• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.4
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• pp.18-27
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• 1997

This study was performed to obtained the optimal delignified condition of exploded wood on the acid hydrolysis with sulfuric acid. Wood chips of pine wood(Pinus desiflora), oak wood(Quercus serrata) and birch wood (Betula platyphylla var. japonica) were treated with a high pressure steam (20-30kgf/$\textrm{cm}^2$, 2-6 minutes). The exploded wood was delignified with sodium hydroxide and sodium chlorite, and then hydrolyzed with sulfuric acid. The result can be summerized as follows ; In the exploded wood treated with sodium hydroxide, the optimal concentration of sodium hydroxide was 1% as content of lignin in the exploded wood. Lignin content of exploded wood treated with sodium chlorite was lower then that sodium hydroxide. The maximum reducing sugar yield of exploded wood treated with 1% sodium hydroxide was lower than non-treated exploded wood. In the case of sodium chlorite treated, the maximum reducing sugar yield was hgher than non-treated exploded wood. Sugar composition of acid hydrolysis solution was composed of xylose and glucose residue, and the rate of glucose residue was increased in high pressure condition.

• Journal of the Korean Wood Science and Technology
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• v.23 no.1
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• pp.54-60
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• 1995

This paper reports on the changes of equilibrium moisture contents and specific surface areas of Poplar wood(Populus euramericana) for various steam explosion treatments. Equilibrium moisture contents(EMC) and specific surfaces of steam exploded woods were measured under the moisture adsorption course at 25$^{\circ}C$, and compared with those of other materials and wood meals. The EMCs of steam exploded wood meal were 1~5% less in comparison with that of wood meal. In the case of delignified steam exploded wood meal and delignified wood meal, the same tendency was appeared too. But absolute values of EMCs for delignified wood meals were larger than those of the wood meal. For the changes of EMC by the steam exploded conditions, the EMC decreased with the increase of the steam explosion pressure. On the other hand, specific surface areas were calculated from BET plots based on amounts of monomolecular vapor adsorption of various wood meals. Specific surface areas of the wood meal and delignified wood meal were 90~145, 34~90($m^2/g$) respectively, and which were greater in comparison with those of steam exploded wood meals and delignified steam exploded wood meals. From these results, it is considered that the amount of water vapor adsorption was decreased by the increase of the crystallinity, effect of heat treatment, and coating by melted lignin in during the steam explosion.

• Journal of the Korean Wood Science and Technology
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• v.20 no.4
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• pp.65-72
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• 1992

Steam defiberated pulp and steam exploded wood(birch chip) were extracted with solvents (hot-water, 1% NaOH, MeOH, hot water, 1% NaOH). The properties of residual fiber were examined for the utilization as ruminants feed. The digestibility is 38% in steam defiberated pulp(10kg /$cm^2$-15min) and 62-77% in exploded wood(17-18kg/$cm^2$-2~10min), respectively. The more steam pressure and time increase, the more the digestibility increase. The sugars obtained from extractives is amount from 7% to 13% in asplund pulp and from 7% to 10% in exploded pulp. The sugars was mainly composed of 70-80% xylose. The digestibility of residual fiber which is extracted with solvents is low than these of original fibers. Considering the yield and digestibility as ruminant feed, exploded pulp under 17kg /$cm^2$ for 10min has the best efficiency. The exploded wood gives 75.3% on yield(O. D. chip) and 48% on the digestibility.

• Journal of the Korean Wood Science and Technology
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• v.25 no.4
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• pp.68-74
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• 1997

This research was studied dissolving pulp for rayon production, which is not KP, SP methods but steam explosion and oxygen alkali treatment. The variation of characterization in wood cellulose after steam explosion and oxygen alkali treatment this follows. In the oxygen alkali treatment of exploded pine wood, yield of dissolving pulp was lower than steam-exploded oak wood, and we have obtained dissolving pulp that high purity cellulose, but degree of polymerization was inclined to decrease less than 200. In the case of steam-exploded oak wood, degree of polymerization was higher than steam-exploded pine wood but purity of cellulose was lower than its.

• Journal of the Korean Wood Science and Technology
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• v.17 no.3
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• pp.1-7
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• 1989

This study was performed to obtain the optimal condition that hydrolyzed exploded pine(Pinus densiflora), oak(Quercus serrata) and birch wood(Betula platyphylla var. japonica) by using sulfuric acid. The results obtained were summarized as follows: In hydrolysis of wood meal with sulfuric acid. maximum yield of sugar appeared that pine was 12 hours. oak and birch were 24 hours with 65% sulfuric acid. Futhermore, when wood meal and exploded woods were hydrolyzed with 65% sulfuric acid at $23^{\circ}C$ for 6 hours(primary hydrolysis), diluted to 3% and hydrolyzed again at $100^{\circ}C$ for 2 hours(secondary hydrolysis), the maximum sugar yield of wood meals were 6 hours. those of higher steam exploded pine wood was 3 hours. of lower steam exploded oak and birch woods were 6 hours. The sugar analyses of exploded wood showed that the amount of arabinose and xylose residue rapidly decreased. content of nemicelluose decreased with increase of steaming time and pressure.

• Journal of the Korean Wood Science and Technology
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• v.22 no.2
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• pp.30-36
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• 1994

Steam explosion process is one of the most efficient, pretreatment method for the utilization of lignocellulosic biomass. The carbxymethyl-cellulose(CMC) was prepared with steam exploded wood(EXW), pine(Pinus densiflora) and oak(Quercus mongolica), by standard method using isopropyl alcohol and monochloroacetic acid. The range of water solubility of carboxymethylated pine exploded wood was 45.2~66.8 % and those of oak was 60.7~84.7 %. The degree of substitution(D.S) of carboxymethylated pine exploded wood was 0.11~0.33 and oak exploded wood was 0.48~0.76. The color of carboxymethylated pine and oak exploded wood was brown-black. When carboxymethylated EXW was purified by sulfuric acid, the yield of carboxymethylated wood was lower than non-treated one. However, the color was still brown-black although after delignification. In carboxymethylated EXM prepared after delignification, the water solubility and degree of substitution(D.S) of pine were 81.4~95.9 % and 0.71~0.79, and those of oak were 76.2~89.5 % and 0.79~1.05. The values were higher than non-treated. The degree of substitution of purified carboxymethylated wood prepared with delignified EXM, pine and oak were 0.50~0.71 and 0.70~0.88. The color of carboxymethylated wood was white. In carboxymethylated wood preparde after delignification of EXM, swelling ratio and water retention value of pine were 95.9~96.5 and 580.0~751.2, those of oak were 76.2~89.5 and 124.3~307.6.

• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.26-31
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• 1995

Acetylcellulose(AC) was prepared with steam exploded wood(EXW) and EXW after delignification with sodium chlorite, pine (Pinus densiflora) and oak (Quercus mongolica) woods. The color of acetylated pine and oak exploded wood was brown, degree of substitution(D.S) of pine was 1.47~2.09, and this of oak was 1.49~2.29. The hemicellulose content of acetylated pine and oak exploded wood was 0~3.4% and 1.49~11.3%, individually. The degree of substitution of acetylated wood prepared from delignified EXW in the pine and oak wood was 0.50~0.71 and 0.70~0.88, individually. Hemicellulose content of acetylated EXW with sodium chlorite after delignification in the pine and oak wood was less than 1% and 0.6~2.5%. The color of acetylated wood after delignification was white. IR-spectra of acetylated pine and oak EXW after delignification were found that peaks at around 1740$cm^{-1}$ and 1200$cm^{-1}$ increase markedly, due to ester carbonyl group.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.30-36
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• 1993

Wood chips of oak (Quercus mongolica) and larch (Larix leptolepis) were treated with a relatively low pressure steam(10~20 kg/$cm^2$) for 10~20 min (first-stage),and then increased pressure up to 30kg/$cm^2$ for 30 second (second-stage), and steam pressure was released intentionally to air. Main components of exploded wood were separated with 1% NaOH and hot water-methanol. In this work, the more effective low pressure explosion condition and separation method of wood main component were investigated. The results can be summarized as follows; 1. The yields of exploded wood were generally decreased with increasing steam pressure and reaction time. 2. The proper condition of steam explosion in low pressure for the separation of wood main components was 15kg/$cm^2$-10 min, in oak wood and 20kg/$cm^2$-10 min., then 30kg/$cm^2$-0.5 min, in larch wood. 3. The 23% of elude hemicellulose was obtained from the exploded oak wood which was treated with optimal condition. 4. In the case of hot water-methanol extraction, the ratio of delignification was 14~23% in the exploded larch wood and 42~55% in the exploded oak wood. 5. The methanol was more effective than 1% sodium hydroxide solution for extraction of lignin from exploded wood.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.67-78
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• 2001

Two species(Quercus mongolica, populus euramericana) of hardwood chips were subjected to steam explosion 25 kg/$cm^2$, for 6 min. The exploded woods were treated by the single or multi-stage chemical process with sodium hydroxide, sodium hypochlorite and sodium chlorite. The multi-stage treatment of exploded wood can be successfully removed lignin. Enzymatic hydrolysis rate of substrate varied from 25% for exploded wood to about 80% for the multi-chemical treated exploded wood. The enzymatic susceptibility was different among wood species. The multi chemical treatment of the exploded wood resulted in the high rate of glucose in the enzymatic hydrolyzate. Cellulase adsorption increased at high lignin content of substrates, while crystallinity, pore area and specific surface area of substrates did not affected enzyme adsorption. According to the proposed pretreatment and saccharification process in this study, it can be acquired about 37~40 kg of glucose from 100 kg of hardwood.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.809-827
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• 2017

Steam explosion was applied to extract phenolic compounds from oak wood (Quercus mongolica). The effects of three independent factors (ethanol concentration, extraction temperature and extraction time) on the total phenolic content, DPPH radical scavenging activity, and antimicrobial activity from the steam exploded oak wood were optimized using response surface methodology (RSM). The independent variables were coded at three levels and their actual values were selected on the basis of preliminary experimental results. The following optimal extraction conditions were selected: ethanol concentration 82.0%, extraction temperature $71.7^{\circ}C$, and extraction time 60.5 min for total phenolic content; ethanol concentration 78.3%, extraction temperature $70.3^{\circ}C$, and extraction time 57.6 min for DPPH radical scavenging activity; ethanol concentration 80.6%, extraction temperature $68.4^{\circ}C$, and extraction time 59.0 min for antimicrobial activity. The experimental values agreed with those were predicted within confidence intervals indicating the suitability of RSM in optimizing the ethanol extraction of phenolic compounds from the steam exploded oak wood. Under the optimized conditions, the experimental value of the total phenolic content was 111.8 mg GAE/g dry steam exploded oak wood, DPPH free radical scavenging activity was 65.7%, and antimicrobial activity was 17.0 mm, and those are reasonably close to the predicted values (109.2 mg GAE/g dry steam exploded oak wood, 62.3% and 15.9 mm, respectively).