• Journal of the Korean Wood Science and Technology
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• 제31권6호
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• pp.1-7
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• 2003

The phase transformation from cellulose I into cellulose II in woods by way of Na-cellulose I was examined by x-ray diffraction analysis.The formation of Na-cellulose I in woods increased with the increase of treating time in alkali solution. When compression wood was treated with 20% NaOH solution at room temperature for 1 day, the x-ray diagram showed only Na-cellulose I. On the other hand, the x-ray diagram of tension wood showed a mixture of cellulose I and Na-cellulose I. Cellulose I of tension wood could not be transformed completely into Na-cellulose I even after 10-day treatment, but was transformed into Na-cellulose I after 30-day treatment. Na-cellulose I of compression and tension woods was converted to the cellulose I pattern and the mixture of cellulose I and cellulose II, respectively, after washing with water and drying at 20℃. Cellulose I regenerated from Na-cellulose I in wood could not be converted to cellulose II by delignification. Thus, it revealed that the delignification of the alkali-treated wood did not affect their cellulose structures. From the results, therefore, it can be concluded that lignin in woods prevents the formation of the stable Na-cellulose I and the conversion from cellulose I to cellulose II. This means that the conversion of chain polarity of wood cellulose hardly occurs during mercerization because cellulose microfibrils are fixed by lignin which not to be intermingled.

• Journal of the Korean Wood Science and Technology
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• 제24권3호
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• pp.72-79
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• 1996

Cellulose I에서 Cellulose II로의 결정변태기구를 X선 및 전자선 회절법과 현미경적 방법을 이용하여 구명하였다. X선 회절 결과, Na-cellulose I을 고온에서 수세할 경우 Cellulose I과 Cellulose II의 혼합형 회절도가, 저온에서 수세할 경우 Na-cellulose IV의 회절도가 얻어졌다. 전자선회절 결과, 고온수세의 시료는 Cellulose I과 Cellulose II의 혼합형이 저온수세의 시료는 Cellulose II의 회절도가 얻어졌다. 또한 고온수세 시료의 전자선회절도로부터 섬유벽의 내측부가 외측부보다 재생 Cellulose I의 양이 많은 것이 확인되었다. 따라서 알칼리 팽윤시 섬유벽내에는 불완전한 팽윤이 발생하는데 그 정도는 내측부가 더욱 심한 것으로 생각된다. 이때 형성되는 불완전한 Na-cellulose I 은 고온 수세의 경우는 탈수에 의해 Cellulose I로, 저온수세의 경우는 수화에 의해 Cellulose II로 변태되지만 완전히 팽윤된 Na-cellulose I은 Cellulose I로 재생될 수 없는 것으로 생각된다. 현미경적 실험결과, mercerization과정에서 cellulose 분자쇄의 packing이나 conformation의 변화와 관련하여 microfibril 의 흐트러짐은 발생하지 않는 것으로 생각되었다.

• Journal of the Korean Wood Science and Technology
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• 제27권1호
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• pp.18-23
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• 1999

3회축을 갖는 Na-cellulose II의 형성조건을 X선회절법을 이용하여 검토하였다. 그 결과 Na-cellulose II는 Na-cellulose I 을 거쳐서 형성되며 결정중의 알칼리농도가 Na-cellulose I 이나 III보다 높은 조건에서 형성되는 것으로 생각되었다. 2회축에서 3회축으로의 섬유주기의 급격한 변화는 알칼리 처리 후의 수분제거방법에 의해 크게 영향받는 것으로 생각되었다. 동(銅)-알칼리셀룰로오스 복합체의 결정은 팽윤상태에서 안정된 구조를 가지며 건조에 의해 결정구조가 변화되었다.

• 한국염색가공학회지
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• 제5권3호
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• pp.221-228
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• 1993

Cellulose acetate and methyl cellulose were synthesized from waste cellulose in order to make waste knit on value added highly. Crystal waste cellulose by oxidation using $HIO_4$ and then acetylation was decrystallized. A degee of crystallinity was measured by X-ray diffraction and the structure was identified by FT-IR spetroscopy, respectively. Cellulose acetate was prepared from the reaction of decrystallized cellulose with acetic acid, cone-$H_{2}SO_{4}$ and acetic anhydride. Also, structure identification by FT-IR and a degree of crystallinity by X-ray diffraction were performed. DS of the synthesized cellulose acetate was 2.8 and viscosity average molecular weight was 238,000. Also, methyl cellulose was synthesized by treating cellulose acetate with NaOH and iodomethane. DS of the synthesized methyl cellulose was 3.0. Glucose unit with three hydroxy groups was all substituted by methoxyl groups. It was identified by FT-IR spectroscopy. Also, the thermal properties of the synthesized methyl cellulose were examined by DSC. It shewed two shewed melting peaks at 22$0^{\circ}C$ and 24$0^{\circ}C$ in the 2nd scan. It proved that DS=3.0 of methyl cellulose was a thermotropic liquid crystal.

• Journal of the Korean Wood Science and Technology
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• 제23권3호
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• pp.1-7
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• 1995

The crystal transformation from cellulose I to cellulose II during alkaline swelling of waste wood, which has been used for cultivating oak mushroom(Cortinellus edodes (Berk.) Ito et Imai), was investigated and compared to that of normal wood by a series of X-ray diffraction analysis. When the sapwood of cultivated wood was treated with 20% NaOH solution for 2 hours, the cellulose I can be easily transformed into Na-cellulose I than normal wood or heartwood of cultivated wood. Certainly the formation of Na-cellulose in wood is proportional to alkali swelling duration, and the formation of cultivated sapwood was faster than that of the other woods. Cellulose I in the sapwood of cultivated wood was easily transformed into cellulose II during mercerization, but the sapwood of normal wood and the heartwood of cultivated wood hardly converted to cellulose II. Namely, most of Na-cellulose I in normal wood can be reconverted to cellulose I in the process of washing and drying. Therefore, it can be concluded from this study that in cell wall lignin and hemicellulose can prevent the alkaline swelling of cellulose in wood and the transformation from cellulose I to cellulose II as well.

• Asian-Australasian Journal of Animal Sciences
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• 제7권2호
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• pp.207-212
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• 1994

Effects of dietary cellulose and protein levels on nutrient utilization in chickens were investigated. Four experimental diets containing 5% (low cellulose) or 20% (high cellulose) cellulose in combination with 10% (low protein) or 20% (high protein) protein of 70 g/day were alternatively forced-fed to eight colostomized White Leghorn cockerels once a day to make $4{\times}4$ Latin-square design. The digestibilities of DM and energy decreased with the increase in cellulose level, but not affected by dietary protein level. Ether extract digestibility was higher in the high cellulose diets than in the low cellulose protein level. Ether extract digestibility was higher in the high cellulose diets than in the low cellulose diets. The digestibility of nitrogen free extract had the same trend with the digestibility of DM and energy. The digestibility of acid detergent fiber was not so much different among the diets, but the NDF digestibility was lower in the high cellulose diets than in the low cellulose diets, due to the low hemicellulose digestibility. The true digestibility of protein was influenced by both of the dietary protein and cellulose levels, and their interaction was found. The dietary protein level affected the biological value of protein but the dietary cellulose level did not, and consequently the biological value of protein in the low protein diets was lower than in the high protein diets.

• 폴리머
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• 제37권3호
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• pp.362-372
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• 2013

새로운 방법에 의하여 제조된 셀룰로오스-NMMO pre-dope를 이용한 셀룰로오스 섬유 및 필름 제조를 위한 압출가공 시 열분해 및 기계적 분해에 따른 셀룰로오스의 분자량 및 알파 셀룰로오스 함량 변화에 대하여 고찰하였다. 고속분쇄에 의해 제조된 pre-dope를 압출기에 통과시켜 용액으로 제조할 때 가공온도, 셀룰로오스의 농도 및 체제시간에 따라 셀룰로오스의 분자량 및 알파 셀룰로오스 함량 변화가 다양하게 나타났다. 셀룰로오스의 분자량과 알파 셀룰로오스 함량은 셀룰로오스의 농도가 낮을수록 온도가 높을수록 감소하였다. 셀룰로오스 농도 15% 및 짧은 체제시간 영역에서 알파 셀룰로오스 함량은 높은 전단으로 인해 온도가 높을수록 가장 큰 변화를 보였다. 다양한 가공조건으로부터 알파 셀룰로오스 함량변화 거동은 분자량 변화와 다른 거동을 보였으며 셀룰로오스 용액 제조를 위한 압출가공조건이 중요 요인임을 알 수 있었다.

• Applied Biological Chemistry
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• 제40권2호
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• pp.101-106
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• 1997

발효시켜서 만드는 감식초에서 시료를 채취하여 배양하고, pellicle을 형성하는 single colony를 cellulose 생합성균으로 분리하였다. 분리된 균주는 형태적 특성, 알콜의 재산화 등의 생리, 생화학적 특성 등에 의하여 Acetobacter속으로 분류되었으며, Acetobacter CBI-2라고 명명하였다. Acetobacter CBI-2는 정치배양 시에 기존의 생합성 균주로 알려진 Acetobacter xylinum과 대등한 cellulose 생합성 능력을 나타내었다. Acetobacter CBI-2이 생성한 고분자물질의 분해산물을 TLC법으로 확인한 결과 기존 cellulose의 것과 일치하였다. Acetobacter CBI-2에서 genomic DNA를 분리 정제하여 cel A 영역을 probe로하여 hybridization 시킨 결과, 상동성을 나타내어 분리 균주에는 cellulose 생합성 관련 유전자가 존재함을 나타내었다.

• 한국키틴키토산학회지
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• 제23권4호
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• pp.228-233
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• 2018

삼림 토양 시료를 이용하여 cellulase 생산균주를 단리한 결과, Carboxymethylcellulose (CM-cellulose)를 기질로 첨가한 고체배지상에서 명확한 활성환을 형성하는 총 6종류의 cellulase 생산균주를 단리하여, 단리한 균주 유래의 16S rDNA유전자 염기서열 분석을 통하여 균주 동정을 진행하였다. 그 결과 본 연구에서 단리된 균주는 Bacillus subtilis 4종류, Bacillus amyloliquefaciens 1종류, Bacillus cereus 1종류로 동정되었다. 이 중에서 CM-cellulose에 대한 가장 높은 cellulase 활성을 보이는 Bacillus subtilis를 선정하여 Bacillus subtilis NSC로 명명하였다. Bacillus subtilis NSC 유래 cellulase는 균주 배양 36~48시간에서 가장 높은 cellulase 생산성을 보였으며, 최적 pH 및 온도를 검토한 결과, 본 균주 유래 cellulase는 pH 5.0과 $40^{\circ}C$에서 가장 높은 효소 활성을 나타내었다. 그리고, pH 4.0~5.0 조건에서 30분간 효소처리를 하여도 효소활성의 감소가 없었으며, $40^{\circ}C$까지는 30분간의 열처리에도 효소활성의 저하 없이 안정한 특성을 보였다. CM-cellulose, Alkali swollen cellulose, Sigmacell-cellulose, Alpha-cellulose, 그리고 Avicel을 기질로 기질 특이성을 한 결과 CM-cellulose에 대하여 가장 높은 효소 활성을 나타내었으며, cellulose 결정구조를 보유하고 있지않는 CM-cellulose와 Alkali swollen cellulose에 대해서는 명확한 효소활성을 보였다. 하지만, cellulose 결정구조를 보유하고 있는 Sigmacell Cellulose, Alpha-cellulose, 그리고 Avicel 기질에 대해서는 CM-cellulose 활성의 각각 8%, 8%, 그리고 4%의 매우 낮은 효소활성을 나타내었다. Bacillus subtilis NSC 유래 cellulase의 0.26 U/ml 조효소액과 0.52 U/ml 조효소액을 이용하여 CM-cellulose의 분해 특성을 검토하였을 때 두 조효소액 모두 반응 CM-cellulose에 대해 반응 120분 후에 0.43 U/ml와 0.76 U/ml의 효소 활성을 나타내었다.

• Fibers and Polymers
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• 제3권1호
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• pp.1-7
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• 2002

Cellulose carbonate was prepared by the reaction of cellulose pulp and $CO_2$ with treatment reagents, such as aqueous $Zncl_2$ (20-40 wt%) solution, acetone or ethyl acetate, at -5-$0^{\circ}C$ and 30-40 bar ($CO_2$) for 2 hr. Among the treatment reagents, ethyl acetate was the most effective. Cellulose carbonate was dissolved in 10% sodium hydroxide solution containing zinc oxide up to 3 wt% at -5-$0^{\circ}C$. Intrinsic viscosities of raw cellulose and cellulose carbonate were measured with an Ubbelohde viscometer using 0.5 M cupriethylenediamine hydroxide (cuen) as a solvent at $20^{\circ}C$ according to ASTM D1795 method. The molecular weight of cellulose was rarely changed by carbonation. Solubility of cellulose carbonate was tested by optical microscopic observation, UV absorbance and viscosity measurement. Phase diagram of cellulose carbonate was obtained by combining the results of solubility evaluation. Maximum concentration of cellulose carbonate for soluble zone was increased with increasing zinc oxide content. Cellulose carbonate solution in good soluble zone was transparent and showed the lowest absorbance and the highest viscosity. The cellulose carbonate and its solution were stable in refrigerator (-$5^{\circ}C$ and atmospheric pressure).