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The objective of this study was to investigate the lab-scale manufacturing process of insulation fiberboard (1FB) with cellulose nanofibers (CNFs) and evaluate the effects of CNFs on the mechanical and physical properties of the IFB. Because the fabricated IFBs with CNFs had a homogeneous appearance, it was assumed that CNFs can be easily dispersed within IFB by adding them during the mixing stage of the wet process of wood-based board production. The results for the IFBs with CNFs revealed that the density and bending properties increased, while the thickness decreased with an increase in the CNF addition ratio. Furthermore, after the water absorption test, the weight change rates of the IFBs decreased, and the thickness swelling rates increased. Although the size of the specimens was different from the size in JIS A 5905 (Japan Standards Association 2014), the modulus of rupture (MOR) values of IFBs with a target density more than or equal to 0.20 g/[cm.sup.3] were higher than the value of A-class IFB in the standard for all CNF addition ratios. In addition, lower thermal conductivity may be realized under similar MOR values by adding CNFs to IFB. On the other hand, to produce CNF-reinforced IFBs with target density/thickness, it is necessary to develop a method for decreasing the cohesive force derived from CNF aggregation and the compressive force originating from the water surface tension caused by the high water retention of CNFs., Wood-based materials are used extensively in residential construction, particularly in Japan. These materials are made of virgin wood, recycled wood, unused wood species, or thinning wood. Many of the materials [...]

The addition of maleic anhydride (MA)-modified polypropylene (MAPP) as a compatibilizer increases mechanical and physical properties of wood/plastic composites (WPCs). It is thought that MA graft ratio (Gr), molecular weight (weight-average molecular weight [Mw]), and mixing methods of MAPP affect physical and mechanical properties of WPCs. However, evaluation, especially for mixing order, is not enough. The objective of this study was to investigate the effect of Gr and Mw of MAPP and its mixing methods on the mechanical and physical properties of WPCs. Two types of mixing methods were used: mixing the MAPP with the filler using a Henschel mixer before kneading with PP (premixing method) and mixing all of the materials at one time (one-step mixing method). The WPCs made with the premixing method had lower shear viscosity and higher flexural modulus than those made with the one-step mixing method. The particle size, moisture content, and surface morphology of fillers are thought to be more important in determining the shear viscosity of WPCs than the MAPP itself. The highest tensile, impact, and fiexural strengths of WPCs were obtained in the WPC with premixing with low-Gr and high-Mw MAPP. It may be due to the effective reaction of the wood flour with MAPP and higher entanglement between the MAPP and PP. These results suggest that the premixing method could improve productivity and mechanical properties of WPCs., Wood/plastic composites (WPCs) are produced from lignocellulose fillers, thermoplastic resin, and a small amount of additives. Lignocellulose fillers are biodegradable and carbon neutral (Kim and Pal 2010, Ndiaye and Tidjani [...]

Recently, the usage of wood--plastic composite (WPC) products has increased, mainly for exterior decking. The shape of fillers is one of the important factors deciding the mechanical and physical properties of WPCs. Surface-fibrillated wood flour (WF) improves the mechanical properties of WPCs, although it requires a lot of energy and time to produce the fibrous structure during the pulverization process. Therefore, the adsorptive interaction between cellulose nanofiber (CNF) and WF by hydrogen bonding was investigated. We considered that CNF could form the fibrous structures on the WF surface by mixing CNF and WF. Also, it is thought that the addition of CNF could increase mechanical and physical properties of WPC because CNF has better physical and mechanical properties than most other fibers. The objective of this study was to produce WF-CNF fillers and to evaluate the mechanical and physical properties of WPCs containing WF-CNF fillers. WF-CNF fillers could be produced by freeze-drying after mixing WF, CNF, and water. The fibrous structures on the WF surface were observed through scanning electron microscope images of WF-CNF filler containing 3 weight percent CNF. A WPC with WF-CNF filler containing 22 percent (by weight) WF and 3 percent (by weight) CNF showed improved mechanical properties compared with WPCs without CNF. The water absorption of WPCs containing CNF was found to decrease with increasing CNF content., Wood--plastic composite (WPC) is a material made by combining wood flour (WF), thermoplastic resin, and a small amount of additives. WPC can be produced from wood waste and recycled thermoplastic [...]

The objective of this research was to analyze the reinforcement effect of microfibrillated cellulose (MFC) on chitosanpolyvinyl 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. Furthemore, 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 chito.sanPVA polymer blends shifted Fourier-transform infrared spectroscopy peaks at 3,500 to 3,000, 2,918, 1,440, 1,101, and 850 [cm.sup.-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., Most composite films derived from petroleum-based polymers have recently come under scrutiny by scientists in the food and packaging industry worldwide due to the negative impact of these films on [...]

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 intemal 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., Wood-based materials are increasingly in demand, and their production is also increasing. For example, plywood is in high demand as a building material, while particleboard and medium-density fiberboard (MDF) are [...]

Relatively short-term (3-, 6-, and 12-mo) outdoor exposure tests using particleboard specimens of two different sizes to clarify the effect of specimen size and starting time on the deterioration of the mechanical properties (bending and internal bond strength) of the particleboard were conducted. The weathering intensity was determined from the results of the short-term exposure tests, and the effect of the specimen size on the weathering intensity was discussed. The strength retention tended to decrease exponentially with elapsed time. After a 1-year exposure in Shizuoka, Japan, the retained strength was less than 60 percent. Rectangular specimens had less strength retention than the square specimens and are thought to be a more reliable indicator of the true effect of weathering conditions on strength loss. Short- and long-term exposure tests are equally useful for determining the effect of outdoor exposure on particleboard properties., The use of wood-based panels, especially particleboard, in construction has been increasing steadily in Japan (Food and Agriculture Organization of the United Nations [FAO] 2016). Reduction in the domestic production [...]

Abstract Particleboard was fabricated using hinoki (Japanese cypress: Chamaecyparis obtsusa Endl.) particles and different amounts of diphenylmethane diisocyanate (MDI) resin (2%, 4%, 6%, and 9%) and phenol-formaldehyde (PF) resin (6% [...]

Durability of wood-based panels was evaluated by comparing thickness swelling (TS) results from five laboratory-accelerated aging tests with the TS results from panels that had experienced 2 years of outdoor exposure in Shizuoka City, Central Honshu, Japan. In each accelerated aging test, the total TS of phenol-formaldehyde (PF) resin bonded panels were higher than that of isocyanate resin diphenylmethane diisocyanate (MDI) bonded panels. The panels could be divided into two groups based on the results of non-linear least-squares regression analysis of the rates of increase in TS. The Shizuoka 2-year outdoor exposure test resulted in the TS of oriented strandboard (OSB) made from aspen exceeding 15 percent; TS of OSB made from pine and particleboard bonded with PF resin was about 10 percent. On the other hand, TS of the tested plywood and medium density fiberboard remained below 3 percent over the 2 years. Calculation of mean TS for all of the panels tested allowed comparison of the severity of aging between the accelerated test methods and outdoor exposure. Of the standard methods, the ASTM six-cycle test was the most severe, with the 2-year outdoor exposure proving no harsher than any of the accelerated aging procedures used., Performance durability is one of the most important properties of wood-based panels used in housing construction (McNatt and Link 1989, Kajita et al. 1991). Shortfalls in the domestic production of [...]

The use of wood thinnings from hinoki trees in the production of particleboard is important in Japan, as is the use of diphenylmethane diisocyanate (MDI) resin for mat-formed panels. MDI-bonded particleboard was fabricated to evaluate the effects of manufacturing parameters including board density (0.45 to 0.75 g/[cm.sup.3]), furnish type (hinoki, sugi, and commercial), and additives (control and wax sizing) on board performance. Exposure durability was evaluated by four accelerated aging treatments including two JIS methods, the V313 test, and the ASTM 6-cycle (6c) test method. A resin content of 6 percent with a density of 0.65 g/[cm.sup.3] produced a bending modulus of rupture of 40 MPa for hinoki board. The internal bond (IB) strength retention after JIS-A, JIS-B, and V313 treatments ranged from 85 to 90 percent. These results showed that MDI resin could produce high bond quality and durability performance. The mechanical properties of hinoki board were two to three times those of commercial particleboard. No effect with the addition of wax was found with respect to thickness swelling (TS) and IB strength after JIS treatments. But, the TS of the board without a wax addtive was approximately two times of that of the waxed board when subjected to ASTM-6c and V313 treatments., Thinnings cut from trees are estimated to total 5 million [m.sup.3] annually in Japan. Japanese cedar (sugi) and Japanese cypress (hinoki) account for the most common domestic coniferous thinnings. Hinoki, [...]