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This study investigated the effects of shredded waste office paper as a raw material on the physical and mechanical properties of fiberboard. Two amounts of urea formaldehyde (UF) resin (10 and 15%) and five shredded waste office paper/wood fiber mixing ratios (0/100, 25/75, 50/50, 75/25, and 100/0) were selected. The findings showed that all characteristics of boards were improved with an increase in resin content at various wastepaper participation ratios. The 15% UF-bonded board with 100% wood fiber had the highest modulus of rupture (MOR) value, but there was no statistically significant difference between it and the board with 50% wastepaper. The modulus of elasticity (MOE) values of the 15% UFbonded boards increased as the wastepaper participation ratio increased, and the highest was obtained from the board with 75% wastepaper. The highest internal bond (IB) strength value was also recorded from the 15% UF-bonded board with 50% wastepaper. This was due to the presence of sufficient bonding potential and smoother surfaces in the shredded wastepaper, which allowed for a synergistic interaction between the wastepaper and wood fiber. [ABSTRACT FROM AUTHOR]

Wood plastic composites (WPCs) were prepared by extrusion molding with eucalyptus powder, polyvinyl chloride (PVC), and silica as additives. The mechanical properties, creep behavior, thermal properties, and crosssection microstructure of the composites were analyzed by universal testing machine, thermogravimetric analyzer, and scanning electron microscope. The results show that with the increase of silica content, the tensile strength, bending strength, and impact strength of the WPCs first increased and then decreased. When the silica content was 3.0%, the tensile strength, bending strength, and impact strength of WPC reached the maximum values of 27.5 MPa, 48.8 MPa, and 4.18 KJ · m-2, respectively, which represented increases of 12.6%, 9.4%, and 20.1%, respectively, compared with those without silica. When the stress was 13.4 MPa, the strain value of 3.0% SiO2-eucalyptus/PVC wood plastic composite was 3.3 times that of 4.46 MPa and 1.7 times that of 8.92 MPa. The pyrolysis process of eucalyptus/PVC WPCs showed a similar trend with different silica content. [ABSTRACT FROM AUTHOR]

An albumin adhesive derived from animal blood was used for the first time for the production of two kinds of fiberboard in a dry process: medium-density fiberboard (MDF) and wood fiber insulation board (WFI). Additionally, the curing for WFI was completed using an innovative hotair/hot-steam (HA/HS) process. There is a general importance to develop alternatives to substitute common binding agents, such as urea-formaldehyde (UF) or polymeric methylene diphenylene diisocyanate (pMDI) resins, and to develop value-added opportunities for such waste material from slaughterhouses. An adhesive analysis was performed to understand the curing reaction of these protein adhesives, which showed good properties in regards to viscosity or gel time. The physical-mechanical results showed on the one hand that the albumin adhesive could compete with UF-bonded MDF regarding tensile strength and modulus of rupture in conformity to the European Standard, but it failed to meet requirements for thickness swelling. The albumin adhesive also can compete with pMDI bonded WFI regarding tensile and compression strength, but it showed non-viable results for short-term water absorption. [ABSTRACT FROM AUTHOR]

As the demand increases for low energy green buildings, such as passive housing, the development of new insulation systems based on natural materials is underway. In this study, 20-mm-thick wood fiber insulation board (WIB) samples of different densities were prepared using melamineformaldehyde-urea (MFU) resin adhesives. The resin contents were fixed at 35% and the target densities were 0.10 g/cm³, 0.15 g/cm3, 0.20 g/cm³, and 0.25 g/cm³. The thermal conductivities of the WIBs gradually increased as the density increased. The formaldehyde (HCHO) emissions of all the WIBs indicated that they were of "Super E0" (SE0) grade, but the quantity of the HCHO emissions slightly increased as the density increased. The thickness swelling of all the WIBs was stable at less than 3%, and the bending strength linearly increased as the WIB density increased. A notable decrease in the water absorption rate was observed between the lower and higher density WIB samples. Based on the results of the cone calorimeter tests, the carbonization depth ratio and the weight loss rate remarkably decreased as the density increased. Therefore, the optimum WIB density was in the range of 0.15 g/cm³ to 0.20 g/cm³ to provide adequate insulation performance as well as human and structural safety. [ABSTRACT FROM AUTHOR]

Wood-fiber insulation boards can be utilized as a core construction material. They provide a comfortable and safe residential space and reduce energy consumption because of the ecofriendly nature and high heat insulation. In this study, wood-fiber insulation boards were prepared with different types of adhesive (melamine-urea-formaldehyde (MUF), phenol-formaldehyde (PF), emulsifiable 4,4' methylene diisocyanate (eMDI), and latex resins), and the physical and heat insulation properties, toxic chemical emissions, and combustion characteristics were analyzed. The different adhesive types had no major effects on the insulation. With regard to the toxic emissions, all wood-fiber insulation boards showed the best rating possible except for the PF resin. In the cone-calorimeter test, the wood-fiber insulation board prepared with MUF showed a lower total heat release, mean heat release rate, smoke release, and CO and CO2 yields than the other samples because of the early formation of the carbonized layer. Based on the comprehensive evaluation, the MUF adhesive is the best choice for wood-fiber insulation boards. [ABSTRACT FROM AUTHOR]

The production of environmentally friendly thermal insulation boards is important for the building industry to reduce its environmental impact. The primary objective of this study was to test the feasibility of producing woodbased insulation panels as well as to use fungi as a binding agent and to explore whether a bio-based composite could be a viable alternative to the standard traditional foam insulation board and more expensive wood fibreboards (mainly available in European markets). Experiments were conducted to determine which combinations of wood fibers from selected northern tree species, wood decay fungi, and growth conditions were most suitable for panel making. The results showed that under the determined optimal growth conditions, Polyporus arcularius and Trametes suaveolens on birch wood shavings provided the best combination. Outcomes from initial physical screening tests, particularly thermal conductivity, suggested that these panels had a comparable performance to traditional insulation material. [ABSTRACT FROM AUTHOR]

Wood fibers were prepared as core materials for a vacuum insulation panel (VIP) via a dry molding process. The morphology of the wood fibers and the microstructure, pore structure, transmittance, and thermal conductivity of the wood fiber VIP were tested. The results showed that the wood fibers had excellent thermal insulation properties and formed a porous structure by interweaving with one another. The optimum bulk density that led to a low-cost and highly thermally efficient wood fiber VIP was 180 kg/m3 to 200 kg/m3. The bulk density of the wood fiber VIP was 200 kg/m3, with a high porosity of 78%, a fine pore size of 112.8 µm, and a total pore volume of 7.0 cm3·g-1. The initial total thermal conductivity of the wood fiber VIP was 9.4 mW/(m·K) at 25 °C. The thermal conductivity of the VIP increased with increasing ambient temperature. These results were relatively good compared to the thermal insulation performance of current biomass VIPs, so the use of wood fiber as a VIP core material has broad application prospects. [ABSTRACT FROM AUTHOR]

9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) graft γ- amino propyltriethoxy silane (APS), γ-glycidoxy propyltrimethoxy silane (GPS), and methacryloyl propyltrimethoxysilane (MPS) were synthesized and introduced on the surface of wood fiber. DOPO-g-APS (GPS and MPS) treated wood fibers (DAWF, DGWF, and DMWF) were used to prepare composite phenolic foams (DAWFCPF, DGWFCPF, and DMWFCPF). The chemical structures of DOPO-g-APS (GPS and MPS) were confirmed by Fourier transform infrared (FT-IR) spectra and nuclear magnetic resonance. The structures of DAWF, DGWF, and DMWF were confirmed by FT-IR. The diffraction peak positions were basically unchanged, but the crystallinity was slightly increased. Compared with WF, thermal stabilities were increased. The residue (800°C) was slightly reduced. Compared with phenolic foam, the properties of DAWFCPF and DGWFCPF were better than others. Besides compression strength, the mechanical properties were increased dramatically, limited oxygen index was slightly enhanced, the cellular pore distribution was more regular, and the size of bubble cell was smaller and more uniform. By comprehensive analysis, the properties of DAWFCPF were best in all samples. The interfacial compatibility was significantly improved between DAWF and phenolic resin. These results confirmed that DOPO-g-APS is a suitable material for treating wood fibers and preparing composite phenolic foams. [ABSTRACT FROM AUTHOR]

Wood fibers were modified with alkaline solution and silane coupling agent to study changes on the fiber surface and the influence of these treatments on the mechanical properties, flame resistance, thermal conductivity, and microstructure of wood fiber-phenolic foam composites. Test results indicated that the lignin, waxes, hemicelluloses, and other impurities from the fiber surface were partially dissolved and removed. The mechanical properties of treated wood fiber-phenolic foam composites increased dramatically, the cellular pore distribution was more regular, the size of bubble cells was smaller and more uniform, and the thermal conductivity was reduced, and, in particular, the fragility of treated wood fiber-phenolic foam composites decreased. However, with increasing wood fiber content, the mechanical properties and limited oxygen index (LOI) of composite foam decreased. By comprehensive analysis, it was shown that the interfacial compatibility between the fibers and phenolic resin was improved. Nevertheless, the amount of wood used could not be too high, and the optimum amount was approximately 5%. [ABSTRACT FROM AUTHOR]

To develop a wood-based electromagnetic shielding composite, in-situ electroless plating was used to plate nickel onto the surface of expanded graphite (EG) to obtain nickel-plated EG (Ni-EG), and the Ni-EG was mixed with wood fiber to manufacture the composite. The optimal plating formula was as follows: 20 g/L NiSO4·6H2O as the main salt, 60 g/L N2H4·H2O as the reducing agent, 50 g/L Na3C6H5O7·2H2O as the complexing agent, 40 g/L CH3COONa·H2O as the buffering agent, pH value 11, and a temperature of 90 °C. These conditions yielded the highest quality of nickel coating (3.57 g). As EG concentration increased from 2 to 10 g/L, the percentage of the Ni-EG in the composite was 60%, the thickness of the composite was 2 mm, the density was 0.9 g/cm3, the magnetic properties and resistivity of the Ni-EG decreased from 29.5 to 5.57 emu/g and 80.2 to 10.7 mΩ·cm, respectively, and the electromagnetic shielding effectiveness (SE) and the reflectivity of the composite increased from 55 to 60 dB and −3.6 to -1.8 dB, respectively. Consequently, the introduction of nickel is suitable for improving the absorbing performance of Ni-EG/wood fiber composites, leading to better SE in a broad frequency range. [ABSTRACT FROM AUTHOR]

As the main raw material for fiberboard, the hygroscopicity of wood fibers is of great concern. In this study, three alkoxysilanes with different chain lengths--methyl trimethoxy silane (MTMS), octyl trimethoxy silane (OTMS), and dodecyl trimethoxysilane (DTMS)--were used respectively to treat wood fibers to reduce their hygroscopicity and surface hydrophilicity. After alkoyxilane properties were evaluated, the chemical structures, surface groups, and morphology and distribution of alkoxysilanes within modified wood fibers were characterized using scanning electron microscopy (SEM) coupled with energy-dispersed Xray analyzer (EDXA), Fourier Transform Infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The study found that after modification, the moisture adsorption rate of wood fibers had decreased and the surface hydrophobicity of the fibers had been promoted. The fibers modified with MTMS adsorbed the least amount of moisture. The study also found that while hydrolyzed silane penetrated into wood fibers and reacted with their chemical components, long chains of the silane hindered the degree of that penetration. [ABSTRACT FROM AUTHOR]

Bio-fibers have been used for some time to reinforce thermoplastic composites; such structures are being used in a variety of commercial applications. In this study, wood fiber and flax fiber were used to reinforce high-density polyethylene (HDPE) formed by extrusion. The flexural, tensile, and impact resistance properties of the resulting flax fiber/wood fiber/HDPE (F/W/HDPE) composites were measured and modeled as a function of the volume fraction of flax fiber. Finally, the correctness of the modified model was verified. Based on the measurement data, the volume fraction of flax fiber was shown to play an important role in determining the mechanical properties of these composites. With increasing flax fiber volume fraction, the flexural strength, tensile strength, tensile modulus of elasticity, and impact resistance of the composites generally increased. However, the flexural modulus decreased. Based on the rule of mixtures (ROM) model, two coefficients were introduced and a new curve-fitting model was established based on measurements of macrostructure. Compared with the traditional ROM model, the new model developed in the present study could describe the flexural strength, tensile modulus, and impact strength of F/W/HDPE composites more accurately. [ABSTRACT FROM AUTHOR]

Intelligent resource usage is one of the most challenging tasks for the wood-based panels industry. With respect to this issue, leather shavings, derived during leather preparation, are a promising new raw material, as they offer not only high availability, but also potentially enhance material properties such as panel fire retardancy. In order to improve the performance of these emerging panel binder materials, an understanding of chemical interactions between the different constituents is crucial. This paper investigates the chemical changes that occur during hot-pressing of wood and leather in combination with lignin by means of solid state 13C NMR spectroscopy. These constituents, their binary mixtures, and the influences of panel pressing temperature and pressure commonly used in panel production were investigated. The study showed characteristic chemistry and features of these constituents, quantifying the impacts of both heat and pressure on their interactions. Primarily, analysis revealed that lignin readily connects with both the wood and leather components. Lignin induces chemical change within the protein structure of leather, resembling tanning reactions, or protein complexation. By analogy, it was deduced that this interaction also takes place between leather and the lignin-rich wood fibre surface. This effect may be beneficial in industrial-scale production through improving resin binding properties during panel consolidation. [ABSTRACT FROM AUTHOR]

When increasing the wood fiber (WF) content in extruded wood fiber/plastic composites (WPC) foams, a good balance between reducing the cost and obtaining good cell morphology should be maintained. This study examines the relationship between WF content and the foam morphology in WPC foams. The role of WF as cell nucleating agent at low concentrations (10 wt.%) was observed, as WPC foam with 10 wt.% WF had lower average cell size and higher cell density than neat HDPE foams. Increasing the WF content further, decreased the average cell size and cell density, and increased the foam density of WPC foams. These results were linked to the rheological properties and crystallization behavior of HDPE and WPC with different WF content. [ABSTRACT FROM AUTHOR]

Bio-based polyurethane (PU) spray foam insulation was prepared with soy polyol. The effects of adding wood fiber and water on the thermal and mechanical properties of the insulations were studied. The decomposition temperature (Td) of the foams increased with fiber reinforcement due to a higher degree of crosslinking. Alternatively, different fiber length contributed to different crosslinking. In addition, the neat foams, which didn't contain wood fibers, had exceptional thermal stability with the increase of the amount of H2O by forming more stable polyurea adducts. In addition, PU spray foam blown with a larger content of H2O had higher compressive strength by forming a stiffer phase. Still, PU spray foam reinforced with fiber also had superior compressive strength due to the fiber framing into the foam struts. The effect of the fiber length on the compressive strength was evaluated. The degree of complex networks was influenced by the fiber length. However, the tensile strength was weakened with the addition of wood fiber. [ABSTRACT FROM AUTHOR]

Environmentally friendly polyurethane (PU) spray foam insulation was prepared by substituting petrochemical polyol with soy-based polyol. The effects of adding wood fiber and water on the cell morphologies were studied. Cell size increased with the presence of wood fiber, but it decreased with an increase of water (H2O). Still, shorter fiber decreased in foam density but increased in cell size and open cell content. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study to use virgin wood and OCC fiber for particleboard production. Three-layer boards, with wood and OCC fiber on the surface, were fabricated. The type of applied furnishes at surface layers, moisture, and adhesive content were considered as variables, and their effects on roughness of manufactured particleboards were examined. The panels were produced with 10% and 12% urea formaldehyde (UF) adhesive at 10% and 14% moisture content. The surface characteristics were investigated. The results indicated that wood and OCC fiber utilization on the surface layer gave smoother surfaces than a control board with fine wood particles on its surface. The surface roughness decreased as adhesive and moisture content increased. [ABSTRACT FROM AUTHOR]