Durability characteristics of cement-bonded particleboards manufactured from maize stalk residue

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.

Fungal Decay, Coating, Burning Properties and Change of Color of Particleboards Manufactured with Woody Biomass, Agricultural Wastes and Tetra Pak Residues

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.

Bonding Mechanism of Bamboo Particleboards Made by Laccase Treatment

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.

Decay Resistance of Particleboards Manufactured with Four Agro-Forest Residues Using Cassava Starch and Urea Formaldehyde as Adhesives

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. Musa paradisiaca pseudostem, Theobroma cacao stem and pod, and sawdust of Ceiba pentandra 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 Coriolopsis polyzona in accordance with ASTM D 2017-05. The results indicate that the weight loss for Musa paradisiaca pseudostem 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.

Determination of the Adhesive Content of Medium Density Particleboards Produced with Bio-based Polymer

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%.

Properties of Bark Particleboard Bonded with Demethylated Lignin Adhesives Derived from Leucaena leucocephala Bark

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.

Thermo-Mechanical, Physico-Chemical, Morphological, and Fire Characteristics of Eco-Friendly Particleboard Manufactured with Phosphorylated Lignin Addition

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.

MALDI ToF Investigation of the Reaction of Soy Protein Isolate with Glutaraldehyde for Wood Adhesives

Soy protein adhesives are currently a hot research topic in the wood panels industry for the abundant raw material reserves,reasonable price and outstanding environmental features.But their poor water resistance,low bonding strength and intolerance to mold are major drawbacks,so that proper modification before use is essential.Glutaraldehyde is one of the more apt cross-linking agents for soybean protein adhesives,which can effectively improve the bonding strength and water resistance of the adhesive.Equally,glutaraldehyde is also an efficient and broad-spectrum fungicide that can significantly improve the anti-fungal properties of a soy protein adhesive.In the work presented here,matrix assisted laser desorption ionization(MALDI-ToF)mass spectrometry and Fourier transform infrared spectroscopy techniques were used to analyze the reaction mechanism of glutaraldehyde cross-linking soybean protein.The results confirmed the reaction of the aldehyde group with amino groups of the side chains and the amide groups of the peptide linkages constituting the skeletal chain of the protein.The laboratory plywood and particleboard bonded with glutaraldehyde-soy bean protein adhesives were prepared to determine the adhesive bonding properties,the dry strength,24 h cold water soaking wet strength and 3 h hot water(63°C)wet strength of plywood were 2.03,1.13 and 0.75 MPa,respectively,which satisfied the requirements of industrial production.

Effect of Multi-Hydroxyl Polymer-Treated MUF Resin on the Mechanical Properties of Particleboard Manufactured with Reed Straw

The poor bonding performance between aqueous adhesives represented by melamine-urea formaldehyde(MUF)resins and reed straw hinders their applications in the field of non-wood-based panels.Multi-hydroxyl polymers are highly reactive and are often used as crosslinkers.This study fabricated a resin with a strengthened crosslinked structure by combining a multi-hydroxyl polymer and MUF resin prepolymer.The reed particleboard was prepared by using this resin as an adhesive and reed stalk as the matrix.The results show that neighboring molecules combined to form C–O–C bonds that strengthened the cross-linked structure of the resin.In addition,the viscosity of the resin was increased,and a continuous adhesive layer on the surface of reed particles was formed,which slowed the penetration of reed particles.The adhesive layer significantly improved the mechanical properties of the reed particleboard.The maximum modulus of rupture(MOR),modulus of elasticity(MOE),and internal bonding strength(IB)of the reed particleboard were 33.53,4126,and 0.79 MPa,respectively.The IB of the board was 3.3 times higher than that of the reed particleboard prepared with a conventional MUF resin.Reed straw is a non-wood biomass material that has the advantage of sustainable development and may replace woodbased materials to produce particleboard.This resin-prepared reed particleboard is expected to be used in areas such as custom furniture and engineering materials.

Self-Cross-Linked Tannin-Aminated Tannin Surface Coatings for Particleboard

Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many,if not all of the tannin hydroxyl groups with–NH_(2)groups.A tannin-aminated tannin(ATT)particleboard coating was then prepared by reacting raw tannin extract with aminated tannin extract and thus cross-linking the two by substituting tannin’s hydroxyl groups with the–NH_(2)groups on the aminated tannin to form–NH-bridges between the two.The resulting particleboard coating gave encouraging results when pressed at 180℃for 3 min.Conversely,the system in which tannin was reacted/cross-liked with urea(ATU)by a similar amination reaction did not perform as well as the ATT system,and this even when a higher curing temperature and longer hot press time were used.In particular its water repellence was worse probably due to the presence of urea and such a system with lower reactivity.Nonetheless,substituting the tannin–OHs with the urea–NH_(2)groups appeared to also take place.ATT gave better results than ATU as regards water repellence and mechanical resistance as shown by the cross cut test.The ATT system was shown to be between 95%and 98%biosourced.The difference appeared to be due,by TMA analysis,to the much faster formation of the ATT hardened network leading to a better cross-linked polymer coating.The chemical species formed for both the ATT and ATU system were studied by MALDI ToF and CP MAS^(13)C NMR.

Low-energy X-ray attenuation characteristics of Rhizophora spp.composites

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.

Cement-bonded particleboard with a mixture of wheat straw and poplar wood

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.

Biological performance of particleboard incorporated with boron minerals

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.

Preparation and properties of waste tea leaves particleboard

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）.

Use of amino silane coupling agent to improve physical and mechanical properties of UF-bonded wheat straw(Triticum aestivum L.) poplar wood particleboard

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）.

Gypsum-bonded particleboard manufactured from agricultural based material

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.

Observation and Analysis of Gypsum Particleboard using SEM

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.

No-Aldehydes Glucose/Sucrose-Triacetin-Diamine Wood Adhesives for Particleboard

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.

The effect of urea pretreatment on the formaldehyde emission and properties of straw particleboard

For manufacturing low-formaldehyde emission particleboard from wheat straw and urea-formaldehyde （UF） resins using urea treatment for indoor environments, we investigated the influence of urea treatment on the formaldehyde emission, physical and mechanical properties of the manufactured particleboard. Wheat straws were treated at three levels of urea concentration （5%, 10%, 15%） and 95℃ as holding temperature. Wheat straw particleboards were manufactured using hot press at 180℃ and 3 MPa with two types of UF adhesive （UF-45, UF-91）. Then the formaldehyde emission values, physical properties and mechanical properties were considered. The results show that the for- maldehyde emission value was decreased by increasing urea concentration. Furthermore, the results indicate that the specimens under urea treatment have better mechanical and physical properties compared with control specimens. Also specimens under urea treatment at 10% concentration and UF-91 type adhesive have the most optimum physical and mechanical strength.

Potential of utilization of the residues from poplar plantation for particleboard production in Iran

The composite board industry in Iran is obliged to use residues from forest operation as well as wood industry for competing with paper industry because of shortage of wood. In the present study we investigated the residues from poplar plantation used for particleboard production. Three kinds of wood materials, poplar branches, small di- ameter poplar wood （3-8 cm） and beech wood, were used in the experiment of particleboard production. The results demonstrated that the characteristic of particleboard made from poplar branches and small diameter wood is comparable to that made from mature beech wood. To avoid too much residual acid in the final board, the properties of boards produced with 1.5% hardener at 175℃ press temperature are acceptable, although the properties of particleboard produced with 2% hardener were higher than were higher than that of the board produced with lower hardener （1% or 1.5%）.. The MOR, MOE and IB of particleboard made from branches were measured as 14.57, 2015, and 1.32 MPa, respectively, while The MOR, MOE and IB of particleboard produced from small diameter poplar wood were 19.90, 2199, and 1.86 MPa, respectively. The thickness swelling of boards made from branches after 2 and 24 h im- mersion in water was 20.14% and 31.26%. The utilization of branches and very small diameter wood of poplar is recommended for the survival and developments of particleboard industry in Iran.