Volume 9 Issue 1

A study was designed to examine the practical effects on bending and compression perpendicular to the grain of heating and treatment with preservative agents. Red oak and sweetgum were steamed to an internal temperature of 71 °C. Samples were subsequently treated with creosote or ammoniacal copper zinc arsenate (ACZA) while still hot. Samples were tested in bending and compression perpendicular to the grain using ASTM standards. The data indicate no severe reduction in bending properties of red oak or of the compression properties of sweetgum or red oak heated and then treated with ACZA or creosote.

High-value wood veneer is used in the furniture and automobile interior industries for decorative purposes. Due to mechanical restrictions, veneer application on surfaces is limited to simple shapes. In the last century, many approaches were developed to improve the moulding behaviour of veneer. However, all of these processes face several difficulties. Currently, water is primarily used for veneer plasticization, with the disadvantages of shrinkage and cracks due to drying. Furthermore, products often fail during material climate testing due to set recovery. Thus, a veneer modification process was considered combining plasticization, moulding, and shape fixation of veneer with reduced set recovery. To accomplish this, veneers were impregnated with furfuryl alcohol/maleic anhydride solutions to improve plasticization and moulding properties. Subsequently, veneers were moulded, and the realized shapes were fixed by temperature-induced acid-catalyzed polymerization. Due to the polymer in the cell wall, set recovery of all modified samples was noticeably reduced compared to reference samples plasticized with water prior to moulding. The degree of set recovery reduction due to modification varied with the modification intensity. Samples with higher weight percentage gain (WPG=126.4%) were more stable in the presence of moisture than samples with lower polymer yields (WPG=107.4%).

The objective of this study was to evaluate the uniformity of density distribution for Bamboo-bundle Laminated Veneer Lumber (BLVL) and its relationship to the stability of mechanical performance. A novel assembly style called was developed to enhance the density uniformity, and four different density levels for BLVL were examined by X-ray scanning. The results indicated that the homogeneity of density, the stability of mechanical performance, and the mechanical properties for BLVL could be effectively improved by assembling the bamboo bundles into layers and then combining the layers to make the lumber. The density uniformity in width and thickness directions increased with increasing target density. A negatively linear correlation between density and Coefficient of Variation (COV) of MOR and shearing strength was observed. Partial correlation analysis revealed that when controlling for the variability of density, the linear relationship between density and the COV of MOR became insignificant, and the degree of linear correlation between density and the COV of shearing strength decreased.

The aim of this study was to determine the influence of the application of glue, creating an elastic glue-line, on the deformation of wood-based panels asymmetrically veneered on one side with bamboo. The geometrical stability comparisons included multilayer composites used in the production of sliding doors, medium density fibreboard (MDF) panels, and chipboard used in the production of furniture. Chipboard panels retained their shape and stability after asymmetrical veneering, no matter which direction the veneer was placed in relation to the long edge. MDF boards retained their shape and stability only when they were veneered crosswise. The worst results were attained from composite boards, which bent in every case.

Bamboo residues were subjected to a microwave-assisted liquefaction process for the production of crude bio-polyols (CBP). The fractionated bio-polyols (FBP) were obtained by the removal of lignin derivatives from the crude bio-polyols (CBP) using a simple method. Polyurethane (PU) foams were successfully prepared from both CBP and FBP. The object of this study was to evaluate the effect of lignin derivatives in bio-polyols on the physical properties, thermal stability, and microstructure of PU foams. The results revealed that the PU foam made from CBP had a higher density and superior thermal stability compared to that made from FBP; however, they were also much more fragile. Scanning electron microscope (SEM) images indicated that the lignin compounds in the CBP had impact on the structure of the PU foam.

An environmentally compatible and size-controlled method has been employed for synthesis of superparamagnetic magnetite nanoparticles with prehydrolysate from corn stover. Various characterizations involving X-ray diffraction (XRD), standard and high-resolution transmission electron microscopy (TEM and HRTEM), selected area electron diffraction (SAED), and thermogravimetric analysis (TGA) have integrally confirmed the formation of magnetite nanoparticles with homogeneous morphology and the formation mechanism of magnetite only from ferric precursor. Organic materials in the prehydrolysate act as a bifunctional agent: (1) a reducing agent to reduce ferric ions to prepare magnetite with the coexistence of ferric and ferrous ions; and (2) a coating agent to prevent particle growth and agglomeration and to promote the formation of nanoscale and superparamagnetic magnetite. The size of the magnetite nanoparticles can be easily controlled by tailoring the reducing sugar concentration, reaction time, or hydrothermal temperature.

As the support for loading TiO2, bamboo-based activated carbon fibers (BACFs) were obtained from Phyllostachys pubescens Mazel after liquefaction using phenol, melt-spinning, curing carbonization, and H2O activation. TiO2/BACFs were prepared by the sol–gel method and characterized by SEM, XRD, FTIR, and XPS. Anatase TiO2 film with high photocatalytic activity was formed on the surface of BACFs, and the average crystallite size of the TiO2 film was 17 to 30 nm. The characteristic absorbance peaks of anatase TiO2 were observed at 1402 and 541 to 605 cm^-1 on the infrared spectrum of TiO2/BACFs. The surface of TiO2/BACFs was mainly comprised of C–C, C–O, C=O, and Ti-O bonds. With increased calcination temperature, the contents of element Ti and Ti-O bonds of lattice oxygen on the surface of TiO2/BACFs increased and then decreased. The degradation rate of TiO2/BACFs for methylene blue (MB) solution reached more than 98% after 7 h of UV illumination.

The Australian hardwood plantation industry is challenged to identify profitable markets for the sale of its wood fibre. The majority of the hardwood plantations already established in Australia have been managed for the production of pulpwood; however, interest exists to identify more profitable and value-added markets. As a consequence of a predominately pulpwood-focused management regime, this plantation resource contains a range of qualities and performance. Identifying alternative processing strategies and products that suit young plantation-grown hardwoods have proved challenging, with low product recoveries and/or unmarketable products as the outcome of many studies. Simple spindleless lathe technology was used to process 918 billets from six commercially important Australian hardwood species. The study has demonstrated that the production of rotary peeled veneer is an effective method for converting plantation hardwood trees. Recovery rates significantly higher than those reported for more traditional processing techniques (e.g., sawmilling) were achieved. Veneer visually graded to industry standards exhibited favourable recoveries suitable for the manufacture of structural products.

This work focused on the solution-sensitivity and the comprehensive mechanism of lignin breakdown during the phosphoric acid-acetone pretreatment process using density functional theory calculations. The structures and properties of a-O-4 lignin, β-5-3 lignin, and β-βlignin were detected, which showed that the bond length follows the order: a-O-4 bond < β-5-3 bond < β-βbond, but a-O-4 lignin is more sensitive to solvent molecule thanβ–β lignin and β-5-3 lignin. The decomposition mechanism of a-O-4 lignin, β-5-3 lignin, and β–β lignin in different solutions showed that a-O-4 lignin decomposes much more easily than β-5-3 lignin and β–β lignin, acting as the most accessible and susceptible point of lignin. Further, the selectivity of decomposition of lignin depends markedly on the synergy of solution and position. The physical origin of the structure-selectivity of lignin in different solution can be rationalized in terms of both thermodynamics and kinetics. The reactions investigated in this work constitute a large database for understanding the chemistry of a-O-4 lignin, β-5-3 lignin, and β-βlignin, and their decomposition in different solutions.

The goal of this study was to prepare nanocomposites of rice straw coated with different percentages of Fe3O4 nanoparticles (Fe3O4-NPs) [1.0, 5.0, 10.0, and 20.0 wt. %]. In this process, the size of Fe3O4-NPs changed with varying volumes of NaOH (2M). The Fe3O4-NPs were precipitated with sodium hydroxide from a solution of Fe(II) and (III) chloride in water under ambient conditions and N2 gas by the quick precipitation method using urea as a stabilizer. The rice straw/Fe3O4 nanocomposites (NCs) prepared by this method had magnetic properties in percentages higher than ten (10 wt. %). When the volume of NaOH increased, Fe3O4-NPs with uniform size and better distribution could be prepared, which means that the size of the NPs decreased as the reducing agent was increased. Transmission electron microscopy (TEM) showed that Fe3O4-NPs in rice straw were spherical with diameters from 18.47 to 9.93 nm. The SEM results show that the structure of rice straw underwent no particular change. EDX indicated the presence of Fe3O4-NPs on the surface of rice straw. X-ray powder diffraction (PXRD) indicated that the magnetic Fe3O4-NPs were pure and that the particles were small. The FT-IR results showed that the Fe3O4-NPs were successfully coated on the surface of rice straw.