• Journal of the Korea Furniture Society
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• v.14 no.2
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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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• v.39 no.5
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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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• v.49 no.4
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• pp.360-370
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• 2021

For the purpose of finding new uses for Miscanthus sinensis var. purpurascens, this study first constructed boards with the particles of the plant and impregnated them with phenolic resin at resin impregnation rates of 30 ± 2%, 40 ± 2%, 50 ± 2%, and 60 ± 2%. The impregnated boards were then carbonized at the carbonization temperature of 800℃, after which their density and mechanical properties were examined according to the different resin impregnation rates. The results showed that density, flexural strength performance, Brinell hardness, and compressive strength increased as the resin impregnation rate increased, thus affecting the physical and mechanical properties of the ceramics made of M. sinensis var. purpurascens particles.

• Journal of the Korean Wood Science and Technology
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• v.41 no.2
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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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• s.18
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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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• v.38 no.3
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• pp.178-184
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• 2010

This study was carried out to investigate the properties of woodceramics made from woody part of Broussonetia Kazinoki at different impregnation ratios of phenolic resin of 40, 50, 60, 70%. The physical and mechanical properties increased with increasing impregnation ratio. The highest mean values of density, bending strength, Brinell hardness and compressive strength were 0.66 g/$cm^3$, 53 kgf/$cm^2$, 187 kgf/$cm^2$, 126 kgf/$cm^2$, respectively. There were close correlations between density and bending strength, Brinell hardness and compressive strength, and between MOE and MOR.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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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.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.5
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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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• v.15 no.2
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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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• v.44 no.1
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• pp.106-112
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• 2016

This study investigated electrical properties and far-infrared ray emission according to the carbonizing temperature and phenol-formaldehyde (PF) resin impregnation ratio of ceramics manufactured using sawdust and rice husk. The far-infrared ray emission values and emission energy values decreased as the carbonizing temperature increased. The far-infrared ray emission values of the ceramics manufactured using a carbonizing process at $600^{\circ}C$ and a board with a PF resin impregnation ratio of 60 percent was 0.930; the emission energy presented the highest value of $4.32{\times}10w/m^2$. The electric resistance decreased as the carbonizing temperature increased. For the increase in the carbonizing temperature above $1200^{\circ}C$, ceramics was very close to a conductor due to the small resistance. The power consumption increased by the decrease of electric resistance and increase of the electric current in the case of a higher resin impregnation ratio.