• 한국가구학회지
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• 제14권2호
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• pp.21-29
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• 2003

This study was carried out to investigate characteristics of plywood overlaid with softwood veneers densified by resin impregnation and compression. The resin impregnability of Korean pine veneer under atmospheric pressure soaking was greater than that of larch, and impregnability of melamine resin was slightly greater than phenolic resin. It was suggested that resin impregnation ratio was affected by density and thickness of veneer. The largest melamine resin impregnation ratio of 50.7% was obtained with 1.26mm thick Korean pine veneer, and the lowest phenolic resin impregnation ratio of 11.7% with 3.41mm thick larch veneer. Therefore, it was suggested that the vacuum-pres sure-soak treatment is required at thick larch veneer. In densifying resin-impregnated veneers, densification ratio from 13.4 to 31.2% was obtained by high pressure from 15.6 to $20.8kgf/cm^2$. Impregnation of melamine resin also showed relatively greater at densification than that of phenolic resin. So it showed the degree of densification of about 20% or greater. It was seemed that adhesive bonding strength of plywood(base panel) which was directly pressed and overlaid with resin-impregnated veneer was affected by resin tackiness after resin impregnation followed by semi-drying. In laboratory scale, melamine resin impregnation was more favorable for the development of adhesive bonding strength owing to moisture control.

• Journal of the Korean Wood Science and Technology
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• 제39권5호
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• pp.398-405
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• 2011

Nondestructive evaluation (NDE) technique method using a resonance frequency mode was carried out for woodceramics made by different phenol resin impregnation ratios (40, 50, 60, 70%) for Broussonetia Kazinoki Sieb. Dynamic modulus of elasticity increased with increasing resin impregnation ratios. There was a close relationship between dynamic modulus of elasticity and static bending modulus of elasticity and between dynamic modulus of elasticity and MOR and between static bending modulus of elasticity and MOR. Therefore, the dynamic modulus of elasticity using resonance frequency mode is useful as a nondestructive evaluation method for predicting the MOR of woodceramics made by different impregnation ratios.

• Journal of the Korean Wood Science and Technology
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• 제49권4호
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• pp.360-370
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• 2021

본 연구는 거대억새의 활용방안을 찾기 위하여 거대억새 파티클로 보드를 제조한 다음 페놀수지를 함침한 후 수지함침 율이 30 ± 2%, 40 ± 2%, 50 ± 2%, 60 ± 2% 인 함침보드를 탄화온도 800℃로 탄화하여 수지함침율에 따라 밀도 및 역학적 성질을 조사하였다. 밀도, 휨강도성능, Brinell경도 및 압축강도는 수지함침율이 증가 할수록 증가하여 거대억새 파티클로 제조된 세라믹의 물리 및 역학적 성질에 영향을 주었다.

• Journal of the Korean Wood Science and Technology
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• 제41권2호
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• pp.105-110
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• 2013

A repeated impregnation and carbonization process was performed to prepare high-density woodceramics using MDF. The physical properties were estimated to further confirm morphologically structurally occurred changes of one-time and two-time phenolic resin treated and carbonized woodceramics. As compare one-time and two-time carbonized woodceramics, the increasing rate of weight and density declined after second carbonization as the resin impregnation ratio grew higher, and when the resin impregnation ratio was 40 percent, the weight and density of the second carbonization increased more than in the first step by 20.5% and 33.9% respectively which were the highest rates.

• 한국기계연구소 소보
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• 통권18호
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• pp.163-168
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• 1988

Impregnation of molten thermoplastic resin into continuous unidirectional fiber bundles was investigated. The degree of impregnation is defined as the ratio between the number of impregnated fibers and the total number of fibers of a bundle. The degree of impregnation was modeled as a function of time, impregnation pressure, temperature and tow size assuming the radial inward flow through the fiber bundle is governed by the Darcy's law. The permeability was assumed to be constant. Experiments were performed to evaluate the validity of the medel. Today's T300 graphite fiber bundles and Polyetheretherketone(PEEK) resin was used. A fiber bundle and resin powder were put into a mold and pressure and temperature were applied. After a predetermined time, the sample was taken out and microphotographs of the cross-section were taken. From the microphotographs, the number of impregnated fibers was counted and then the degree of impregnation was determined. Experiments were also performed for different tow sizes. Good agreements were found between the model and the experiments rendering a confidence in the model.

• Journal of the Korean Wood Science and Technology
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• 제38권3호
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• pp.178-184
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• 2010

인피섬유로 한지를 제조하고 남은 닥나무 목질부를 고부가가치화 하기 위하여 닥나무 목질부로 파티클 보드를 제조하고 페놀수지 함침율 변화에 따른 닥나무재료 우드세라믹을 제조하여 물성을 검토하였다. 밀도, 휨강도성능, Brinell 경도, 압축강도 등은 수지함침량이 증가할수록 증가하였으며 밀도와 휨강도성능, 경도, 압축강도간 및 휨탄성계수와 강도간에는 유의성이 인정되는 밀접한 상관관계를 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제42권2호
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• pp.130-137
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• 2014

Nondestructive evaluation (NDE) method by using a resonance frequency mode was carried out for ceramics made from particle boards with different phenol resin impregnation ratios (30, 40, 50, 60%) at carbonizing temperature of $800^{\circ}C$. The material for ceramics was Miscanthus sinensis var. purpurascens board. Dynamic modulus of elasticity increased with increasing impregnation ratio. There was a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to modulus of rupture (MOR). However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by free vibration mode is more useful as a nondestructive evaluation method for predicting the MOR of ceramics made from Miscanthus sinensis var. purpurascens particle boards by different phenol resin impregnation ratios.

• 한국생산제조학회지
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• 제22권5호
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• pp.806-811
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• 2013

In this study, to prevent the nonhomogeneity of fiber orientation during the molding of GFRP composites, GFRP prepreg was fabricated using roving fiber and polypropylene resin. Analyses on the degree of impregnation, tensile strength, and microstructure were conducted on the fabricated prepregs. A lower pulling speed, higher resin temperature, and longer die length showed a greater degree of impregnation of the prepreg. The scanning electron microscope (SEM) micrograph showed, a homogeneous fiber orientation. As a result, fundamental techniques for improved productivity were suggested for the manufacturing field.

• Carbon letters
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• 제15권2호
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• pp.142-145
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• 2014

Isotropic synthetic graphite scrap and phenolic resin were mixed, and the mixed powder was formed at 300 MPa to produce a green body. New bulk graphite was produced by carbonizing the green body at $700^{\circ}C$, and the bulk graphite thus produced was impregnated with resin and re-carbonized at $700^{\circ}C$. The bulk density of the bulk graphite was $1.29g/cm^3$, and the porosity of the open pores was 29.8%. After one impregnation, the density increased to $1.44g/cm^3$ while the porosity decreased to 25.2%. Differences in the pore distribution before and after impregnation were easily confirmed by observing the microstructure. In addition, by using an X-ray diffractometer, the degrees-of-alignment (Da) were obtained for one side perpendicular to the direction of compression molding of the bulk graphite (the "top-face"), and one side parallel to the direction of compression molding (the "side-face"). The anisotropy ratio calculated from the Da-values obtained was 1.13, which indicates comparatively good isotropy.

• Journal of the Korean Wood Science and Technology
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• 제44권1호
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• pp.106-112
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• 2016

농림 부산물인 톱밥과 왕겨를 이용하여 세라믹을 제조하고 페놀수지 함침율과 탄화 온도에 따른 전기적 성질 및 원적외선 방사특성을 조사하였다. 원적외선 방사율과 방사 에너지 값은 탄화온도가 증가함에 따라 감소하였으며, 수지함침율 60%, 탄화온도 $600^{\circ}C$일 때 원적외선 방사율은 0.930, 방사에너지는 $4.32{\times}10w/m^2$로 가장 높았다. 전기저항 값은 탄화온도가 증가함에 띠라 감소하여 $1200^{\circ}C$ 이상에서는 거의 도체에 가까운 성질을 보였다. 소비전력은 수지함침율이 높을수록 전기저항의 감소와 전류의 증가로 함께 증가하였다.