Research Articles

In order to simultaneously improve the strength and decoration properties of plantation wood, a multi-effect modifier was prepared by compounding acid red 18050(G) with melamine-modified urea formaldehyde resin (MUF). Various compounding methods for MUF synthesis such as adding dye with the first part urea (U1G) or with the second part urea (U2G), or direct blending with MUF resin (BG) were tested. Chinese fir plantation wood was impregnated with these modifiers separately, and its color, color fastness, and dyeing mechanism were studied. The results showed that G had good compatibility with MUF and could prolong its storage time, and all compound modifiers exhibited permeability and coloring effect on Chinese fir wood. Compared with G-dyed wood under the same conditions, all the compound dyed wood had better color fastness to water, and the U2G-dyed was the best, the color fastness to xenon light of U2G dyed wood was greatly improved.. Fourier transform infra-red (FTIR) analysis showed that compared with MUF-modified wood, the dye affected MUF hydroxyl-methylation reaction in U1G, lowered the polycondensation degree, and extended its storage time. The dye might have promoted the ionic reaction between resin amino and dye sulfonic groups in U2G, thus displaying better color fastness.

The feasibility of performing finger jointing of green rubberwood was considered with typical adhesives used for gluing kiln-dried wood. The effect of initial moisture content of rubberwood (12 ± 1.1%, 37.6 ± 3.2%, and 61.2 ± 6.1%), hot air oven-drying temperatures (60 °C, 80 °C, and 100 °C), and types of adhesives (polyurethane (PU) and emulsion polymeric isocyanate (EPI)) on bending and compressive properties of finger jointed rubberwood products were investigated. The controls were manufactured from 12 ± 1.1% moisture content rubberwood. The type of adhesives had no significant effect on the examined properties of the finger-jointed specimens. The initial moisture content had a slight effect on the modulus of rupture (MOR) and modulus of elasticity (MOE) of specimens bonded with EPI adhesive. The MOR of all types of specimens bonded with EPI adhesive were slightly lower, but their MOE tended to be slightly higher than the control. The drying temperature slightly improved the MOE of specimens bonded with EPI adhesive. The result suggests that the finger jointing process of green rubberwood using typical adhesives could be performed without notably reducing the strength of the final products compared with the control.

The main objective of this study was to investigate the key mechanical properties of cross-banded laminated veneer lumbers (LVL-C) manufactured from blending veneers recovered from sub-optimal native forest spotted gum and plantation hoop pine logs. The recovered veneers were separated into three grades based on their dynamic modulus of elasticity (MOE). Additionally, the spotted gum veneers were visually graded to evaluate whether a relationship exists between the MOE-based and visual grades. In total, six 12-ply reference LVL and six mixed-species 12-ply LVL-C panels were manufactured and analyzed for (i) flatwise and edgewise bending performance; (ii) bearing and tension strength perpendicular to the grain; and (iii) longitudinal-tangential shear strength. Little correlation was found between MOE-based and visual grades for the spotted gum veneers. The LVL- C showed flatwise and edgewise MOE up to 24% and 13% lower, respectively, than the reference mixed-species LVL. The flatwise and edgewise modulus of rupture were up to 39% and 19% lower, respectively. On average, the tensile and bearing strengths of the LVL-C were considerably higher than the hoop pine LVL and mixed-species LVL, with the former being approximately three times higher. The manufactured LVL-C showed markedly higher bending properties and tensile strengths than commercial LVL-C products.

Bamboo floorings are the most important industrial products in the bamboo sector. With the aim of providing a useful guide for the development of bamboo floorings, this study quantitatively assessed the environmental impacts of the two primary types of bamboo floorings, laminated flooring and scrimber flooring, using life cycle assessment (LCA) software SimaPro. The purpose of this study was to find out which type of bamboo flooring is more environmentally friendly through quantitatively analyzing the input and output of materials and energy during the whole life cycle of the two types of flooring products. The present study demonstrated that the majority of the environmental burdens were associated with the process of bamboo strip production for bamboo laminated flooring (59.3%), and the process of panel processing for bamboo scrimber floorings (56.9%). In terms of environmental loads, bamboo laminated flooring was considered more sustainable than bamboo scrimber flooring, as the total environmental loads of bamboo scrimber flooring was approximately 1.6 times that of bamboo laminated flooring.

Tungsten trioxide (WO3) nanosheets were deposited onto a wood surface by a solvothermal synthesis method using temperatures between 90 and 120 °C. These WO3 nanosheets were used to improve the color, as well as to enhance the photochromic characteristics and ultraviolet aging resistance of the wood. The results indicate that the WO3 nanosheets on the wood’s surface were affected by the treatment temperature. The formed nanosheets included nanoparticles and rod-shaped structures, which are highly crystallized. Different structures were generated in the nanosheets, which affected their functionality. The modified wood not only exhibited photochromic phenomena when excited by ultraviolet radiation, but also demonstrated resistance against ultraviolet light aging.

With the widespread use of wood-plastic composites, they are inevitably affected by aging during transportation and outdoor use. In this research, in order to improve the aging resistance of WPC, acrylate-styrene-acrylonitrile (ASA) was used as modifier (10 parts, 15 parts, and 20 parts). The effects of the ASA modification on the aging behavior of eucalyptus/polyvinyl chloride (PVC) composites was studied with simulated xenon lamp artificial aging conditions. Artificial aging caused the physical and mechanical properties of the composites to deteriorate. After 960 h of aging, the aging resistance of the ASA-modified WPC was better than unmodified WPC and the sample with 15% ASA added had the best performance.

Lignin/polyaniline composites were prepared by adding kraft lignin for the synthesis of polyaniline (PANI), a typical conductive polymer. The composites were utilized as an adsorbent for the removal of hexavalent chromium (Cr(VI)). When lignin alone was used as an adsorbent, the removal efficiency of Cr was low. However, when the lignin/PANI composite was used, lignin and PANI adsorbed Cr(III) together. The PANI reduced Cr(VI), which resulted in the efficient removal of Cr. In addition, as the dosage of the lignin/PANI composite decreased as an adsorbent, the Cr removal efficiency of the composite decreased considerably compared with pure PANI. However, the composite with a lignin-to-PANI ratio of 1:1 showed a Cr removal efficiency similar to that of pure PANI. The morphology of the lignin/PANI composite was observed to synthesize PANI around the lignin surface. Both Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that an interaction between the carbonyl groups of lignin and the amine groups of PANI occurred. This study is expected to provide an opportunity to increase the utilization of lignin in the field of environmental science and provide several benefits.

Soybean-oil rosin-based polyester (SRP) has many uses in papermaking, but its performance as an internal sizing agent differs depending on the circumstances. In this study, a comprehensive laboratory approach was used to investigate the process variables affecting SRP application. Five levels of SRP (0.5%, 1.0%, 1.5%, 2.0%, and 2.5%), five levels of aluminum sulfate (0.5%, 1.0%, 1.5%, 2.0%, and 2.5%), and five levels of cationic polyacrylamide (0.05%, 0.1%, 0.15%, 0.2%, and 0.25%) were considered to determine the best process variables within a pH range of 5.0 to 9.0. Aspects that were considered included the mechanical properties (tensile, burst, and tear indices), water resistance (Cobb test, dynamic c9197ontact angle test, and scanning electron microscopy), and chemical usage (economical and environmentally friendly procedures). The optimum conditions based on these factors were 1.0% SRP, 1.0% aluminum sulfate, and 0.15% cationic polyacrylamide levels at a pH of 7.0. The results showed that in the optimal sizing system, 15% calcium carbonate can be tolerated.

The potential of organic and inorganic fillers at different loadings (ranging from 1% to 10%) was evaluated as a means to enhance the performance of Kappaphycus spp.-derived biopolymer films. The morphological properties of organic and inorganic fillers were characterized by scanning electron microscopy (SEM). The organic fillers displayed an irregular rod shape with sizes from 60 µm to 80 µm, while the inorganic fillers displayed spherical shapes with a much smaller size range (0.08 µm to 0.25 µm). The contact angle (CA) and mechanical properties of the fabricated biopolymer films were remarkably enhanced compared to the neat biopolymer films due to the incorporation of organic and inorganic fillers. The highest tensile strength (TS), CA, and water barrier properties were attained by biopolymer films that incorporated 5% organic and 1% inorganic fillers. Up to now, there has been no such report on the role of organic and inorganic fillers on tuning the performance of the Kappaphycus spp.-based biopolymer films. This work demonstrated that the biopolymer films containing inorganic fillers promoted better physical-mechanical performance compared to the biopolymer films with organic fillers, achieving desirable properties for various packaging applications.

The wood dowel pin is one of the common fasteners for connecting structural members in wooden furniture frame construction, such as chairs. The effects of dowel penetration depth, shear strengths of connection member and dowel materials, dowel surface texture, and member grain orientation on ultimate direct withdrawal loads of single dowels withdrawn from wooden materials were investigated. The main findings were that the connections using dowels and main members with low shear strength properties achieved the same ultimate direct withdrawal loads with connections using the materials with higher shear strength properties for dowels and main members. Additionally, the existing empirical equations, including shear strength properties for both dowel and main member materials used to construct dowel connections, tended to remarkably underestimate the ultimate direct withdrawal loads of the evaluated dowel connections withdrawn from the end and side grains of the tested wood species. The connection main members in this study when these two shear strength values were added together was less than 25 MPa. Both estimation expressions were modified to consider the lower shear strength effort on ultimate direct withdrawal loads of dowels evaluated in this experiment.