• Journal of the Korea Furniture Society
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• v.12 no.2
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• pp.1-10
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• 2001

As finger joint method has a high rate of yield and high strength and ease in working, it has been widely used as an end joint method for solid wood and wood based-material. Therefore, we end-joined the material of Pinus densiflora, Quercus variabilis and populus euramericana with polyvinyl acetate adhesive and resorcinol phenol resin adhesive. The effect of difference (0, 0.15, 0.3, 0.45mm) between the dimensions of tip width and root width of the finger (DTRW) on bending strength properties was as follows: 1. In the case of polyvinyl acetate adhesive, DTRW had no effect on bending modulus of elasticity(MOE) and modulus of rupture(MOR) of the three kinds of species, because their bonding layers were destroyed by slippage, not their woody parts. 2. In the case of resorcinol phenol resin adhesive, the material of Quercus variabilis showed an optimal result at 0.15 or 0.3 of DTRW, while the poplar did at 0 of DTRW 3. The differences in efficiency ratio of bending MOR of populus euramericana, Pinus densiflora and Quercus variabilis species according to the kind of adhesive were 13-29%, 23-30% and 45-53%, respectively.

• Journal of the Korea Furniture Society
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• v.27 no.4
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• pp.302-308
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• 2016

It has been known that acetylation improves the dimensional stability of wood. Liquid phase acetylation is more popular than gas-phase acetylation for the effectiveness of weight gain of wood. In this study the specimens of domestic red and Korean pines are acetylated in liquid phase and their physical properties, such as density, bending strength, anti-hygroscopicity etc., are analyzed. Acetylation increases the average weights and volume of larch specimens by 11.4% and 3.4%, respectively, and their average oven-dry densities are increased by $0.03g/cm^3$. Acetylation does not influence on Modulus of Rupture (MOR) and Modulus of Elasticity (MOE). The average Percentage Reduction in Hygroscopicity (PRH) and average Percentage Reduction in Water soaking (PRW) of larch specimens are respectively 20.2% and 20.8%. Thus it can be concluded that acetylation improves the dimensional stability of larch specimens.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.538-547
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• 2011

In this study, eco-friendly hybrid composite boards were manufactured from green tea and wood fibers for application as interior materials with various functionalities of green tea and strong strength properties of wood fibers. In this relation, the effect of green tea content on dynamic MOEs (modulus of elasticity) of these green tea and wood fibers composite boards were investigated. The dynamic MOEs of hybrid composite boards were lower than those of control boards without green tea, and the values decreased with the increase of green tea content. Also, the dynamic MOEs appeared to be somewhat different by resin type used for board manufacture. The hybrid composite boards manufactured from $E_1$ grade urea resin, which has higher molar ratio of formaldehyde to urea than that of $E_0$ grade one, were 1.06~1.54 times higher than that manufactured from $E_0$ grade. And, the differences between hybrid composite boards manufactured from both adhesive increased with the increase of green tea content. On the other hand, high correlations were found between dynamic MOE and static bending strength performances, it was concluded that static bending strength performances could be estimated from the dynamic MOE, except for a few hybrid board types with large variations.

• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.546-555
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• 2009

To study an effective use of woods, three-ply hybrid laminated woods instead of crosslaminated woods which are composed of spruce in the face and three kinds of wood-based boards (MDF, PB, OSB) in the core were manufactured, and the effect of constitution elements for the core laminae on bending strength performances was investigated. Bending modulus of elasticity (MOE) of hybrid laminated woods had the highest values for the hybrid laminated wood types arranging OSB laminae in the core, and had the lowest values for those arranging MDF laminae in the core. These values were higher than those of various cross-laminated woods. The estimated bending MOEs of the hybrid laminated woods which were composed of perpendicular-direction lamina of spruce in the faces were similar to their measured values, regardless of wood-based boards in the core. However, those of the hybrid laminated woods which were composed of parallel-direction lamina of spruce in the faces had much higher values than those of their measured values, and it was necessary to revise the measured values. Bending modulus of rupture (MOR) of the hybird laminated woods had the highest value for those arranging OSB laminae in the core, and had the lowest values for those arranging PB laminae in the core unlike the bending MOE. By hybrid laminating, the anisotropy of bending strength performances was markedly decreased, and the differences of strength performances among wood-based boards were also considerably decreased.

• Journal of the Korean Wood Science and Technology
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• v.52 no.2
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• pp.157-174
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• 2024

This study investigates the influence of varying concentrations of boric acid (BA) preservative on the physical and mechanical properties of light red meranti (LRM) found in Sarawak. LRM or Shorea leprosula samples were treated with various concentrations of BA via the dip diffusion method using American Society for Testing and Materials (ASTM) standards. The physical property, particularly the retention rate and mechanical properties, bending strength, modulus of elasticity (MOE), tensile and compression strength parallel to grain of impregnated and control samples were tested to determine the effects of BA preservative. The retention rate was found to increase with increasing BA concentration and higher surface area to volume ratio. The mechanical properties in terms of the MOE and tensile strength parallel to grain were found to be greater than those of the control samples, whereas the bending strength and tensile strength parallel to grain were lower. Amongst the results, only the retention rate and MOE showed significant interaction effects at 5% level of significance between all factors tested (samples size and BA concentration for retention rate and BA concentration for MOE).

• Journal of agriculture & life science
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• v.45 no.6
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• pp.41-46
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• 2011

In this study, in addition to the green tea-wood fiber hybrid composite boards of previous researches, to make effective use of saw dust of domestic cypress tree with functionalities and application as interior materials, eco-friendly hybrid composite boards were manufactured from wood fiber, green tea and saw dust of cypress tree. We investigated the effect of the component ratio of saw dust and green tea on static bending strength performances. Static bending MOE (modulus of elasticity) was within 0.956~1.18GPa, and showed the highest value in wood fiber : green tea : saw dust = 50 : 40 : 10 of the component ratio, and had the lowest value in 50 : 30 : 20 of component ratio. These values were 2.0~3.1times lower than those of green tea-wood fiber hybrid composite boards reported in the previous researches. The bending MOR (modulus of rupture) showed 8.99~11.5MPa, the change of the bending MOR with component ratio of the factors was the same as that of bending MOE. These values had 1.9~3.5 times lower value than those of green tea-wood fiber hybrid composite boards, and showed the slightly lower values than the MOR of particle boards (PB) and medium density fiberboards (MDF) prescribed in Korean Industrial Standard. Therefore, it is considered that these hybrid composite boards need to improve strength performances by component ratio change, hybrid composite with other materials and adhesive change etc. in order to industrialize the hybrid composite boards.

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.726-734
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• 2018

In this study, for using effectively domestic (temperate) small and medium diameter logs as a wooden floorboard, cross-laminated wood panels were manufactured using domestic larch and tulip woods as a base material for teak and merbau wood flooring, and static bending strength performances were measured to investigate the applicability as the base materials of wooden flooring in place of plywood. Static bending MOE was much influenced by the strength performances of the top layer lamina than that of the laminae for base materials. Bending MOR showed the higher values in tulip wood that was hardwoods than in larch wood that was softwoods regardless of the strength performances of the top layer laminae, and it was found that the values were much influenced by the strength performances of the base materials used in the core and bottom layers. However these values were 1.4-2.5 times higher values than the bending strength of the wooden floorboards specified in KS, it was found that it can be sufficiently applied to the base materials of wooden floorboards in place of plywood.

• Journal of agriculture & life science
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• v.46 no.2
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• pp.9-17
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• 2012

In this study, in addition to the green tea - wood fiber hybrid composite boards of previous researches, to make effective use of saw dust of domestic cypress tree with functionalities and application as interior materials, eco-friendly hybrid composite boards were manufactured from wood fiber, green tea and saw dust of cypress tree. We investigated the effect of the component ratio of saw dust and green tea on dynamic MOE (modulus of elasticity). Dynamic MOE was within 1.41~1.65 GPa, and showed the highest value in wood fiber : green tea : saw dust = 50 : 40 : 10 of the component ratio, and had the lowest value in 50 : 30 : 20 of component ratio. These values were 1.4~1.6 times higher than static bending MOE of wood fiber - saw dust - green tea hybrid composite boards, and were 2.0~2.9 times lower than those of green tea - wood fiber hybrid composite boards reported in the previous researches. From the results of correlation regression analyses between dynamic MOE and static strength performances, a very high correlation coefficients were obtained, therefore it was found that static bending strength performances can be estimated with a high reliability from dynamic MOE.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.95-101
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• 2002

Physical and mechanical properties of major Korean ash species were examined. For Fraxinus rhynchophylla and Fraxinus sieboldiana, green moisture content of sapwood was almost the same value as heartwood. Heartwood of Fraxinus mandshurica, however, had slightly higher moisture content than sapwood. Green and oven dry densities of F. mandshurica were lower than those of F. rhynchophylla and F. sieboldiana. Swelling and shrinkage of sapwood in F. sieboldiana showed somewhat higher value than those of F. rhynchophylla. Longitudinal compressive strength and modulus of elasticity in F. sieboldiana were lower values than those in the other species. Shearing strength in radial section was higher than that in tangential section of all samples. It could be noted that shearing strength of F. sieboldiana demonstrated higher value than that of the other species. Three species had excellent bending properties in MOR and MOE. Impact bending absorbed energy for F. rhynchophylla and F. mandshurica did not show any significant differences.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.429-437
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• 2015

It has been known that acetylation improves the dimensional stability of wood. Liquid phase acetylation is more popular than gas-phase acetylation for the effectiveness of weight gain of wood. In this study domestic red and Korean pine specimens were liquid phase acetylated and their physical properties, such as density, bending strength, dimensional stability etc., were investigated. Acetylation increased the average weights of red and Korean pine specimens by 10.4% and 9.2%, respectively, and their average oven-dry densities were increased by 6.9% and 4.6%, respectively. Acetylation did not influence on modulus of rupture (MOR), modulus of elasticity (MOE) and dynamic MOE (DMOE). The average percentage reduction in hygroscopicity (PRH) of red and Korean pine specimens were respectively 20.6% and 13.8%, while the average percentage reduction in water soaking (PRW) were respectively 20.0% and 8.5%. Thus it can be concluded that the liquid acetylation improved the dimensional stability of red pine specimens more than that of Korean pine specimens.