Volume 14 Issue 1

The wood sanding process entails a small reduction in the dimensions of the workpiece in the course of modifying its surface morphology, which affects the aesthetics and the subsequent application of a coating. However, sanding is costly, partly because it is performed empirically without standardization. Therefore, this study analyzed the influence of sandpaper factors on the behavior of wood surface roughness for Pinus elliottii. A complete factorial experiment was performed, varying two types of abrasives, aluminum oxide and silicon carbide, in three grit sizes (80, 100, and 120), and three sandpaper conditions (new, semi-new, and worn). The tests were performed using a flat sander with a pneumatic circuit and monitoring system for data acquisition, which were analyzed through multiple Tukey tests. The results were organized in a consultation table that compared the combination of factors analyzed, informing whether they produced roughness of the wood equal to or distinct from each other. The results showed that new aluminum oxide sandpapers with grit sizes of 80, 100, and 120 produced roughness of the wood different from each other, while the carbide did not. Therefore, there is no need to trade or buy silicon carbide sandpaper in these grit sizes.

The strengthening effect of basalt fiber-reinforced epoxy coatings was investigated with regard to their areal weight and position on the compression or tension side of plywood. Beach plywood was coated on one side with a basalt fiber-reinforced epoxy matrix. Two biaxial and one twilled fabric with areal weights of 170 g/m2, 210 g/m2, and 340 g/m2 respectively were used. The thickness of the plywood was 21 mm. The results showed the best reinforcing effect was obtained with the highest weight when mounted on the tension side of the parallel specimens. The bending strength of these specimens was improved by 15.7%. The perpendicular specimens were positively reinforced by the fiber-reinforced polymers on both the compression and tension sides. The tension reinforcement provided a higher deflection, which was further analyzed using digital image correlation. The evaluated data indicated significant displacement of the neutral axis. The impact strength of the parallel specimens was not improved by the reinforcement, but all of the reinforced perpendicular specimens were significantly strengthened.

Thermoplastic elastomer (TPE), made from ethylene propylene diene monomer (EPDM) and polypropylene (PP) based on reactive blending, has excellent processing performance and characteristics and a wide range of applications. However, there are currently no reports in the literature regarding the usage of TPE in making composite boards. In this paper, EPDM, PP, and ammonium lignosulfonate (AL) were used as the raw materials, polyethylene wax was used as the plasticizer, and a dicumyl peroxide vulcanization system with dynamic vulcanization was used to make a new kind of composite material. This research studied the influences of the PP and AL contents on the crystallization behavior, mechanical properties, and rheological properties of the composites. The results showed that the PP content had a noticeable impact on the performance of the composites. The AL content had a major impact on the modulus of elasticity of the composite board. Accordingly, this kind of composite material can be used as an elastomer material for the core layer of laminated flooring.

Understanding the dissolution of hemicellulose in ionic liquids (ILs) is important in order to explore efficient utilization of ILs for fractionating lignocellulose and extracting hemicellulose. In this study, three ILs, namely 1-butyl-3-methylimidazolium chloride (BmimCl), 1-butyl-3-methylimidazol-ium bromide (BmimBr), and 1-butyl-3-methylimidazolium iodide (BmimI), were used as solvents to dissolve bamboo hemicellulose over the temperature range of 80 °C to 150 °C. Representative hemicellulose with a solubility higher than 9.0 g/100 g IL was regenerated and characterized. The interaction between the hemicellulose and ILs was evaluated using carbon-13 nuclear magnetic resonance. The results showed that the solubility of hemicellulose in the ILs was in the following order: BmimCl > BmimBr > BmimI. Though moderate degradation of the hemicellulose possibly occurred during dissolution, the main chain of the hemicellulose was almost unchanged. The enhanced solubility of the hemicellulose was because of the formation of hydrogen bonds between the hydroxyl proton of the hemicellulose and anion of the ILs.

Effluent found in the pulp and paper industry can cause considerable damage if it is discharged untreated, because of the high biochemical and chemical oxygen demands. Electrocoagulation is a physicochemical process widely used in industrial wastewater treatment. The removal of different pollutants depends on the sample type and operating conditions. The aim of this research was to evaluate the efficiency of an electrocoagulation system for COD removal from recycled paper production effluent via aluminum and iron electrodes. Different operational parameters, such as the electrolysis time (5 min to 15 min), current density (7 A/m2 to 11 A/m2), and distance between each electrode (5 mm to 20 mm), were evaluated. The turbidity, total suspended solids, chlorides, sulfates, and COD had removal efficiencies of 92.7%, 91.3%, 70.4%, 66.6%, and 64%, respectively. A polynomial model was generated to estimate the optimum conditions for COD removal. The optimum times for the current densities 7 A/m2, 8 A/m2, 9 A/m2, 10 A/m2, and 11 A/m2 were 39.5 min, 39.5 min, 35.7 min, 34.1 min, and 32.8 min, respectively, with a 15-mm electrode gap.

A broader utilization of wood can be achieved by eliminating its drawbacks such as low dimensional stability with changing moisture content and low durability against various bio-organisms. Heartwood formation is nature’s solution that functions through biosynthesis and accumulation of some phenolic compounds in the cell walls, leading to more durable and stable wood. In this study, a natural flavonoid molecule, chrysin, was used to improve Scots pine wood properties. Hydrophobic chrysin was impregnated into wood after a pre-treatment. The chrysin modification reduced the water uptake of the wood cell walls by up to 33% and increased the dimensional stability of the Scots pine by up to 30%. Infrared spectroscopic analysis revealed the chemical characterization of the bio-inspired modification. In contrast to the many modification methods that establish covalent bonds between hydroxyl groups of wood polymers, chrysin was bulked into wood cell walls and stabilized by intermolecular interactions.

Alkali lignin pyrolysis oil (PO) was subjected to a sequential extraction method in which PO was separated into water soluble (WS), water insoluble (WI), methanol soluble (MS), methanol insoluble (MI), dichloromethane soluble (DS), and dichloromethane insoluble (DI) subfractions via combinations of water and organic solvents (water, methanol, and dichloromethane). Several analytical techniques were used to characterize PO and its subfractions. Elemental analysis showed that the higher heating value (HHV) of DS was highest, and there was higher aromaticity in the MI fraction, while the DI fraction had lower aromaticity. Interestingly, gas chromatography–mass spectrometry (GC–MS) and positive ion electrospray high resolution mass spectrometry (ESI+–HRMS) analyses showed that both the MI and DI subfractions were lignin-derived oligomers, which accounted for 25.0% of the total mass of the original PO. Additionally, the oligomers in the PO were mainly composed of dimers to pentamers. The secondary tandem MS/MS (MS2) experiments revealed that the m/z 360 is a dimer linked by coniferyl alcohol and a ferulate linkage, and no further fragmentation was observed in both the m/z 475 and 701 due to the rigidity of these structural motifs.

This work investigated the feasibility of manufacturing composite cross-laminated timber (CCLT) from bamboo and a western hemlock and amabilis fir mix (hem-fir). Bamboo parallel strand lumber (bamboo PSL) was first fabricated as the surface laminae of CCLT. No. 2 and Btr 2×6 western hem-fir dimension lumber was imported from British Columbia (BC), Canada. The lumber was then sorted and further dried to form the inner laminae of CCLT. Multiple 800 × 800-mm CLT billets were fabricated using a commercial single-component polyurethane (PUR) adhesive. Block shear and delamination tests were conducted to examine the bond quality and durability of bamboo-wood CCLT. The results demonstrated that it is technically feasible to manufacture bamboo-wood CCLT with acceptable bond quality (shear strength, wood failure percentage, etc.) and delamination. Further studies should focus on the optimization of process parameters for manufacturing and surface treatment to improve the bond quality and durability and quantify the mechanical performance of bamboo-wood CCLT with a full-size production trial.

Bamboo-like glulam beams with hollow section units and intermittent internal reinforcement pieces were produced with small-diameter larch-wood pieces and one-component polyurethane. To better understand the design reliability, the failure mode, ultimate bearing capacity, and application potential were evaluated. Three types of beams (solid glulam, hollow glulam, and bamboo-like rectangular glulam beams) were compared and analyzed in this work. Stiffener pieces glued inside the bamboo-like beam were found to increase the bearing capacity and improve the failure mode relative to the hollow glulam beam. Comparison of the hollow section with a similar outside diameter showed that the ultimate bearing capacity increased by approximately 12.3% when the spacing between the stiffeners was 270 mm, and the ultimate bearing capacity increased by approximately 18.0% when the spacing between the stiffeners was 135 mm. Compared with the solid timber beams, wood consumption was reduced by 26.4% and 25.7% for the hollow and bamboo-like glulam beams, respectively. Also, a parameter analysis of the reasonable spacing and thickness of the stiffener was proposed by the finite element method.

A sulfonic carbon-based catalyst (C-SO3H) was successfully prepared by sulfonating incompletely carbonized sugarcane bagasse. The optimized catalyst of high activity in the esterification of levulinic acid (LA) with ethanol was produced under sulfonation at 150 °C for 15 h with a 75 mL/g sulfonation ratio. The prepared catalysts were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM), and elemental analysis (EA). The bagasse-carbonized catalyst was porous, and the porous structure remained unchanged after sulfonation treatment. Moreover, the introduced acidic group was the catalytic center. A high yield of ethyl levulinate (ELA) of 88.2% was obtained at 120 °C for 9 h. The sulfonic carbon-based catalyst could be reused at least five times and still exhibited great stability. The application of the sulfonic carbon-based catalyst was not only the effective use of biomass resources but also promoted the production of various high value chemicals.