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Development and characterization of novel particleboard panels manufactured from organic waste with fiberglass reinforcement
Indentation Hardness and Elastic Recovery of Some Hardwood Species
The purpose of the study was to measure the Brinell hardness (HB) of six wood species and evaluate the ability to recover the depth of the imprint (self-re-deformation). Straight-grain clear samples of ash, beech, alder, birch, iroko, and linden wood were prepared. Measurements were made in the three main reference timber cross-sections: radial (R), tangential (T), and axial/longitudinal (L) and with two measuring loads of 30 kG and 100 kG (294.2 N and 980.7 N). The tested wood species could be classified into hard (ash, beech), medium-hard (alder, birch, iroko), and soft (linden) wood species. The HBs of each tested wood species differed in the cross-sections, i.e., side hardness (R, T) and end hardness (L). Higher HB values were obtained at 100 kG load in all species and all three cross-sections. The lowest influence of the measurement force value on the HB value was revealed for the soft wood species (linden: 107–118%). This influence was visible for the other five medium-hard and hard wood species, ranging from 125% to 176%. The percentage of temporary imprint in total imprint depth (x/H) varied from 12 to 33% (linden 12–18%—the lowest self-re-deformation ability; beech 25–33%—the highest self-re-deformation ability). The results of this study underline that the higher the density of the wood, the higher the Brinell hardness, and, simultaneously, the greater the measurement force used, the higher the Brinell hardness measured. The ability of self-re-deformation in wood’s R and T cross-sections depends on the wood density and the measuring force used. In contrast, this ability only depends on the wood density in the L cross-section. Those observations imply that the compaction of the cell structure during side compression is mainly non-destructive, while the longitudinal deformation of the cell structure (the buckling of cell walls and fracture of ends of the cells) is to a great degree destructive and irreversible. These results can be used in the construction and furniture sectors, especially when designing products and planning the woodworking of highly loaded wood floors and furniture elements.
Characteristics of Three Bamboo Species and Their Potential as Raw Materials for Oriented Strand Board Production
Synthesis and Application of Activated Charcoal from Indonesian Sugar Palm Bunches (Arenga longipes) as a Potential Absorbent for Heavy Metals
Quantifying the finest particles in dust fractions created during the sanding of untreated and thermally modified beech wood
This article deals with the fractionation of wood dust by sieve after sanding. Dust from untreated beechwood was compared to dust from thermally modified beechwood (at 200 °C for 3 h). The authors hypothesized that the thermal modification changes the particle size distributions of the dust sieve fractions and that all the dust sieve fractions contain the finest particles, which are suspendable in the air and are potentially respirable. To obtain dust for testing, both wood materials were sanded with P120 paper at a belt speed of 14.5 m/s and a pressure of 0.65 N/cm2. A set of sieves with aperture sizes of 25, 80, and 250 µm were used to separate the dust into sieve fractions with grain sizes less than 25 µm, 25 to 80 µm, 80 to 250 µm, and greater than 250 µm. The content of the finest particles in the fractions was measured via a laser particle sizer. Both dusts had similar particle size distributions. In addition, each investigated fraction of both dusts contained the finest particles, i.e., less than 10 µm. It follows that the laser analysis method may be necessary to correctly assess the occupational risk at a sanding.
Characterisation of Wood Particles Used in the Particleboard Production as a Function of Their Moisture Content
The properties of particleboards and the course of their manufacturing process depend on the characteristics of wood particles, their degree of fineness, geometry, and moisture content. This research work aims to investigate the physical properties of wood particles used in the particleboard production in dependence on their moisture content. Two types of particles currently used in the production of three-layer particleboards, i.e., microparticles (MP) for the outer layers of particleboards and particles for the core layers (PCL), were used in the study. The particles with a moisture content of 0.55%, 3.5%, 7%, 10%, 15%, and 20% were tested for their poured bulk density (ρp), tapped bulk density (ρt), compression ratio (k), angle of repose (αR), and slippery angle of repose (αs). It was found that irrespective of the fineness of the particles, an increase in their moisture content caused an increase in the angle of repose and slippery angle of repose and an increase in poured and tapped bulk density, while for PCL, the biggest changes in bulk density occurred in the range up to 15% of moisture content, and for MP in the range above 7% of moisture content, respectively. An increase in the moisture content of PCL in the range studied results in a significant increase in the compression ratio from 47.1% to 66.7%. The compression ratio of MP increases only up to 15% of their moisture content—a change of value from 47.1% to 58.7%.
Physical and Mechanical Properties of Particleboard Produced with Addition of Walnut (Juglans regia L.) Wood Residues
The depletion of natural resources and increased demand for wood and wood-based materials have directed researchers and the industry towards alternative raw materials for composite manufacturing, such as agricultural waste and wood residues as substitutes of traditional wood. The potential of reusing walnut (Juglans regia L.) wood residues as an alternative raw material in particleboard manufacturing is investigated in this work. Three-layer particleboard was manufactured in the laboratory with a thickness of 16 mm, target density of 650 kg∙m−3 and three different levels (0%, 25% and 50%) of walnut wood particles, bonded with urea-formaldehyde (UF) resin. The physical properties (thickness swelling after 24 h) and mechanical properties (bending strength, modulus of elasticity and internal bond strength) were evaluated in accordance with the European standards. The effect of UF resin content and nominal applied pressure on the properties of the particleboard was also investigated. Markedly, the laboratory panels, manufactured with 50% walnut wood residues, exhibited flexural properties and internal bond strength, fulfilling the European standard requirements to particleboards used in load-bearing applications. However, none of the boards met the technical standard requirements for thickness swelling (24 h). Conclusively, walnut wood residues as a waste or by-product of the wood-processing industry can be efficiently utilized in the production of particleboard in terms of enhancing its mechanical properties.