The demand for wood-based materials as an alternative to plywood is increasing, and a synthetic adhesive is typically used for the fabrication of such materials. The identification of replacements for standard adhesives poses a major challenge. In this study, we investigated the mechanical properties of particleboard bonded by cellulose nanofiber (CNF) and compared the mechanical properties of particleboard bonded by CNF with those of particleboard bonded by adhesive. CNF was added together with wood particles during the fabrication process. The target CNF addition amounts were 0, 3, 5, 10, and 20 weight percent. The bending and internal bond strengths of the particleboard with CNF increased, and its water absorption decreased as CNF content increased. The comparison between the boards prepared with adhesives and those with CNF showed that the properties of boards prepared with 20 weight percent CNF were comparable to those of boards prepared with 1 weight percent synthetic adhesive.Abstract
The purpose of this paper is to discuss the influence of different proportions of bamboo pulp residue on the bending strength, the static bending strength, the water absorption rate, and the microstructure of wood flour/phenolic resin composites. The level of bamboo pulp residue ranged from 0 to 30 percent. According to the optimum technological parameters of the pretest, the resin content, the molding temperature, and the molding time were controlled within 51 to 54 percent, 152°C to 160°C, and 51 to 60 s/mm, respectively. Compared with the control group, there were remarkable improvements in the mechanical properties, indicating that the bending strength, the static bending strength, and the water absorption rate increased by 39, 31, and −6 percent, respectively. The greatest level of bamboo pulp residue was 20, 20, and 10 percent for the bending strength, the static bending strength, and the water absorption rate, respectively. All of the above proved that the wood flour/phenolic resin composites can be modified by adding bamboo pulp residue.Abstract
The objective of this research was to analyze the reinforcement effect of microfibrillated cellulose (MFC) on chitosan–polyvinyl alcohol (chitosan-PVA) nanocomposite films in terms of their morphological, physical, chemical, thermal, biological, and mechanical properties. Chitosan-PVA blend films reinforced with MFC filler loadings at 0.5 to 5 percent had smoother, more regular, and more uniform external surface morphology compared with chitosan-PVA reinforced with MFC filler loaded at 7.5 percent. With regard to the physical properties, incorporation of MFC into chitosan-PVA polymer blends reduced nanocomposite film transparency. Furthermore, the films had three different diffraction peaks: crystalline peak, amorphous peak, and small ancillary peak. Compared with the neat chitosan-PVA blend, the addition of MFC to chitosan-PVA polymer blends shifted Fourier-transform infrared spectroscopy peaks at 3,500 to 3,000, 2,918, 1,440, 1,101, and 850 cm−1, indicating a chemical interaction between chitosan-PVA polymer blends and MFC. According to differential scanning calorimetry, thermogravimetric analysis, and differential thermal analysis, the addition of MFC enhanced the thermal stability of chitosan-PVA compared with neat chitosan-PVA composite films. Most nanocomposite films reinforced with MFC had a higher tensile strength than films made from neat chitosan-PVA and chitosan-PVA-MFC 7.5 percent because of percolation formation. However, neither neat chitosan-PVA composite film nor chitosan-PVA-MFC nanocomposite films showed a zone of inhibition or had a zone of inhibition index against Escherichia coli, Staphylococcus aureus, Candida albicans, and Ganoderma sp.Abstract
A three-step carbamylation reaction of diethylene triamine (DA) with urea was investigated to find an efficient synthesis procedure for large-scale production of diethylene tricarbamide (D), a monomer of D-formaldehyde resin binders for wood composite boards with very low formaldehyde emission potential. n-Butanol, pyridine, and others with minor amounts of polar solvents were investigated as a reaction medium. Urea is added to the solvent in a stirred reactor and heated to the boiling point of the solvent, which is about 110°C to 130°C. This was followed by the gradual addition of DA while allowing evolved ammonia to escape through the condenser. A delicate balance exists between voluminous particles of di-substituted intermediates and the hard fine particles of tri-substituted final product, and an excessive buildup of the former often occurs, resulting in stirring difficulties, reaction stoppage, and low reaction yields, which are minimized by adding some polar solvents and also by programmed addition of DA. Free-flowing microcrystalline particles of D were obtained in yields of 90 to 98 percent based on DA in 6 to 12 hours of reaction by simple filtration, hot washing with solvents, and drying procedures. These organic solvent–based synthesis procedures appear possible to adapt to large-scale production of D. The ammonia that evolves from the reaction needs to be captured, and solvent losses should be minimized. The high current price of DA, the need to reuse ammonia, and the complexity of the reaction indicate that a company that manufactures ammonia, urea, and DA fit to adopt this technology in support of the wood composite board industry.Abstract
Diethylene tricarbamide–formaldehyde (DF) resins were investigated for syntheses at low mole ratios and at about 60 percent resin solids levels in water as low formaldehyde-emitting binders of wood composite boards. Tri-functional monomer D was shown to react readily with formaldehyde to form hydroxymethyl groups that then react to form methylene bonds between molecules to form DF resins of water-soluble oligomeric condensation products, similar to urea-formaldehyde (UF) resins. DF resins showed a better storage life and longer pot life than, and similar cure times as, UF resins. DF resins also bonded laboratory particleboard as effectively as UF resins in terms of hot-pressing parameters and resultant boards' physical properties, while the formaldehyde content (FC) values of boards were lower by about 75 percent than UF resins, at about 2.3 to 4.4 mg/100 g wood by the Perforator method, significantly below the current regulation levels. Copolymer resins made with up to 15 percent urea substitutions performed equally well as particleboard binders with only slightly increased FC values, indicating some cost savings possible for industry. Copolymer resins made with up to 25 percent melamine also performed well with similarly low FC values and improved the physical properties of boards, indicating some lowering of loading levels of resin solids possible for industry, especially in the formulating of face layer resins. DF and copolymer resins are considered to be adaptable in current resin and board manufacturing plants to produce wood composite boards with a low formaldehyde emission potentials and without loss of productivity and board quality, a problem present in the current wood composites manufacturing industries.Abstract
Phenol-tannin-formaldehyde (PTF) resins were prepared by adding bark tannin extracts from mangium (Acacia mangium) to phenol-formaldehyde (PF) resin adhesive. The resultant resin was used for bonding wood from three fast-growing tropical species, specifically, mangium, jabon (Anthocephalus cadamba), and mindi (Melia azedarach). The impact of the tannin extract content on the penetration and adhesion strength of PTF resin adhesives was studied for two different tannin contents (10% and 20%). The resin penetration into wood tissues of the three species was quantitatively measured at the bond line, using a light microscope. Confocal laser scanning microscopy was also used for detecting the resin penetration into wood tissues. The adhesion strength of the PTF resins was determined by measuring shear strength of three-ply parallel plywood constructed from the three tropical woods. As the amount of tannin increased, the depth of resin penetration increased for mangium and jabon wood but decreased for mindi wood. By contrast, the bond-line thickness decreased with the increasing tannin addition for all three wood species. The adhesion strength of plywood was improved as the amount of tannin increased. All plywood bonded with PTF resins using 20 percent tannin met the requirements of the EN 314‐2 standard. These results suggest that the addition of tannin extract into PF resin improves the adhesion performance and can partially replace phenol in PTF resins.Abstract
This study determined the effects of surface veneering (V), edge banding (E), and handle and hinge holing on formaldehyde emission (FE) for standard particleboard (PB) and medium-density fiberboard (MDF). Thirty test samples were prepared from PB and MDF. Each sample was pressed by 0.6-mm beech veneer and edged with 2-mm beech veneers. In the samples, two handle holes were drilled with 18-mm depth and 5-mm diameter, and two hinge holes were drilled with 15-mm depth and 30-mm diameter. FE was measured in accordance with Turkish standards by a MultiRAE multiple gas analyzer. A significant decrease from 93 to 80 percent for PBs and from 72 to 22 percent for MDFs was detected when compared with the control samples. V and E of boards (PB/MDF + V + E) significantly reduced FE from 1.1078 to 0.0733 parts per million (ppm) (93%) for PB and from 0.2311 to 0.0667 ppm (72%) for MDF. Drilling holes for hinges and handles (H) on the surfaces of boards slightly increased FE from 0.0733 to 0.0789 ppm for PB and from 0.0644 to 0.0789 ppm for MDF. Regarding distance to E1 (0.10 ppm), unprocessed control samples and samples of PB + V and MDF + V yielded results higher than the limits of E1. In conclusion, V and E significantly reduced FE, whereas H slightly increased FE. The need for a way to reduce FE to accepted levels is of great concern for the Turkish furniture industry.Abstract
It is well known that the release of volatile organic compounds (VOCs) and odors from wood-based panels is harmful to human health. The VOCs emitted from decorative wood-based panels have been investigated generally, but information is limited regarding the key odor compounds that people find most irritating. In this experiment, particleboard coated with nitrocellulose lacquer was analyzed by gas chromatography coupled with mass spectrometry and olfactometry. Twenty odors were identified, which arose between 5 and 25 minutes. Most odorants from nitrocellulose lacquer–coated particleboard were aromatics, esters, and alcohols, whereas those from control (unvarnished) particleboard were aromatics, aldehydes, and esters. With an increasing ratio of air exchange rate to loading factor, the total VOCs concentration and the total value of odor intensity from nitrocellulose lacquer–coated particleboard declined. However, both increased as temperature and relative humidity rose. The fluctuation of total VOCs between different days tended to fluctuate more sharply when the temperature and relative humidity rose and when the ratio of air exchange rate to loading factor dropped. To accelerate the release of VOCs and odors and reduce their effects on humans, the optimum storing conditions for particleboard with a nitrocellulose lacquer after-production were 40°C, 60 percent relative humidity, and a 1.0-m3·h−1·m−2 ratio of air exchange rate to loading factor.Abstract
Chloropicrin remains one of the most effective fumigants for arresting internal decay in large timber structures, but it can be difficult to handle. The potential for encapsulating chloropicrin to improve application safety and control the release rate was investigated in Douglas-fir poles. A quick-release ampule resulted in chloropicrin levels that were similar to those found with a similar amount of liquid chloropicrin, whereas moderate- and slow-release ampules resulted in proportionally less chloropicrin in the wood over a 4-year period, but levels were still well above the protective threshold. The results suggest that encapsulated chloropicrin improved handling safety without reducing performance. Further monitoring is planned.Abstract
The light-frame building construction market is increasingly competitive. To maintain and grow its position in the market, the lumber industry needs to be improved and refined. The identification of the strength-reducing characteristics that affect modulus of elasticity (MOE) and modulus of rupture (MOR) are keys to improve the grading process of lumber. Herein, nondestructive techniques, visual evaluation, and mechanical testing were used to assess the structural properties of 1,044 samples of southern pine lumber. Linear regression models were constructed for 2 by 4 and 2 by 6 southern pine lumber using the static bending MOE and MOR, both as dependent variables from the destructive test. Nondestructive measurements, visual characteristics, and lumber density were used as independent variables. Linear regression models were constructed to indirectly estimate the MOE and MOR of southern pine lumber. The variables selected to predict MOE were dynamic modulus of elasticity (dMOE) and density. By adding knot diameter ratio to dMOE and density, it was possible to develop a prediction model for MOR. It was possible to improve predictability of strength (MOR) with a combination of nondestructive testing and knot evaluation.Abstract
To promote the structural use of small-diameter logs often harvested in Korea, the use of laminated members with square timber obtained from small-diameter logs as their elements is being considered. With the objective of improved strength, elements obtained from large-diameter logs were combined with elements obtained from small-diameter logs. In this study, the authors prepared beam-column joints using these laminated members and examined their moment resistance performance. To join a laminated beam and a laminated column, the authors used glued-in steel rods. The results of a mechanical test on the moment–deformation angle relationship showed that from the initial force to the failure point, the behavior was mostly linear. Moreover, the rotational stiffness was approximately 900 kNm/rad, the maximum moment was approximately 30 kNm, and the joint efficiency for deformation was approximately 0.8. It was revealed that a significant amount of the deformation in this specimen resulted from the bending deflection of the laminated column. The authors also estimated the rotational stiffness and maximum moment through linear analysis. The slip properties of the deformed bar, compression properties perpendicular to grain of the laminated column, and bending properties of the laminated column were taken into consideration. The estimated results were mostly consistent with the experimental results. As a method to easily understand the moment resistance performance of these joints, the present proposed estimation method should be effective.Abstract
To model international trade of forest products we use a gravity model of trade. In modeling trade, we estimate the impact of importer gross domestic product (GDP), exporter GDP, and distance between trading partners using Poisson pseudo-maximum likelihood (PPML). When estimating the log-linearized gravity model (ordinary least squares [OLS]), two issues arise. First, potential bias associated with truncation of all zero-trade observations due to the nonexistence of the natural log of zero. Second, heteroscedasticity can bias results from the log-linearized gravity model because of the multiplicative error term of the stochastic gravity model. To address these two issues, we propose avoiding the log-linearized gravity model and instead estimate the nonlinear gravity model via PPML. To estimate the model, trade data are compiled from the Food and Agriculture Organization of the United Nations. The observation window is from 1997 to 2014 and covers 13 product categories at a country-pair level. In our estimation, we find systematic differences in estimates from OLS in comparison with estimates from PPML. Using the estimated elasticities, in combination with estimates of future GDP from shared socioeconomic pathways, we project future US exports to the year 2030 for each item category in addition to total exports for Brazilian wood pulp, New Zealand industrial roundwood, and Canadian coniferous sawnwood. Using our approach, we provide a tool for policy makers and industry leaders alike to make informed decisions over prior estimates of forest product trade.Abstract
The sustained and rapid growth of China's economy has led to the improvement of Chinese living standards. This, in turn, has led to the adoption of the lifestyles of health and sustainability (LOHAS) by many Chinese middle-class consumers. In pursuit of a higher quality of life, these consumers have shown a growing interest in eco-friendly products, including eco-friendly children's furniture. Using a structured questionnaire distributed to a sample of 320 consumers in two Chinese metropolitan cities (Shanghai and Shenzhen) in 2013, this study examined consumer stated willingness-to-pay (WTP) a price premium for eco-friendly children's furniture. Results indicate that 98 percent of respondents would be willing to pay a premium for such products. Of these respondents, 53 percent of them stated a WTP of no greater than 10 percent, while 45 percent of them stated a WTP of more than 10 percent. Results of an ordered probit model suggest significant correlations between respondent WTP and their marital status, education level, LOHAS orientation, and environmental perceptions. The findings of this study can serve as a useful reference for policy makers, furniture producers, and wood material suppliers that are currently planning to enter eco-friendly markets where price premiums might exist.Abstract
This paper analyzes the transformation of manufacturing in China's furnishings industry and the status of intelligent manufacturing on the basis of the industry status quo, corporate development around custom furnishings and digital manufacturing, and management and control of manufacturing information. On the basis of an understanding of smart homes, the guiding ideology and key technology in intelligent manufacturing in the furnishings industry involve digital manufacturing. This article comprehensively analyzes the influences of intelligent manufacturing on the furnishings industry related to diverse structure, sales, service, and competition among enterprises. We propose that the development direction of the intelligent manufacturing of furnishings includes digital transformation, collaborative platform construction, and continued improvements to distribution. This article also provides new ideas for the development and transformation of the personally customized furnishings industry and offers implications for digital manufacturing in the furnishings industry in the future.Abstract