• Journal of the Korean Wood Science and Technology
• /
• v.31 no.6
• /
• pp.1-7
• /
• 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
• /
• v.24 no.3
• /
• pp.72-79
• /
• 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
• /
• v.27 no.1
• /
• pp.18-23
• /
• 1999

The formation conditions of Na-cellulose II with three fold helix were investigated by an x-ray diffraction method. Na-cellulose II was formed through Na-cellulose I. It seems that the concentration of sodium hydroxide in Na-cellulose II is higher than both those of Na-cellulose I and Na-cellulose III. Na-cellulose II was formed well by different rinsing and drying methods even though the sample treatment was carried out in very short periods of time. Metal-complexed Na-cellulose swollen in the mixture of $Cu(OH)_2$ and sodium hydroxide is stable in wet state, and changed to a different polymorph by drying.

• Textile Coloration and Finishing
• /
• v.5 no.3
• /
• pp.221-228
• /
• 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
• /
• v.23 no.3
• /
• pp.1-7
• /
• 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
• /
• v.7 no.2
• /
• pp.207-212
• /
• 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.

• Polymer(Korea)
• /
• v.37 no.3
• /
• pp.362-372
• /
• 2013

During extruder processing to manufacture cellulose fiber and film using cellulose-NMMO pre-dope produced by a new method, it seems to occur the changes of molecular weight and ${\alpha}$-cellulose content of cellulose upon thermal and mechanical degradation. In an extruder making cellulose solutions from the pre-dope obtained by high-speed mixer, the changes of cellulose molecular weight and ${\alpha}$-cellulose content resulted with the variations of processing temperature, concentration of cellulose, and residence time. The molecular weight and ${\alpha}$-cellulose content of cellulose decreased with decreasing cellulose concentration and increasing processing temperature. At 15% concentration and short residence time region, the change of ${\alpha}$-cellulose content was so high due to high-shear with an increase in temperature. From these processing conditions, the variations of ${\alpha}$-cellulose content and molecular weight showed different behaviors, and these processing conditions for making cellulose solution were found to be important factors.

• Applied Biological Chemistry
• /
• v.40 no.2
• /
• pp.101-106
• /
• 1997

A screening was performed to isolate the cellulose-producing microorganisms from vinegar in Korea. The isolated strain was identified as Acetobacter sp. with respect to physiological and biochemical characteristics and designated as Acetobacter CBI-2. Cellulose production of Acetobacter CBI-2 was equal with the well known cellulose-producing bacteria, A. xylinum. The result of separation on thin layer chromatography(TLC) was consistent with the degradation product of native cellulose. The presence of genes required for the cellulose biosynthesis in Acetobacter CBI-2 was confirmed by Southern hybridization.

• Journal of Chitin and Chitosan
• /
• v.23 no.4
• /
• pp.228-233
• /
• 2018

We isolated microorganisms from soil, which is sampled at forest, Kyeonbuk, Korea, as cellulolytic microorganisms. The isolated strains were identified by analysis of 16S rRNA gene from the starins. The result, four kinds of Bacillus subtilis, one kind of Bacillus amyloliquefaciens, and one kind of Bacillus cereus were identified. Among these strains, Bacillus subtilis was selected due to its high cellulase activity and this strain was named as Bacillus subtilis CNS. The optimum pH and temperature of the cellulase from Bacillus subtilis CNS was pH 5.0 and $40^{\circ}C$, respectively. In the investigation of pH and temperature stability, the cellulase from Bacillus subtilis NSC stabled pH 4.0~6.0 range and until $40^{\circ}C$ for 30 min perfectly. In the enzyme activity for various cellulosic substrate, cellulase from Bacillus subtilis CNS showed the highest activity for CM-cellulose. And, the enzyme activities for alkali swollen cellulose, Alpha-cellulose, Sigmacell-cellulose, and Avicel were approximately 31%, 8%, 8% and 4% of activity for CM-cellulose, respectively. In the degradation of CM-cellulose, the 0.26 U/ml and 0.52 U/ml of cellulase showed 0.43 and 0.76 U/ml activity for CM-cellulose after the reaction of 120 min, respectively.

• Fibers and Polymers
• /
• v.3 no.1
• /
• pp.1-7
• /
• 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).