• Journal of the Korean Wood Science and Technology
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• v.27 no.4
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• pp.57-64
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• 1999

This research was carried out to investigate the effects of density, resin and particle types on the physical and mechanical properties of the composites made from various wood particles mixed with coating paper. The experiment was designed to apply with three particles (flake, chip, and fiber) and three resin types (urea, phenol and PMDI resin). The mixed ratio of coating paper to wood particle was fixed on 50 to 50% in each board making. And also it was designed to apply for four density levels (0.6, 0.7, 0.8 and 0.9 g/$cm^3$) and four mixed formulations of coating paper to wood particle (10:90, 20:80, 30:70, and 40:60 %) to analyze clearly the effects of PMDI resin. Coating paper-wood particle composites have acceptable bending strength (MOR, MOE) though the mixed ratio of coating paper was increased, but have low internal bond strength and poor dimensional stability (WA, TS, LE). Composites with high density had higher mechanical properties but showed lower physical properties than composites with low density. In conclusion, at least up to 20% mixed ratios, coating paper-wood particle composites have acceptable physical and mechanical properties, and PMDI resin has possibility for coating paper-wood particle composite manufacture.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.33-38
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• 1995

The rates of fixation of CCA-Type B and CCFZ in blocks of radiata pine sapwood were compared at various temperatures and conditioning methods (drying and nondrying conditioning). Also the time required to proper fixation of preservative components in the treated wood was estimated. Fixation was monitored by the rates of depletion of free hexavalent chromium in the cell lumens in the teated blocks. The rate of preservative fixation in wood was highly temperature dependent. The fixation rate was considerably accelerated by means of heating and complete fixation of hexavalent chromium was achieved within about 12 hours by heating at $60^{\circ}C$. The moisture content of treated wood during fixation apparently played an important role in the fixation process. The fixation rate of treated wood conditioned in nondrying conditions was much more faster than that of treated wood conditioned in drying conditions. particularly when the moisture content of treated wood was below fiber saturation point. Time required to full fixation could be predicted successfully using the fixation temperatures applied since the correlation between the fixation temperature and the fixation time was excellent. regardless of conditioning methods.

• Journal of the Korean Wood Science and Technology
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• v.45 no.4
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• pp.369-381
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• 2017

The objective of this study was to compare the wood anatomical characteristics of local tree species in Moluccas, Indonesia i.e., Moluccan ironwood (Intsia bijuga), linggua (Pterocarpus indicus), red meranti (Shorea parvifolia), and gofasa (Vitex cofassus). Qualitative evaluation was conducted by observing the anatomical structure in cross, radial, and tangential sections of each sample. For the quantitative evaluation, the dimensions of vessels, rays, and fibers were measured. Qualitative evaluation showed that crystals were observed in Moluccan ironwood, linggua, and gofasa, while resin canals were only observed in red meranti. Tyloses were frequently observed in gofasa but infrequently observed in linggua and red meranti. Quantitative evaluation showed that Moluccan ironwood with the higher density had thicker fiber wall, higher quantity of ray number, and wider rays than the other species. Red meranti had higher values of ray height and fiber length than the other three species. The results also revealed that linggua showed the highest values of relative crystallinity and crystallite width. Red meranti and gofasa showed similar values of relative crystallinity and crystallite width, while Moluccan ironwood showed the lowest values. The basic qualitative and quantitative anatomical characteristics discussed could provide useful information for further utilizations of such wood species.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.3
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• pp.49-59
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• 2009

The bast fibers of paper mulberry were dyed by using sappan wood, gardenia, and gallnut extracted under various extraction conditions. The surface absorption rates, color, and sunlight fastness of the dyed fibers were compared to those of the dyed cotton and silk. The K/S values of silk showed the highest values, followed by gallnut, gardenia, and sappan wood. The optimum extraction conditions of the dye materials were 20 g/L (input amount of dye materials per liter), $90^{\circ}C$ (extraction temperature), and 30 minutes (extraction time). The values of saturation were observed to increase with the increase of the amount of dye materials, extraction time, and extration temperature. However, no effect were found on the values of hue and lightness. In all samples, the developed colors dyed by sappan wood and gardenia were the series of YR, and Y, respectively. The colors of dyed cotton and bast fibers of paper mulberry by gallnut were the series of Y and the dyed silk showed the series of YR. The values of saturation of the bast fibers of paper mulberry by sappan wood and gardenia showed the highest values of saturation, followed by cotton, and silk. In the case of gallnut, cotton showed the highest values of saturation, followed by the bast fibers of paper mulberry, and silk. The sunlight fastness were not improved in all dyeing conditions.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.6-11
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• 2001

In order to use bast fibers of mulberry tree at a pulp source of Hanji, the bast fibers were microbiologically treated with several wood rot fungi, and the microscopic characteristics of bast fibers depending on treatment days were evaluated. By wood rot fungi, Phanerochaete chrysosporium and Trametes versicolor, the weight reduction ratio was approximately 50 percent within incubation for 20 days. occurring together with decomposition of useful fibers. However, Hwterobasidion insularis and Stereum hirsutum have completely decomposed the utmost layer of black blue colored bast fibers, and not caused the damage if fibers. Until incubation for 10 days, the cellulose content of vast fibers by Stereum hirsutum was 78.9 percent with lignin content of 7.2 percent, showing an appropriate decomposition for useful fibers. By microscopic observation, the bundled fibers were separated to single fiber within treatement days 30 by Pleurotus ostreatus, and there were no damage on the surface of fiber by treatment days 50.

• Journal of the Korean Wood Science and Technology
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• v.33 no.3 s.131
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• pp.79-88
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• 2005

This research studied the utilization of the bed log wastes as a papermaking grade pulp. Five different bed log samples from shiitake mushroom (Lentinus edodes (Berk.) Sing) cultivation were collected by the cultivating periods of 1 to 5 years. The wood chemical composition and the characteristics of kraft pulping of each sample were investigated. The results of chemical composition showed that the rate of carbohydrate (glucose and xylose) content in sapwood was decreased as the cultivation period was increased. In heartwood, there was no significant difference. The screening yield of non-cultivated bed log from kraft pulping was higher than that of cultivated one, but the reject of cultivated one, especially for 5 year-cultivated, was lower than non-cultivated bed log. The fiber length and width was continuously decreased as the cultivation period was increased. Therefore, the freeness of the pulp from the cultivated bed log was sharply decreased comparing to non-cultivated due to the fiber cutting and the increased fine content. The dry strengths were increased according to the increasing addition level of bed log kraft pulp to KOCC and non-cultivated wood pulp. From the overall results, the pulp from 5 years cultivated bed log can be reasonably used if it is mixed with long fiber pulp for advantages such as reducing beating time.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.9-16
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• 2004

This research was carried out to investigate the component isolation method from liquefied waste paper. and isolated component was analyzed by molecular weight distribution with gel chromatography and nitrobenzene-oxidation analysis. In the aspect of liquefaction ratio, wet defibration fiber are better than dry defibration fiber because of wet defiberation fiber was easy to access of chemical solution. The optimal liquefaction condition of waste paper was treated at 190℃ for 60 min(cresol 2 ㎖, water 4 ㎖, phosphoric acid 0.5 ㎖ based on waste paper 1 g). In the liquefied waste paper, lignin and carbohydrate were separated with two interfacial layer(cresol layer, water layer). In the chemical analysis of isolated lignin, molecular weight distribution of isolated lignin was below 1,000.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.463-469
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• 2015

In this study, to improve bending strength performance of Korean white pine, we made the curved composite glulam that was reinforced with glass fiber materials and larch lamina. Five types of Korean white pine curved glulams were made depending on whether they had been reinforced or not and how they had been reinforced. Type-A, reference specimen, was produced only with Korean white pine lamina, and Type-B was with larch lamina in the same thickness. Type-C was made by inserting a glass fiber cloth of textile shape between the each layer. Type-D was reinforced with two glass fiber cloths, which were placed inside and outside of the outermost lamina. Type-E was reinforced with GFRP sheet in the same way as Type-D. As a result of this bending strength test, the modulus of rupture (MOR) of Type-B, Type-C and Type-E were increased by 29%, 6%, and 48% in comparison with Type-A. However, MOR of Type-D was decreased by 2% in comparison with Type-A. In the failure modes, Type-A, Type-B and Type-C were totally fractured at the maximum load. However, load values of Type-D and Type-E decreased slowly because of reinforcement of fracture suppression, and the GFRP sheet (Type-E) had better reinforcing effect on compressive stress and tensile stress than the glass fiber cloth (Type-D).

• Journal of the Korean Wood Science and Technology
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• v.40 no.5
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• pp.352-362
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• 2012

Mass transfer behavior in wood was estimated through its microscopic structure. The diffusion coefficients which were decided by theoretical equations are influenced by different anatomical properties of wood. From the experiment, the moisture flux was linear to the square root of time. The diffusion coefficients had a regular tendency during the time elapse. During the modeling, it is necessary to understand the limitation of parameters and consider the particular situation to be simulated. In hardwood, because the apertures were not considered, tangential mass transfer simulation was totally different from experiment. As a result, a hardwood model design should consider the apertures which are even on the fiber walls.

• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.16-22
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• 2007

The behavior of ramie fibers and some wood elements in the early stage of alkali swelling was examined. When the fibers were treated with alkali solution, they significantly shrank in length and swelled in wall thickness. Ramie fibers showed a shrinkage averaging 23% in length and a swelling averaging 92% in width in 100 seconds treating time. Dimensional changes showed different fashion in each element of woods. The tracheids of latewood especially in Pinus densiflora and Larix kaempferi woods swelled intensively and showed balloon swelling, but in the case of Cryptomeria japonica, it was hardly observed. The swelling morphology of libriform fibers was similar to that of tracheids. The walls of vessel elements and parenchyma cells also swelled considerably in thickness but, no balloon swelling was found in both elements. The differences of swelling in different elements can be interpreted in terms of the differences of organization and/or chemical components of the cell walls.