• 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.

• 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.43 no.3
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• pp.327-333
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• 2015

To measure the dimensional stability of three softwoods by vacuum pressurization of water soluble melamine-formaldehyde (MF) resin impregnation process, properties of resin treated compressed woods (compregs) were measured after impregnating the water soluble MF resin into three coniferous wood species for different impregnation times and resin concentrations. As the resin concentration was higher and impregnation time was longer, coefficients of volumetric shrinkage and anti-volumetric swelling efficiency increased, but coefficients of volumetric swelling, anti-volumetric swelling efficiency and absorption decreased. Also, weight percent gain increased remarkably as the resin concentration was high, but there was no uniform relationship with impregnation time.

• Journal of the Korean Wood Science and Technology
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• v.32 no.3
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• pp.25-32
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• 2004

This research work explored physical and mechanical properties of impregnated sawdust boards from three softwood species (P, densifora, L. kaemferi, and P. koraiensis) with phenol-formaldehyde (PF) resin by various vacuum treatment methods of combining pressure, vacuum, and ultrasonic waves. Simultaneous vacuum and ultrasonic wave treatments with no pressure resulted in the greatest increase in resin content, density, dimensional changes (thickness and length), bending strength, and hardness of impregnated board. This result seemed to be attributed to the ultrasonic wave treatment.

• 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.31 no.5
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• pp.15-22
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• 2003

This study was carried out to investigate the properties of sawdust board impregnated with phenol resin according to the density and resin content of board. The sawdust board were manufactured to target densities of 0.4, 0.5, 0.6, 0.7 g/cm³ and resin content of 5, 10, 15, 20% made from Pinus densiflora S. et Z., Larix. kaemferi C. and Pinus koraiensis S. et Z. The impregnation process were executed in two ways, the application of vacuum pressure then followed by atmospheric pressure, and the application of vacuum pressure with ultrasonic vibration then followed by atmospheric pressure. The density of impregnated sawdust board increased as density and resin content of sawdust board increased, but impregnation rate decreased. The density, impregnation rate, bending strength and brinell hardness of sawdust board in impregnated vacuum pressure with ultrasonic vibration then nonpressure were higher than those of vacuum pressure then nonpressure. In this results, the impregnation rate is increased in vacuum pressure with ultrasonic vibration then nonpressure, it has affected the properties of sawdust board impregnated with phenol resin.

• Composites Research
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• v.36 no.6
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• pp.388-394
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• 2023

In composites manufacturing, increasing resin impregnation is a key way to speed up the manufacturing process and improve product quality. While resin improvement is important, simple fiber surface treatments can also improve resin flowability. In this study, different plasma treatment times were applied to carbon fiber fabrics to improve the impregnation between resin and fiber. Electrical resistivity measurements were used to evaluate the dispersion of resin in the fibers, which changed with plasma treatment. The effect of fiber surface treatment on resin spreadability could be observed in real time. When inserting a carbon fiber tow into the resin, the amount of resin that soaked into the tow was measured to objectively compare resin impregnation. Five minutes of plasma treatment improved the tensile and compressive strength of the composite by more than 50%, while reducing the void content and increasing the fire point impregnation flow rate. Finally, a dynamic flexural fatigue test was conducted using a portion of the composite used as an architectural composite part, and the composite part did not fail after one million cycles of a 3 kN load.

• Journal of the Korean Wood Science and Technology
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• v.33 no.3 s.131
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• pp.30-37
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• 2005

This study aimed at offering basic data to develop a new use of sawdust and rice husk. Research investigated the variation of density, weight loss and dimensional decreasing rate by the percentage of resin impregnation and carbonization temperature of ceramics, which were formed by the percentage of resin impregnation of 40~80% and carbonization of $600{\sim}1200^{\circ}C$ with board impregnated with phenolic resin made from sawdust and rice husk. The results of this study were as follows:1) As the percentage of resin impregnation increased, the thickness shrinkage and weight loss were decreased; on the other hand, density and modulus of rupture increased. Meanwhile, the carbonization temperature at $1200^{\circ}C$ showed the highest values, as the density was $0.81g/cm^3$ and the bending strength was $77.9kgf/cm^2$ in the percentage of resin impregnation at 70%. 2) As the carbonization temperature grew higher the linear shrinkage, thickness shrinkage and weight loss increased while the density increased until the carbonization temperature of $1000^{\circ}C$; but then decreased slightly at $1200^{\circ}C$.

• Journal of Korea Foresty Energy
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• v.22 no.1
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• pp.24-29
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• 2003

Using woodceramics made from sawdust board of Larix leptolepis thinning logs, change in surface temperature were investigated, by the rate of resin impregnation and burning temperature. As the surface temperature of silicon rubber heater was going up, that of woodceramics also increase rapidly. Woodceramics made from under the condition of the rate of resin impregnation 70-80% and burning temperature 800-$1000^{\circ}C$, were higher than that of surface temperature. Also, it was found that woodceramics maintained heat for a long time because the descending velocity of their surface temperature was lower than that of the heater.