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In this study, the suitability of walnut shell as a renewable agricultural residue for panel manufacturing was investigated. Particleboards containing different walnut shell particle ratios (0%, 10%, 20%, 30%, 40% and 100%) were made using urea–formaldehyde (UF) resin. Some chemical properties of walnut shell (holocellulose, α cellulose, lignin and ash contents, alcohol–benzene solubility, 1% NaOH solubility, hot and cold water solubility), mechanical (modulus of rupture, modulus of elasticity and internal bond strength) and physical properties (thickness swelling and water absorption) of the particleboard were determined. The addition of walnut shell particles greatly improved the water resistance of the panels. However, flexural properties and internal bond strength decreased with increasing walnut shell particle content. The results indicated that panels can be manufactured utilizing walnut shell particles up to 20% without falling below the minimum EN Standard requirements of mechanical properties for general purpose use. Conclusively, walnut shell, an annual residue, could be utilized with mixture of wood particles in the manufacture of particleboard used for outdoor environments due to lower thickness swelling and water absorption.

The aim of this study was to determine the performance of three-layer particleboard made from wheat straw and veneer splinters, as waste materials. For the purpose of evaluation, compositions of wheat straw and beech veneer splinters at different mixture rates were compared for some of properties. Physical (thickness swelling and water absorption) and mechanical properties (modulus of rupture, modulus of elasticity, internal bond and impact strength) of the boards were evaluated. Effects of mixing ratios of fibrous material and press temperature on the above-mentioned properties were also investigated. The mixing ratios of beech veneer with wheat straw were 100%:0%, 75%:25%, 50%:50%, 25%:75% and 0%:100%, respectively. A commercial urea–formaldehyde (UF) adhesive was used as binder. A total of 10 experimental boards with an average target density of 0.70 g cm−3 across all mixtures were fabricated. All the mechanical and physical properties of the boards were improved when the press temperature was increased from 140 to 170 °C. Analysis of data revealed that the mechanical properties were significantly different among the board types. With the exception of modulus of elasticity, the other properties were decreased by the addition of wheat straw particles. In general, water absorption and thickness swelling decreased with the increase of wheat straw content. The presence of wheat straw in the particleboards resulted in higher water absorption and thickness swelling. Finally, it can be stated that wheat straw and beech veneer splinters have potential as supplement fibrous materials, in combination with wood particles for particleboard manufacturing and indoor applications.

The main objective of this study is to investigate some of applied properties of experimental particleboard panels made with bagasse, as an alternative fibrous raw material. Modulus of elasticity (MOE), modulus of rupture (MOR), internal bond strength (IB) and thickness swelling (TS) of the specimens were evaluated. In addition, average roughness (Ra) and mean peak-to-valley height (Rz) were used to determine quantitatively surface characteristics of the panels. Three-layer mats with target density of 0.70 g/cm 3 were formed by using fine chips for the face layer (25 wt.%) and coarse chips for the core layer (50 wt.%). Variable factors were as wood species (bagasse, poplar and mixed hardwood species), moisture content of mat (face layer: 12%, 14% and core layer: 9%, 11%) and press time (6 and 8 min). Statistical analysis showed that all variable factors exerted a significant influence on MOR, MOE, IB, TS, Rz properties of the boards as a single factor. Panels made with bagasse particles had superior mechanical and physical properties compared to the poplar and mixed hardwoods particles. Bagasse boards exhibited better surface roughness, having lower Ra and Rz values, than those made with poplar and mixed hardwoods particles.

The objective of this work is to evaluate the mechanical and physical properties of three-layer boards made with wheat straw and bonded with a tannin-based adhesive. The mechanical properties of panels were evaluated by the static bending (modulus of rupture – MOR and modulus of elasticity – MOE) and the internal bond (IB) tests. Physical properties such as water absorption (WA) and thickness swelling (TS) in water were determined. In general, all types of straw panels made produced in this work met the MOR, MOE, IB and TS requirements for general uses according to European standards. Although, wheat straw boards made with tannin-modified PF resins had slightly poorer mechanical properties compared to the boards made with pure PF, the T 10% PF resin showed higher bond ability than other modified PF resins. The highest MOR, MOE, IB and the lowest WA and TS were achieved at a 12 min press time and by using T 10% PF resin. An increase in the press time positively affected the physical and mechanical properties of the panels produced. With respect to the findings of this study, it may be stated that wheat straw can be used as a promising raw material for panel production with the use of a tannin-modified PF adhesive.