• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.28-33
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• 1994

The chemical compositions of pine bark from mechanical pulp industry were determined, and effect of Ca base acid sulfite on bark cooking was investigated under various conditions. The pine bark was composed of 39.5 % alkali extractives, 50.3 % lignin, and a small amount of carbohydrate. The contents of alkali extractives and lignin were remarkably higher than those of pine wood. The bark was composed of high content of arabinose and xylose, while the wood was composed of high content of mannose. When pine bark was cooked with 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid, but it was very difficult to delignify the bark by 50 % and over under these conditions. In the presence of 60~65 % free acid and at 155~165 $^{\circ}C$, initial cooking rate, delignification, and delignification selectivity were considerably increased, but condensation reaction of lignin was considerable at the end of cooking. Therefore, it was shown that pine bark was very difficult to delignify by the Ca-base acid sulfite cooking.

• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.51-56
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• 1996

The Bark lignin(alkali- and acid lignin), bark extractives(hot water-and $Na_2SO_3$ extractives) of Quercus acutissima and Pinus densiflora, and flavonoids were used to detect heavy metal adsorption. The adsorption ratio of heavy metals by lignin was assigned for 40 to 50%, but was not dependent on lignin kinds. However, in case of the addition of light metals such as $Ca^{++}$ and $Mg^{++}$ to lignin the adsorption ratio was increased by 20 to 40%, and $Pb^{++}$ was almost completely adsorbed. On hot water extractives, the adsorption ratio was very low because the substrate was water-soluble, so the substrate should be water-insoluble to adsorb the heavy metals. However, the adsorption ratios of $Cd^{++}$ and $Pb^{++}$ on $Na_2SO_3$ extractives were significantly increased, while those of $Zn^{++}$ and $Cu^{++}$, were similar to lignin. When four kinds of heavy metals were treated to $Na_2SO_3$ extractives together, more than 97% of $Pb^{++}$ and $Cu^{++}$ was adsorbed_ and $Zn^{++}$ was more adsorbed by 40%, and $Cd^{++}$ was not changed, comparing with the case that on kind of heavy metal was treated. There were differences between adsorption ratio of the kinds of flavonoids and heavy metals, and the adsorption ratio of heavy metals was assigned to 20 to 45% per 0.1g flavonoid.

• The Plant Pathology Journal
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• v.26 no.4
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• pp.394-401
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• 2010

Resin flow, symptom development, and lignin biosynthesis in response to wounding and fungal inoculation were investigated in Pinus rigida and Pinus densiflora. The two-year-old seedling stems were subjected to three types of treatments: (i) wounding without inoculation, (ii) wound-inoculation with a conidial suspension of Fusarium circinatum, and (iii) pre-wounding woundinoculation with the fungus 20 days after the initial wounding. Resin flow from wounding sites was more evident in P. rigida than P. densiflora in all treatments. The wound-inoculation with the fungus induced almost two-fold higher levels of resin flow than the other treatments in both species. The pre-wounding woundinoculation appeared to result in a decrease in pitch canker development in the two pine species. Some reductions in disease severity were observed in the prewounding wound-inoculated P. rigida, showing a mean disease severity of less than 85%, compared with approximately 100% in the wound-inoculated stems. Disease severity was approximately 50% in the woundinoculated P. densiflora, whereas 10% in the pre-wounding wound-inoculated stems. Higher amounts of lignin were found from bark (ca. 40%) than from xylem (ca. 30%). The wound-inoculated bark and the pre-wounding wound-inoculated bark exhibited higher amounts of lignin among the other treatments. These results suggest that the wound-inoculation apparently prompt the increase in resin flow and lignin biosynthesis from the two pine species, and the prior wounding may be involved in decreased disease severity against the further invasion of F. circinatum.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.74-82
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• 2011

The bast fiber of Paper mulberry has been generally used as a fibrous raw material in traditional Hanji-making. Nowadays, its uses is expanded to different special purposes such as paper mulberry yarn, laminated paper, antimicrobial paper depending on its application. Despite the wide array of the use of mulberry fibers, it is still limited due to some difficulties in the automation process of manufacturing works. This study is focused on the analysis of chemical components and morphological properties of paper mulberry bark for the automation of bark peeling process. The bast tissue of paper mulberry was separated in three plies; black outer layer, green inner layer, and white inner layer. The total lignin content, holocelluloses, extractives and ashes, and the anatomical structure of the three layers in mulberry bark tissue were investigated. The analysis showed that the black outer layer is composed of about 50% of total lignin content, whereas the white inner layer is composed of about 90% of holocellulose content.

• Journal of the Korean Wood Science and Technology
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• v.16 no.2
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• pp.90-97
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• 1988

The rate of utilization of the oak cork (bark of Quercus variabilis Blume) ranges only 40-50%. Therefore, this study was carried out to investigate the chemical properties of the oak cork for increasing the utility. 1) The contents of alkali extractives, organic solvent extractives and ash in the oak cork are similar to those of other barks, but hot and cold water extractives and lignin contents are lower than those of the wood. The carbohydrate (cellulose and hemicellulose) content of the oak cork is similar to that of other barks. The suberin contents in the first and the second bark of the oak cork are 34.8 and 32.2% respectively, in the dry weight. 2) Inorganic component contents of the first bark are similar to those of the second. The pH of the first and the second bark are 3.9 and 4.2%. The caloric values of the first and second bark are 6,263 Kcal/kg, and 5,828 Kcal/kg, respectively, and these caloric values are higher than those of other barks. The sclerencymatous cell content of the first bark which is related to the quality of the oak cork is lower than that of second bark, the contents of the sclerenchymatous cell and lignin show the positive correlation. 3) In the dimension of the cross sectioned cork cell, the first bark is bigger than that of the second. The shape of the cork cell is globular shape in the early bark and discoid shape in the late bark. The cross and the radial section are the same shape, but the tangential section shows difference from the other section.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.4
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• pp.66-73
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• 2000

Alkaline sulfite-anthraquinone(AS-AQ) cooking process has been applied to unground pine bark. The properties of the spent liquor such as molecular weight distributions, sulfonic equivalent weights, degree of sulfonation, phenolic hydroxyl groups and kaolin dispersing ability have been investigated to evaluate the possibility of using this liquor as concrete additives or binders. In the case of ground bark meal, more than 90% delignification was achieved at the optimal cooking conditions. However, applying these conditions on unground bark the delignification was slightly retarded. The decrease in the degree of delignification may be attributed to less penetration and diffusion of chemicals during the cooking of the bark. Increasing the cooking temperature only by $5^{\circ}C$ improved the delignification of the bark and about 90% delignification can be achieved. These results indicate that bark can be used successfully during AS-AQ cooking without any mechanical or physical pretreatment. The properties of lignin or polyphenol sulfonates in the spent liquor after AS-AQ cooking of the bark were compared with Sunflo-R, which is commercial lignosulfonate(CLS) prepared from wood. The weight average molecular weights(Mws) estimated by gel-filteration chromatography was found to be ranging from 1,200~1,800. These are considerably lower than those in CLS. Lignin or polyphenol sulfonates in the spent liquor of bark and CLS have similar degree of sulfonation, but the phenolic hydroxyl group was 1.8 times higher than CLS. Moreover, the dispersing abilities of the spent liquors were better than that of CLS, especially after 0.1% addition to kaolin suspension.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.4
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• pp.59-66
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• 2011

This study was carried out to develop the automation bark peeling process of paper mulberry for making Hanji. Nowadays, almost raw material has been imported from south-east asia for making Hanji. Raw material dependence is very high for Hanji-making by low productivity in korea. This study is focused on the resolution for problem of bark peeling automation. Water and sand jet of compressed air was possible bark peeling for black bast fiber. The effect of removing black bast fiber increased the longer the steaming time. Also using drum of bark peeling showed that results under temperature $80^{\circ}C$ and Rpm 50/min were best bark peeling and separating bast fiber from stem. The contents of holocellulose, lignin, ethanol-benzene extractives, and ash were 91.63~95.55%, 1.4~2.0%, 1.12~1.65%, and 1.4~4.3%, respectively. Chemical characteristics are similar between imported raw-material with drum bark.

• Journal of the Korean Wood Science and Technology
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• v.22 no.2
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• pp.54-60
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• 1994

The pine bark from mechanical pulp industry was cooked with bisulfite liquor, and the chemical and physical properties of the spent liquor after cooking for 90 minutes, which allowed partial defibration were determined. Lignosulfonate or lignin-related materials in the spent liquor have a molecular weight of approximately 3,000, which is lower than that of commercial lignosulfonate (C-LS) prepared from wood. The sulfonic equivalent weight calculated by colloid titration was 307 for C-LS, 238~239 for spent liquor. The contents of lignosulfonic acid and phenolic hydroxyl groups on $C_9$ unit of lignin in the spent liquor were 0.98~0.99, and 1.51~1.66, respectively. These values were remarkably higher than those of C-LS. Especially the content of phenolic hydroxyl group was almost twice that of C-LS. The viscosity of spent liquor after freeze drying was very low compared to C-LS. The dispersing ability of spent liquor was almost equivalent to or more than that of C-LS.

• Journal of Korean Society of Forest Science
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• v.40 no.1
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• pp.63-69
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• 1978

A bark comprises about 10 to 20 percents of a typical log by volume, and is generally considered as an unwanted residue rather than a potential1y valuable resourses, As the world has been confronted with decreasing forest resources, natural resources pressure dictate that a bark should be a raw material instead of a waste. The utilization of the largely wasted bark of genus Pinus, Quercus, and Populus grown in Korea can be enhanced by learning their chemical properties. However, the chemical study of tree bark grown in korea have never been undertaken. In the present paper, the studies on the chemical properties of bark comprise carbohydrates, lignin, and extractives, composition of reducing sugars and five essential elements. The results may be summarized as follows: 1. Bark are much richer in quantity of lignin and extractives than the corresponding wood, and are chiefly consisted of lignin, extractives and carbohydrates orderly. It is the same with ash contents. Alcohol-benzene extractives of populus bark are the highest among three genus. 2. Although glucose constitutes the major sugar in both pine and hardwoods bark, in pinus, arabinose and xylose are the next but in hard woods, the next is xylose. 3. Essential elements, Ca and Kjeldahl-N are higher in the bark than in the wood. Ca content is the highest among others, and N,K followed it. Essential elements are higher in Quercus than in Populus and pinus.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.706-710
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• 2010

Understanding of chemical composition and energy contents in tree is important to develope strategies of renewable energy policy to cope with climate change. Residual biomass as renewable energy source was evaluated and focused on the bark-containing branches. Chemical analysis studies were conducted for different part of yellow poplar (Liriodendron tulipifera), which were partitioned to inner bark, outer bark, small branches, medium branches, big branches and trunk. The variations in hydrophobic extractives, hydrophilic extractives, lignin, carbohydrate compositions, energy contents (higher heating value) and the ash content were determined. The inner and outer bark had higher ash content, hydrophobic and hydrophilic extractives content, and higher energy content than those of tree trunk. Polysaccharides content in inner and outer bark was quite lower than those of stem or branches. Based on the energy content of residual biomass, replacement of fossil fuel and greenhouse gas emission abatement were calculated.