industry,where pine wood is commonly used.The investigation identifies the influence and the optimal content(8,12 and 15wt%)of a bio-based po...This work contributes to the use of alternative adhesives in the wood-based industry,where pine wood is commonly used.The investigation identifies the influence and the optimal content(8,12 and 15wt%)of a bio-based polyurethane adhesive in the production of medium density particleboards(MDP).A compaction pressure of 4 MPa at 100oC for 10 minutes is considered in the manufacture of panels based on pine wood residues and bio-based resin.The bulk density,flexural modulus(MOE)and strength(MOR)properties under static three-point bending are obtained according to the Brazilian standard NBR 14810.The results are compared with NBR 14810 and other standards to verify its performance based on the minimum requirements.Bulk density is not significantly affected by the investigated adhesive levels.MOE and MOR reach average values equivalent to 12wt%and 15wt%of the adhesive,and both meet the minimum requirements established in international normative documents.The adhesive level range responsible for maximizingρ,MOE and MOR is between 12.42wt%and 15.79wt%.展开更多
The utilization of oil palm biomass in the production of high-value products has increased substantially.Due to the presence of sugars and starches in their tissues,oil palms have an exceptionally low natural resistan...The utilization of oil palm biomass in the production of high-value products has increased substantially.Due to the presence of sugars and starches in their tissues,oil palms have an exceptionally low natural resistance to fungi,making them susceptible to contamination.In this study,the properties of particleboard made from oil palmfibers,namely empty fruit bunches(EFB),oil palm trunks(OPT),and oil palm fronds(OPF)fibers and its poten-tial for fungal attack were evaluated.The chemical composition,spectroscopic characterization,morphological features,and elemental analysis of oil palm biomassfibers were identified and thoroughly examined.The mechan-ical properties and dimensional stability of the boards were assessed based on Japanese Industrial Standards(JIS)and American National Standards Institute(ANSI)guidelines.The density,strength,and moisture resistance of particleboard made from OPTfibers may vary from those made from OPF and EFB due to inherent changes in chemical composition andfiber structure.These differences have an impact on the overall performance of the particleboard.Based on the ANOVA and Tukey’s test results,significant differences in elasticity properties were observed mainly between OPT and otherfibers,while bending strength revealed notable differences between various pairs of particleboards.The evaluation also highlighted variations in dimensional stability and water absorption capabilities.However,bending strength properties did not demonstrate any significant deviations.For the fungi test,fungal activity on the boards was observed over a two-week period in a controlled environment.The study revealed that oil palm-based particleboard exhibited susceptibility to fungal attacks,particularly from Aspergillus sp.,Trichoderma sp.,and Paecilomyces variotii.Thesefindings highlight the necessity for additional treatments to control or prevent fungal growth,thereby enhancing the commercial value of the particleboards.展开更多
Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics ...Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics of particleboards were compared to that of ultralow emitting formaldehyde(ULEF-UF).Thefillers derived from Eucalyptus spp.kraft-lignin were added forflame retardancy enhancement.10%of each lignin and modified lig-nin was added into the ULEF-UF and citric acid-sucrose bonded particleboards.Analyses applied to particle-boards included thermal characteristics,X-ray diffraction analysis(XRD),morphological properties,Fourier transform infrared spectroscopy(FTIR),as well as physical,mechanical,andfire resistance characteristics of the laboratory-fabricated particleboards.Lignin and modified lignin resulted in improved thermal stability of the composites bonded with ULEF-UF while the improvement in the particleboard bonded with citric acid-sucrose was not significant.The introduction offiller exerted a higher influence on the UF-bonded particleboards compared to composites fabricated with citric acid-sucrose.Generally,the presence of lignin,lignosulfonate,and phosphorylated lignosulfonate enhanced the mechanical strength of the ULEF-bonded particleboards,although their dimensional stability has deteriorated.Markedly,the use of lignin and lignosulfonate enhanced thefire resis-tance of the particleboards produced with lower observed weight loss.All laboratory particleboards exhibited satisfactoryfire resistance,attaining a V-0 rating in according to the UL-94 standard.展开更多
Sugarcane bagasse is an agro-waste that could replace timber resources for the production of bio-composites.Composite boards such as particleboard offer an issue for the use and recycling of poor quality timber,and th...Sugarcane bagasse is an agro-waste that could replace timber resources for the production of bio-composites.Composite boards such as particleboard offer an issue for the use and recycling of poor quality timber,and these engineered products can overcome some solid wood limitations such as heterogeneity and dimension.Bagasse offers an alternative to wood chips for particleboard production but present some disadvantages as well,such as poor physico-mechanical properties.To address these issues,bagassefibers were treated with an innovative natural resin formulated with tannin and furfural.Impregnated particles with different concentrations of resin(5%,10%,and 15%m/m)were exposed to temperatures of 40℃,60℃,80℃,and 100℃ for resin curing.Various types of tannin-based adhesives,including tannin formaldehyde,tannin/formaldehyde-furfural,and tannin hex-amine,were utilized for bonding the treated bagasse particles.The resultant panels were assessed for their physical and mechanical properties and compared to those produced using Melamine-Urea-Formaldehyde(MUF)adhe-sive.The density of the panels varied from 650 to 730 kg/m^(3) depending on the resin concentration.The values for both modulus of elasticity and modulus of rupture increased as the resin concentration increased.The internal bonding values exhibited an increase with resin concentration up to a critical point,after which a decreasing trend was observed.The water absorption and thickness swelling were significantly reduced with an increase in resin concentration.However,the panels produced using MUF adhesive yielded the most favorable physico-mechanical properties.Additionally,the panels made with tannin-based adhesives met the minimum requirements specified in the standard EN 312(specifications for uncoated resin-bonded particleboards)for application in dry condi-tions.The analysis of formaldehyde emissions indicated that panels produced with tannin-based adhesives exhib-ited significantly lower emissions compared to those made with MUF.The tannin/furfural resin showed great potential for improving the quality of bagasse particleboard using tannin-based adhesives.展开更多
The demand for particleboard is increasing along with economic and population growth.However,two major barriers to the manufacture of particleboard are a shortage of raw materials(woodchips)and the emission of formald...The demand for particleboard is increasing along with economic and population growth.However,two major barriers to the manufacture of particleboard are a shortage of raw materials(woodchips)and the emission of formaldehyde from conventional adhesives.Agricultural by-products such as corn stalks contain an abundance of renewable lignocellulosic fiber.This study evaluates the effect of citric acid as a natural adhesive and fire retardant addition on the physical,mechanical,and fire retardancy properties of particleboards fabricated from corn stalks.A cost-effective and inorganic salt,calcium carbonate,was tested to enhance the fire retardancy.Ammonium dihydrogen phosphate was also considered as a comparative control.Particleboards with the addition of calcium carbonate was pretreated with sodium chloride.The particleboards were pressed for 10 min at 200℃.Japanese Industrial Standard JIS A 5908:2022 was used as the benchmark for the physical and mechanical tests.Fire retardancy was dynamically tested by simulating a Bushfire Attack Level of 19 kW/m^(2).The particleboard with 25 wt%citric acid had superior mechanical properties and complied with the JIS A 5908 standard for Type 13 base particleboard.Particleboard with the addition of calcium carbonate(5%and 10%)showed significantly delayed pyrolysis time.展开更多
Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particle...Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particles of fine(0.2 to 1.0 mm),medium(1.0 to 2.5 mm),and coarse(2.5 to 12.0 mm)sizes,derived from the bark of Leucaena leucocephala,were hot-pressed using a heating plate at 175℃for 7 min to create single-layer particleboards measuring 320 mm×320 mm×10 mm,targeting a density of 700 kg/m^(3).Subsequently,the samples were trimmed and conditioned at 20℃and 65%relative humidity.In this study,we compared bark particleboard bonded with urea formaldehyde(UF)adhesive to fine-sized particleboard bonded with demethylated lignin adhesive.The results indicated that bark particleboards utilizing demethylated lignin and UF adhesives exhibited similar qualities.Coarse particleboard showed differences in modulus of elasticity(MOE)and modulus of rupture(MOR),while medium-sized particles exhibited significant variations in moisture content(MC)and water absorption(WA).Furthermore,the thickness swelling of coarse and medium-sized particles under wet and oven-dried conditions exhibited notable distinctions.Overall,the demethylated lignin adhesive extracted from L.leucocephala bark demonstrated similar quality to UF adhesive,with particle size correlating inversely to the strength of the bark particleboard.展开更多
The building sector significantly influences the environment, notably through resource consumption and waste production. Evaluating locally available resources and adopting sustainable development practices are essent...The building sector significantly influences the environment, notably through resource consumption and waste production. Evaluating locally available resources and adopting sustainable development practices are essential to mitigate this impact. This study proposes the fabrication of a wood-polymer composite by recycling polystyrene and wood sawdust. Polystyrene was dissolved in a solvent to obtain a polymer matrix, which was then reinforced with recycled wood sawdust. The mixture was cold-pressed to form composite panels. Physical properties such as density and absorption, as well as mechanical properties like the modulus of elasticity and flexural strength, were examined. Results show that the physical and mechanical properties of the composites vary with the particle size distribution of the wood particles. The modulus of elasticity and flexural strength increase with particle size. The maximum values obtained for the modulus of elasticity and flexural strength are 842 MPa and 3.16 MPa, respectively. These physical and mechanical characteristics indicate that the developed composite material can be used to manufacture elements such as furniture, false ceilings, and lightweight partitions, thereby contributing to more sustainable construction practices.展开更多
Photon absorption parameters such as mass attenuation coefficients(μ_m),molar extinction coefficients(ε),total molecular(σ_(t,m)),atomic(σ_(t,a))and electronic(σ_(t,el))cross sections,half-value layers(X_(1/2)),t...Photon absorption parameters such as mass attenuation coefficients(μ_m),molar extinction coefficients(ε),total molecular(σ_(t,m)),atomic(σ_(t,a))and electronic(σ_(t,el))cross sections,half-value layers(X_(1/2)),tenth-value layers(X_(1/10)),mean free paths(λ),effective atomic numbers(Z_(eff)),and effective electron densities(N_(el))were estimated for defatted soy flour(DSF),soy protein concentrate(SPC),and soy protein isolate(SPI)-based Rhizophora spp.particleboard composites substituted with 10 wt%sodium hydroxide(NaOH)and 0,5,10,and 15 wt%itaconic acid polyamidoamine-epichlorohydrin(IA-PAE)adhesives.Elemental composition was assessed using ultrahigh-resolution field emission scanning electron microscopy-energy dispersive X-ray spectrometry(UHR-FESEM-EDX).The interaction parameters were evaluated for K_(α1)photons at16.59,17.46,21.21,and 25.26 keV,employing a low-energy germanium(LEGe)detector system and an~(241)Amγ-ray source.X-ray diffraction characterization revealed an amorphous phase in the developed particleboard composites.Samples DSF15',SPC15',and SPI15'exhibited the highest values ofμ_m,ε,σ_(t,m),Zeff,and N_(el)among all of the studied particleboard samples,within the range of measured photon energies.In addition,all of the modified samples exhibited lower X_(1/2),X_(1/10),λ,σ_(t,a),andσ_(t,el)than the unmodified samples,with DSF-,SPC-,and SPI/NaOH/Rhizophora spp./IA-PAE(15 wt%),indicating insignificant changes.The current results of the particleboard samples'analysis can be useful for medical radiation applications and shielding research.展开更多
We investigated the hydration behavior and some physical/mechanical properties of cement-bonded particleboard （CBPB） containing particles of wheat straw and poplar wood at various usage ratios and bonded with Portla...We investigated the hydration behavior and some physical/mechanical properties of cement-bonded particleboard （CBPB） containing particles of wheat straw and poplar wood at various usage ratios and bonded with Portland cement mixed with different levels of inorganic additives. We determined the setting time and compression strength of cement pastes containing different additives and particles, and studied the effects of these additives and particles on thickness swelling, internal bond strength and modulus of rupture of CBPB by using RSM （Response Surface Methodology）. The mathematical model equations （second-order response functions） were derived to optimize properties of CBPB by computer simulation programming. Predicted values were in agreement with experimental values （R2 values of 0.93, 0.96 and 0.96 for TS, IB and MOR, respectively）. RSM can be efficiently applied to model panel properties. The variables can affect the properties of panels. The cement composites with bending strength 〉 12.5 MPa and internal bond strength 〉 0.28 MPa can be made by using wheat straw as a reinforcing material. Straw particle usage up to 11.5% in the mixture satisfies the minimum requirements of International Standard, EN 312 （2003） for IB and MOR. The dose of 4.95% calcium chloride, by weight of cement, can improve mechanical properties of the panels at the minimum requirement of EN 312. By increasing straw content from 0 to 30%, TS was reduced by increasing straw particle usage up to 1.5% and with 5.54% calcium chloride in the mixture, TS satisfied the EN 312 standard.展开更多
We compared resistance to decay, mold fungi, termites and insect larvae of particleboards incorporated with the raw boron minerals ulexite and colemanite to that of particleboards impregnated with the commercial boron...We compared resistance to decay, mold fungi, termites and insect larvae of particleboards incorporated with the raw boron minerals ulexite and colemanite to that of particleboards impregnated with the commercial boron preservative zinc borate, or boric acid plus a borax mixture. We also quantified water absorption, thickness swell and boron release of particleboards. Ulexite had the best decay resistance, and colemanite had the best termite resistance. However, ulexite and colemanite were not as effective as zinc borate or the boric acid/borax mixture in preventing mold growth. In general, the boric acid/borax mixture combination was more effective against Anobium larvae than the other treatments. Less boron was released by specimens containing zinc borate and colemanite than by those containing ulexite or the boric acid/borax mixture. In general, water absorption and thickness swell were similar among the different treatments, but both were slightly higher in the ulexite-incorporated specimens. Further mechanical tests will be needed to evaluate the particle- board properties and thereby the compatibility of these boron minerals with various manufacturing processes.展开更多
Urea-formaldehyde （UF） adhesive is the main source of formaldehyde emission from UF-bonded boards. The components in waste tea leaves can react with formaldehyde to serve as a raw material in the production of low f...Urea-formaldehyde （UF） adhesive is the main source of formaldehyde emission from UF-bonded boards. The components in waste tea leaves can react with formaldehyde to serve as a raw material in the production of low formaldehyde emission boards. In our study, waste tea leaves and UF adhesive were employed in the preparation of waste tea leaves particleboard （WTLB）. An orthogonal experimental method was applied to investigate the effects of process parameters on formaldehyde emission and mechanical properties of WTLB. The results indicated that： 1） waste tea leaves had the ability to abate formaldehyde emission from boards; and 2） density of the WTLB was a significant factor affecting its modulus of rupture （MOR）, modulus of elasticity （MOE） and internal bonding （IB）.展开更多
We evaluated the potential use of amino silane coupling agent （SiNH） to improve physical and mechanical properties of UF-bonded wheat straw （Triticurn aestivum L.） poplar wood particleboard. We examined the effect...We evaluated the potential use of amino silane coupling agent （SiNH） to improve physical and mechanical properties of UF-bonded wheat straw （Triticurn aestivum L.） poplar wood particleboard. We examined the effects of varied content of silane coupling agent content and ratios of straw to poplar wood particles on particleboard prop- erties. The ratios of straw to poplar wood particles were 100：0, 85：15, 70：30 and 55：45. Silane coupling agent content was tested at three levels, 0, 5 and 10 %. The experimental panels were tested for their mechanical strength, including modulus of elasticity （MOE）, modulus of rupture （MOR）, intemal bonding （IB） and physical properties according to procedures specified in DIN 68763 （Chipboard for special purposes in building construction： concepts, requirements, testing, 1982-03, 1982）. All board properties were improved by the addition of silane cou- pling agent. The use of poplar wood particles had a positive effect on the mechanical properties of wheat straw parti- cleboard but had a negative effect on physical properties （thickness swelling and water absorption）.展开更多
Gypsum-bonded particleboard(GBPB) panels were made from various mixtures of particles of bagasse(Saccharum officinarum L.) and wheat straw(Triticum aestivum L.), bonded with different ratios of particle/gypsum. This s...Gypsum-bonded particleboard(GBPB) panels were made from various mixtures of particles of bagasse(Saccharum officinarum L.) and wheat straw(Triticum aestivum L.), bonded with different ratios of particle/gypsum. This study examined the feasibility of bagasse and wheat straw particles in the production of GBPB. One-layer experimental GBPBs with a density of 1.05 or 1.20 g·cm 3were manufactured at different ratios of bagasse/wheat straw, i.e., 100%/0%, 93.75%/6.25%, 87.5%/12.5%, 75%/25%, 50%/50%, 25%/75% and 0%/100% using two particle/ gypsum composite ratios, i.e., 1/2.75 and 1/3.25 by weight. Thickness swelling(TS), water absorption(WA), modulus of rupture(MOR), modulus of elasticity(MOE) and internal bond strength(IB) properties of the boards were evaluated and a statistical analysis was performed in order to examine the possible feasibility of these agricultural residues for use in commercial GBPB manufacturing. We determined that WA of panels decreases as the amount of straw increases to 100% and the LR/G(wood/gypsum) ratio decreases to 1/3.25, whereas the TS of panels decreases as the proportion of straw decreases to 0% and the LR/G ratio increases to 1/2.75. The experimental results also show that the MOR and MOE of panels containing 0%, 6.25% and 12.5% wheat straw with a LR/G ratio of 1/2.75 were higher than those of panels made from 25%–100% wheat straw with a LR/G ratio of 1/2.75, as well as those from all other percentages of straw with a LR/G ratio of 1/3.25. On the other hand, the IB of panels containing more than 12.5% straw with LR/G ratios of 1/2.75 and 1/3.25 were lower than those of panels made from 0–12.5% straw also with both LR/G ratios. Panels consisting of 0%, 6.25% and 12.5% wheat straw with LR/G ratios of 1/2.75 and 1/3.25 met the minimum EN standard requirements of mechanical properties for general purposes. All of the panels containing 0–100% wheat straw with a LR/ G ratio of 1/2.75 or 1/3.25 met the required level of TS for 24-h immersion.展开更多
The microstructures of gypsum board and gypsum particleboard were observed by SEM. The effects of retarder and waterproof agent on the shape and the average dimension of the gypsum crystal were discussed. The mechanis...The microstructures of gypsum board and gypsum particleboard were observed by SEM. The effects of retarder and waterproof agent on the shape and the average dimension of the gypsum crystal were discussed. The mechanism was investigated as well. Four typical instances, i e, the gypsum crystal shape, the gypsum combined with particles on the particles surface, the gypsum combined with particles on the wood cross section and the gypsum combined with particles inside the wood cell cavity were selected and observed. Furthermore, the agglomeration and cementation mechanism between gypsum and particle were studied.展开更多
Emission of volatile organic compounds (VOCs) during drying of wood particles for particleboard manufacture, or for production of refined biofuels, is a potential environmental problem. The aim of this work is to stud...Emission of volatile organic compounds (VOCs) during drying of wood particles for particleboard manufacture, or for production of refined biofuels, is a potential environmental problem. The aim of this work is to study the emissions of VOCs during drying, and the influence on the emissions by different drying parameters.The experiments have mainly been done in a batch fluidized bed dryer, but measurements have also been done in a, pilot scale, continuous fluidized bed dryer. The parameters studied are air flow rate through the bed, air temperature, air dewpoint, and bed height. Since the present trend in biofuels and particle drying is towards very high dewpoints during drying, some measurements have been made at dewpoints up to 95℃, corresponding to a water content of 3.2 kg water per kilogram dry air. The emissions have been measured in two different ways,online during drying with a flame ionization detector and through wood analyses of the terpene content in the wood particles before and after drying. Substantial work has been made in developing the latter method as well as developing the drying equipment to be able to produce a wide range of conditions of the drying medium. It was shown that the VOCs emitted, during wood particle drying, mainly consist of terpenes. The behavior of the emissions was typical, at first contact with the drying gas a sharp peak in the release rate was detected. After that,the release rate stabilizes and declines slowly to a point where the material temperature increases and results in a second small peak in the release rate. Typically 80%-90% of the initial terpene content in the material was emitted during drying to low moisture content and it is not possible to significantly influence this release by changing the drying conditions. Up to 50% of the emitted terpenes are released during a very short period after contact with the drying medium. This fact could be utilized by employing a 2-step drying process. The fact that the VOC concentration in the inert gas gets much higher when drying at higher dewpoints could be taken into consideration when dealing with closed loop applications where the inert gas after the dryer is burnt.展开更多
A three reagents adhesive system for wood particleboards not containing any aldehyde was developed by the reaction of glucose or sucrose with triacetin(glycerin triacetate)and with hexamethylene diamine.The system was...A three reagents adhesive system for wood particleboards not containing any aldehyde was developed by the reaction of glucose or sucrose with triacetin(glycerin triacetate)and with hexamethylene diamine.The system was found to be based on the mix of three reactions,namely the reaction of(i)glucose with triacetin,(ii)of the diamine with triacetin,and(iii)of glucose with the diamine.The chemical species formed were identified by Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-ToF)mass spectrometry.Wood particleboard panels were prepared with this adhesive system and gave good internal bond(IB)strength results suitable for interior grade panels and with extremely low formaldehyde emission.展开更多
文摘Cement-bonded particleboards of 6 mm in thickness were manufactured using maize stalk （Zea mays） particles of uniform sizes at three levels of board density and additive concentrations respectively. The bending strength and dimensional properties were assessed. Increase in board density and additive concentration caused increase in Modulus of rupture （MOR）, Modulus of elasticity （MOE）, and decrease in Thickness swelling （TS） and Water absorption （WA）. The MOR, MOE and TS of the boards were significantly affected by board density except for WA, but additive concentration affected all the boards＇ properties examined at p ≥ 0.05. Strong and dimensional stable cement-bonded boards could be manufactured from maize stalk particles with Portland cement as the binder after hot water treatment. Although the dimensional stability and mechanical strength properties of the boards were affected by the board density and additive concentration, the study revealed that cement-bonded particleboards could be manufactured from maize stalk （Zea mays） particles. However, the increase in board density and additive concentration could cause the increase in MOR and MOE, and cause the decrease in TS and WA of boards.
文摘Lignocellulosic residues resulting from agricultural activities and urban centers cause pollution. A possible solution to this problem is to combine these residues with woody plants to produce particleboards. The purpose of this study was to evaluate decay resistance, coating and burning properties and the change of color caused by accelerated weathering of particleboards manufactured with a combination of 3 woody species used for commercial reforestation in tropical areas (Cupressus lusitanica, Gmelina arborea and Tectona grandis), pineapple (Ananas comosus) leaves from the crown and the plant (PL), empty fruit bunch of Elaeis guineensis (EBF) and tetra pak packages (TP). According to the results, the mixtures of T. grandis and EFB were classified as moderately resistant and other mixtures (woody species and PL or TP) were classified as slightly resistant. The finish performance test determined that the mixtures with TP presented the best performance, followed by the mixtures with oil palm components and the mixtures composed of pineapple leaves. Regarding lacquer consumption, no differences were found between the mixtures. The combustion test determined that particleboards with TP and EFB showed the highest resistance to combustion, while pineapple presented the lowest resistances to combustion. In the accelerated weathering exposure test, the mixtures of the three species with TP showed the best performance in accelerated weathering. Contrariwise, the mixtures with pineapple leaves showed the lowest resistance to accelerated weathering. Oil palm particleboards presented lower resistance to weathering than TP, though higher than pineapple leaves’ resistance.
基金The authors thank Zhejiang Provincial Science and Technology Department Project(2019F1065-4)&Zhejiang Provincial Natural Science Foundation(LY19C160004)&Public Welfare Technology Research Agricultural Project of Zhejiang Province(2013C32104)for their financial contributions.
文摘Using 1–8 years bamboo as materials,the content of different chemical constituent was tested,and the reactive oxygen species(ROS)free radicals produced from laccase treated bamboo were detected by electron spin-resonance(ESR)spectroscope.The wet-process particleboard was made from laccase-treated bamboo by hot pressing and board mechanical properties including internal bond strength(IB),modulus of rupture(MOR)and thickness swelling(TS)after 2-hours water absorption were tested under different conditions.Results showed that laccase mainly catalyze the bamboo components and improved the bonding strength of laccase-treated boards.By ESR measurement on each single component such as milled bamboo lignin,xylan and pore cotton treated with laccase,it was proved that laccase helped the degradation of bamboo lignin to produce ROS free radicals and could not catalyze the oxidation of cellulose and hemicelluloses.A logarithmic function relationship was found between board mechanical properties and ROS free radical level.It is optimal to using 5-year-old bamboo for high efficient utilization.The laccase treatment improves the activity of bamboo particles participating in self-adhesion reaction.
文摘Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue for particleboard production. This study assessed the decay resistance of particleboards produced from four agro-forest residues using cassava starch and urea formaldehyde as adhesives. <i><span>Musa paradisiaca pseudostem</span></i><span>, </span><i><span>Theobroma cacao </span></i><span>stem and pod, and sawdust of </span><i><span>Ceiba pentandra</span></i><span> were used for the study. Properties determined were: Weight loss, decay resistance rating and decay susceptibility index. These properties were evaluated after 12 weeks of exposure to </span><i><span>Coriolopsis polyzona</span></i><span> in accordance with ASTM D 2017</span><span>-</span><span>05. The results indicate that the weight loss for </span><i><span>Musa paradisiaca pseudostem</span></i><span> particleboard was least for both urea formaldehyde and cassava starch adhesives. Even though almost all the particleboards produced were classified as resistant or highly resistant to fungi attack, those produced with urea formaldehyde had better decay resistance properties than that of cassava starch. Furthermore, particleboards coated with synthetic polyvinyl lacquer had better resistance to fungi attack than the uncoated ones. At 5% level of significance, the agro-forest residue, adhesive and surface finish as well as their interactions had significant effects on decay resistance of the particleboards produced. It is recommended that further studies which aim at determining the effect of combination of the agro-forest residues and that of urea formaldehyde and cassava starch be conducted to determine their effects on decay properties of particleboards.</span>
文摘This work contributes to the use of alternative adhesives in the wood-based industry,where pine wood is commonly used.The investigation identifies the influence and the optimal content(8,12 and 15wt%)of a bio-based polyurethane adhesive in the production of medium density particleboards(MDP).A compaction pressure of 4 MPa at 100oC for 10 minutes is considered in the manufacture of panels based on pine wood residues and bio-based resin.The bulk density,flexural modulus(MOE)and strength(MOR)properties under static three-point bending are obtained according to the Brazilian standard NBR 14810.The results are compared with NBR 14810 and other standards to verify its performance based on the minimum requirements.Bulk density is not significantly affected by the investigated adhesive levels.MOE and MOR reach average values equivalent to 12wt%and 15wt%of the adhesive,and both meet the minimum requirements established in international normative documents.The adhesive level range responsible for maximizingρ,MOE and MOR is between 12.42wt%and 15.79wt%.
文摘The utilization of oil palm biomass in the production of high-value products has increased substantially.Due to the presence of sugars and starches in their tissues,oil palms have an exceptionally low natural resistance to fungi,making them susceptible to contamination.In this study,the properties of particleboard made from oil palmfibers,namely empty fruit bunches(EFB),oil palm trunks(OPT),and oil palm fronds(OPF)fibers and its poten-tial for fungal attack were evaluated.The chemical composition,spectroscopic characterization,morphological features,and elemental analysis of oil palm biomassfibers were identified and thoroughly examined.The mechan-ical properties and dimensional stability of the boards were assessed based on Japanese Industrial Standards(JIS)and American National Standards Institute(ANSI)guidelines.The density,strength,and moisture resistance of particleboard made from OPTfibers may vary from those made from OPF and EFB due to inherent changes in chemical composition andfiber structure.These differences have an impact on the overall performance of the particleboard.Based on the ANOVA and Tukey’s test results,significant differences in elasticity properties were observed mainly between OPT and otherfibers,while bending strength revealed notable differences between various pairs of particleboards.The evaluation also highlighted variations in dimensional stability and water absorption capabilities.However,bending strength properties did not demonstrate any significant deviations.For the fungi test,fungal activity on the boards was observed over a two-week period in a controlled environment.The study revealed that oil palm-based particleboard exhibited susceptibility to fungal attacks,particularly from Aspergillus sp.,Trichoderma sp.,and Paecilomyces variotii.Thesefindings highlight the necessity for additional treatments to control or prevent fungal growth,thereby enhancing the commercial value of the particleboards.
基金funded by the Equity Project Universitas Sumatera Utara(Number:10/UN5.2.3.1/PPM/KPEP/2023),which is entitled Pengembangan Papan Partikel Tahan Api Rendah Emisi Berbahan Limbah Tanaman Mangrove dan Limbah Tanaman Pertanian Melalui Penambahan Lignin Terfosforilasi Sebagai Filler.PT Greenei Alam Indonesia(PT GAI)contributed to providing the areca leaf sheath through the implementation of a collaboration agreement with the Research Center for Biomass and Bioproducts BRIN FY 2023-2025.
文摘Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics of particleboards were compared to that of ultralow emitting formaldehyde(ULEF-UF).Thefillers derived from Eucalyptus spp.kraft-lignin were added forflame retardancy enhancement.10%of each lignin and modified lig-nin was added into the ULEF-UF and citric acid-sucrose bonded particleboards.Analyses applied to particle-boards included thermal characteristics,X-ray diffraction analysis(XRD),morphological properties,Fourier transform infrared spectroscopy(FTIR),as well as physical,mechanical,andfire resistance characteristics of the laboratory-fabricated particleboards.Lignin and modified lignin resulted in improved thermal stability of the composites bonded with ULEF-UF while the improvement in the particleboard bonded with citric acid-sucrose was not significant.The introduction offiller exerted a higher influence on the UF-bonded particleboards compared to composites fabricated with citric acid-sucrose.Generally,the presence of lignin,lignosulfonate,and phosphorylated lignosulfonate enhanced the mechanical strength of the ULEF-bonded particleboards,although their dimensional stability has deteriorated.Markedly,the use of lignin and lignosulfonate enhanced thefire resis-tance of the particleboards produced with lower observed weight loss.All laboratory particleboards exhibited satisfactoryfire resistance,attaining a V-0 rating in according to the UL-94 standard.
基金This work was supported by the office of vice-president for research and technology,University of Tehran,Gundishapur project 1584/45227SG,and Campus France.
文摘Sugarcane bagasse is an agro-waste that could replace timber resources for the production of bio-composites.Composite boards such as particleboard offer an issue for the use and recycling of poor quality timber,and these engineered products can overcome some solid wood limitations such as heterogeneity and dimension.Bagasse offers an alternative to wood chips for particleboard production but present some disadvantages as well,such as poor physico-mechanical properties.To address these issues,bagassefibers were treated with an innovative natural resin formulated with tannin and furfural.Impregnated particles with different concentrations of resin(5%,10%,and 15%m/m)were exposed to temperatures of 40℃,60℃,80℃,and 100℃ for resin curing.Various types of tannin-based adhesives,including tannin formaldehyde,tannin/formaldehyde-furfural,and tannin hex-amine,were utilized for bonding the treated bagasse particles.The resultant panels were assessed for their physical and mechanical properties and compared to those produced using Melamine-Urea-Formaldehyde(MUF)adhe-sive.The density of the panels varied from 650 to 730 kg/m^(3) depending on the resin concentration.The values for both modulus of elasticity and modulus of rupture increased as the resin concentration increased.The internal bonding values exhibited an increase with resin concentration up to a critical point,after which a decreasing trend was observed.The water absorption and thickness swelling were significantly reduced with an increase in resin concentration.However,the panels produced using MUF adhesive yielded the most favorable physico-mechanical properties.Additionally,the panels made with tannin-based adhesives met the minimum requirements specified in the standard EN 312(specifications for uncoated resin-bonded particleboards)for application in dry condi-tions.The analysis of formaldehyde emissions indicated that panels produced with tannin-based adhesives exhib-ited significantly lower emissions compared to those made with MUF.The tannin/furfural resin showed great potential for improving the quality of bagasse particleboard using tannin-based adhesives.
文摘The demand for particleboard is increasing along with economic and population growth.However,two major barriers to the manufacture of particleboard are a shortage of raw materials(woodchips)and the emission of formaldehyde from conventional adhesives.Agricultural by-products such as corn stalks contain an abundance of renewable lignocellulosic fiber.This study evaluates the effect of citric acid as a natural adhesive and fire retardant addition on the physical,mechanical,and fire retardancy properties of particleboards fabricated from corn stalks.A cost-effective and inorganic salt,calcium carbonate,was tested to enhance the fire retardancy.Ammonium dihydrogen phosphate was also considered as a comparative control.Particleboards with the addition of calcium carbonate was pretreated with sodium chloride.The particleboards were pressed for 10 min at 200℃.Japanese Industrial Standard JIS A 5908:2022 was used as the benchmark for the physical and mechanical tests.Fire retardancy was dynamically tested by simulating a Bushfire Attack Level of 19 kW/m^(2).The particleboard with 25 wt%citric acid had superior mechanical properties and complied with the JIS A 5908 standard for Type 13 base particleboard.Particleboard with the addition of calcium carbonate(5%and 10%)showed significantly delayed pyrolysis time.
基金the financial support provided by UMS Great(GUG0217-1/2018),which played a crucial role in the completion of this study.
文摘Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particles of fine(0.2 to 1.0 mm),medium(1.0 to 2.5 mm),and coarse(2.5 to 12.0 mm)sizes,derived from the bark of Leucaena leucocephala,were hot-pressed using a heating plate at 175℃for 7 min to create single-layer particleboards measuring 320 mm×320 mm×10 mm,targeting a density of 700 kg/m^(3).Subsequently,the samples were trimmed and conditioned at 20℃and 65%relative humidity.In this study,we compared bark particleboard bonded with urea formaldehyde(UF)adhesive to fine-sized particleboard bonded with demethylated lignin adhesive.The results indicated that bark particleboards utilizing demethylated lignin and UF adhesives exhibited similar qualities.Coarse particleboard showed differences in modulus of elasticity(MOE)and modulus of rupture(MOR),while medium-sized particles exhibited significant variations in moisture content(MC)and water absorption(WA).Furthermore,the thickness swelling of coarse and medium-sized particles under wet and oven-dried conditions exhibited notable distinctions.Overall,the demethylated lignin adhesive extracted from L.leucocephala bark demonstrated similar quality to UF adhesive,with particle size correlating inversely to the strength of the bark particleboard.
文摘The building sector significantly influences the environment, notably through resource consumption and waste production. Evaluating locally available resources and adopting sustainable development practices are essential to mitigate this impact. This study proposes the fabrication of a wood-polymer composite by recycling polystyrene and wood sawdust. Polystyrene was dissolved in a solvent to obtain a polymer matrix, which was then reinforced with recycled wood sawdust. The mixture was cold-pressed to form composite panels. Physical properties such as density and absorption, as well as mechanical properties like the modulus of elasticity and flexural strength, were examined. Results show that the physical and mechanical properties of the composites vary with the particle size distribution of the wood particles. The modulus of elasticity and flexural strength increase with particle size. The maximum values obtained for the modulus of elasticity and flexural strength are 842 MPa and 3.16 MPa, respectively. These physical and mechanical characteristics indicate that the developed composite material can be used to manufacture elements such as furniture, false ceilings, and lightweight partitions, thereby contributing to more sustainable construction practices.
基金supported by the Universiti Sains Malaysia(USM)the Research University Grant allocation(Nos.304/PFIZIK/6316173,1001/PFIZIK/822173,203/PTEKIND/6711525)。
文摘Photon absorption parameters such as mass attenuation coefficients(μ_m),molar extinction coefficients(ε),total molecular(σ_(t,m)),atomic(σ_(t,a))and electronic(σ_(t,el))cross sections,half-value layers(X_(1/2)),tenth-value layers(X_(1/10)),mean free paths(λ),effective atomic numbers(Z_(eff)),and effective electron densities(N_(el))were estimated for defatted soy flour(DSF),soy protein concentrate(SPC),and soy protein isolate(SPI)-based Rhizophora spp.particleboard composites substituted with 10 wt%sodium hydroxide(NaOH)and 0,5,10,and 15 wt%itaconic acid polyamidoamine-epichlorohydrin(IA-PAE)adhesives.Elemental composition was assessed using ultrahigh-resolution field emission scanning electron microscopy-energy dispersive X-ray spectrometry(UHR-FESEM-EDX).The interaction parameters were evaluated for K_(α1)photons at16.59,17.46,21.21,and 25.26 keV,employing a low-energy germanium(LEGe)detector system and an~(241)Amγ-ray source.X-ray diffraction characterization revealed an amorphous phase in the developed particleboard composites.Samples DSF15',SPC15',and SPI15'exhibited the highest values ofμ_m,ε,σ_(t,m),Zeff,and N_(el)among all of the studied particleboard samples,within the range of measured photon energies.In addition,all of the modified samples exhibited lower X_(1/2),X_(1/10),λ,σ_(t,a),andσ_(t,el)than the unmodified samples,with DSF-,SPC-,and SPI/NaOH/Rhizophora spp./IA-PAE(15 wt%),indicating insignificant changes.The current results of the particleboard samples'analysis can be useful for medical radiation applications and shielding research.
基金supported by Department of Wood and Paper Science and Technology,University of Zabol
文摘We investigated the hydration behavior and some physical/mechanical properties of cement-bonded particleboard （CBPB） containing particles of wheat straw and poplar wood at various usage ratios and bonded with Portland cement mixed with different levels of inorganic additives. We determined the setting time and compression strength of cement pastes containing different additives and particles, and studied the effects of these additives and particles on thickness swelling, internal bond strength and modulus of rupture of CBPB by using RSM （Response Surface Methodology）. The mathematical model equations （second-order response functions） were derived to optimize properties of CBPB by computer simulation programming. Predicted values were in agreement with experimental values （R2 values of 0.93, 0.96 and 0.96 for TS, IB and MOR, respectively）. RSM can be efficiently applied to model panel properties. The variables can affect the properties of panels. The cement composites with bending strength 〉 12.5 MPa and internal bond strength 〉 0.28 MPa can be made by using wheat straw as a reinforcing material. Straw particle usage up to 11.5% in the mixture satisfies the minimum requirements of International Standard, EN 312 （2003） for IB and MOR. The dose of 4.95% calcium chloride, by weight of cement, can improve mechanical properties of the panels at the minimum requirement of EN 312. By increasing straw content from 0 to 30%, TS was reduced by increasing straw particle usage up to 1.5% and with 5.54% calcium chloride in the mixture, TS satisfied the EN 312 standard.
基金financially supported by the Coordination Unit for Scientific Research of Istanbul University,Turkey(Project Nos:32421 and BEK 20218)
文摘We compared resistance to decay, mold fungi, termites and insect larvae of particleboards incorporated with the raw boron minerals ulexite and colemanite to that of particleboards impregnated with the commercial boron preservative zinc borate, or boric acid plus a borax mixture. We also quantified water absorption, thickness swell and boron release of particleboards. Ulexite had the best decay resistance, and colemanite had the best termite resistance. However, ulexite and colemanite were not as effective as zinc borate or the boric acid/borax mixture in preventing mold growth. In general, the boric acid/borax mixture combination was more effective against Anobium larvae than the other treatments. Less boron was released by specimens containing zinc borate and colemanite than by those containing ulexite or the boric acid/borax mixture. In general, water absorption and thickness swell were similar among the different treatments, but both were slightly higher in the ulexite-incorporated specimens. Further mechanical tests will be needed to evaluate the particle- board properties and thereby the compatibility of these boron minerals with various manufacturing processes.
文摘Urea-formaldehyde （UF） adhesive is the main source of formaldehyde emission from UF-bonded boards. The components in waste tea leaves can react with formaldehyde to serve as a raw material in the production of low formaldehyde emission boards. In our study, waste tea leaves and UF adhesive were employed in the preparation of waste tea leaves particleboard （WTLB）. An orthogonal experimental method was applied to investigate the effects of process parameters on formaldehyde emission and mechanical properties of WTLB. The results indicated that： 1） waste tea leaves had the ability to abate formaldehyde emission from boards; and 2） density of the WTLB was a significant factor affecting its modulus of rupture （MOR）, modulus of elasticity （MOE） and internal bonding （IB）.
文摘We evaluated the potential use of amino silane coupling agent （SiNH） to improve physical and mechanical properties of UF-bonded wheat straw （Triticurn aestivum L.） poplar wood particleboard. We examined the effects of varied content of silane coupling agent content and ratios of straw to poplar wood particles on particleboard prop- erties. The ratios of straw to poplar wood particles were 100：0, 85：15, 70：30 and 55：45. Silane coupling agent content was tested at three levels, 0, 5 and 10 %. The experimental panels were tested for their mechanical strength, including modulus of elasticity （MOE）, modulus of rupture （MOR）, intemal bonding （IB） and physical properties according to procedures specified in DIN 68763 （Chipboard for special purposes in building construction： concepts, requirements, testing, 1982-03, 1982）. All board properties were improved by the addition of silane cou- pling agent. The use of poplar wood particles had a positive effect on the mechanical properties of wheat straw parti- cleboard but had a negative effect on physical properties （thickness swelling and water absorption）.
文摘Gypsum-bonded particleboard(GBPB) panels were made from various mixtures of particles of bagasse(Saccharum officinarum L.) and wheat straw(Triticum aestivum L.), bonded with different ratios of particle/gypsum. This study examined the feasibility of bagasse and wheat straw particles in the production of GBPB. One-layer experimental GBPBs with a density of 1.05 or 1.20 g·cm 3were manufactured at different ratios of bagasse/wheat straw, i.e., 100%/0%, 93.75%/6.25%, 87.5%/12.5%, 75%/25%, 50%/50%, 25%/75% and 0%/100% using two particle/ gypsum composite ratios, i.e., 1/2.75 and 1/3.25 by weight. Thickness swelling(TS), water absorption(WA), modulus of rupture(MOR), modulus of elasticity(MOE) and internal bond strength(IB) properties of the boards were evaluated and a statistical analysis was performed in order to examine the possible feasibility of these agricultural residues for use in commercial GBPB manufacturing. We determined that WA of panels decreases as the amount of straw increases to 100% and the LR/G(wood/gypsum) ratio decreases to 1/3.25, whereas the TS of panels decreases as the proportion of straw decreases to 0% and the LR/G ratio increases to 1/2.75. The experimental results also show that the MOR and MOE of panels containing 0%, 6.25% and 12.5% wheat straw with a LR/G ratio of 1/2.75 were higher than those of panels made from 25%–100% wheat straw with a LR/G ratio of 1/2.75, as well as those from all other percentages of straw with a LR/G ratio of 1/3.25. On the other hand, the IB of panels containing more than 12.5% straw with LR/G ratios of 1/2.75 and 1/3.25 were lower than those of panels made from 0–12.5% straw also with both LR/G ratios. Panels consisting of 0%, 6.25% and 12.5% wheat straw with LR/G ratios of 1/2.75 and 1/3.25 met the minimum EN standard requirements of mechanical properties for general purposes. All of the panels containing 0–100% wheat straw with a LR/ G ratio of 1/2.75 or 1/3.25 met the required level of TS for 24-h immersion.
基金Funded by the National Natural Science Foundation of China (No. 30371130) the NSFU and KOSEF cooperation research in 2004
文摘The microstructures of gypsum board and gypsum particleboard were observed by SEM. The effects of retarder and waterproof agent on the shape and the average dimension of the gypsum crystal were discussed. The mechanism was investigated as well. Four typical instances, i e, the gypsum crystal shape, the gypsum combined with particles on the particles surface, the gypsum combined with particles on the wood cross section and the gypsum combined with particles inside the wood cell cavity were selected and observed. Furthermore, the agglomeration and cementation mechanism between gypsum and particle were studied.
文摘Emission of volatile organic compounds (VOCs) during drying of wood particles for particleboard manufacture, or for production of refined biofuels, is a potential environmental problem. The aim of this work is to study the emissions of VOCs during drying, and the influence on the emissions by different drying parameters.The experiments have mainly been done in a batch fluidized bed dryer, but measurements have also been done in a, pilot scale, continuous fluidized bed dryer. The parameters studied are air flow rate through the bed, air temperature, air dewpoint, and bed height. Since the present trend in biofuels and particle drying is towards very high dewpoints during drying, some measurements have been made at dewpoints up to 95℃, corresponding to a water content of 3.2 kg water per kilogram dry air. The emissions have been measured in two different ways,online during drying with a flame ionization detector and through wood analyses of the terpene content in the wood particles before and after drying. Substantial work has been made in developing the latter method as well as developing the drying equipment to be able to produce a wide range of conditions of the drying medium. It was shown that the VOCs emitted, during wood particle drying, mainly consist of terpenes. The behavior of the emissions was typical, at first contact with the drying gas a sharp peak in the release rate was detected. After that,the release rate stabilizes and declines slowly to a point where the material temperature increases and results in a second small peak in the release rate. Typically 80%-90% of the initial terpene content in the material was emitted during drying to low moisture content and it is not possible to significantly influence this release by changing the drying conditions. Up to 50% of the emitted terpenes are released during a very short period after contact with the drying medium. This fact could be utilized by employing a 2-step drying process. The fact that the VOC concentration in the inert gas gets much higher when drying at higher dewpoints could be taken into consideration when dealing with closed loop applications where the inert gas after the dryer is burnt.
文摘A three reagents adhesive system for wood particleboards not containing any aldehyde was developed by the reaction of glucose or sucrose with triacetin(glycerin triacetate)and with hexamethylene diamine.The system was found to be based on the mix of three reactions,namely the reaction of(i)glucose with triacetin,(ii)of the diamine with triacetin,and(iii)of glucose with the diamine.The chemical species formed were identified by Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-ToF)mass spectrometry.Wood particleboard panels were prepared with this adhesive system and gave good internal bond(IB)strength results suitable for interior grade panels and with extremely low formaldehyde emission.
