• 펄프종이기술
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• 제45권3호
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• pp.27-35
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• 2013

Cotton linter pre-treatment methods using electron beam and sulfuric acid were investigated to prepare high quality regenerated fibers for fabrics. So far, NaOH was used to reduce the degree of polymerization (DP) of the cotton linter for ease of dissolving by cellulose solvent. Two pre-treatment methods were developed to reduce the consumption of the chemicals (NaOH) and to control the DP of cellulose more precisely. Changes in ${\alpha}$-cellulose contents and brightness by the pre-treatments were also important concerns. Both electron beam irradiation and sulfuric acid were shown to be effective on controlling the DP of cellulose and to reduce the chemical consumption, but reduced ${\alpha}$-cellulose contents as well in this study. Sulfuric acid pre-treatment, which needed additional washing process after the pre-treatment when comparing to the electron beam irradiation method, gave the highest brightness and the highest reduction of ${\alpha}$-cellulose content.

• 한국응용과학기술학회지
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• 제27권4호
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• pp.508-514
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• 2010

Regenerated cellulose fibers were prepared from three pulps containing different degree of polymerization(DP) and $\alpha$-cellulose contents by dry-jet wet spinning technique with cellulose dope in N-methylmorpholin N-oxide (NMMO). The effect of antioxidant, n-propyl gallate (PG) on the properties of different regenerated celluloses was studied using X-ray diffraction, copper number calculation, and viscometry. The degradaqtion of regenerated cellulose from pulp containing higher DP and lower $\alpha$-cellulose content was occurred more seriously. The tensile strength and initial modulus of regenerated cellulose fiber obtained from NMMO dope with PG were higher than those of fiber obtained from NMMO dope without PG. All fibers showed the round shape cross section and typical cellulose II crystalline structure.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.977-982
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• 2013

다양한 종류의 지방산 아실 체인으로 치환된 Cellulose mixed esters(CME)는 재생 가능한 bio-based 폴리머이다. 셀룰로오스 에스터는 생분해성 고분자로써, 분해되지 않는 석유계 플라스틱을 대체할 미래 고분자 소재이다. 본 연구에서는 개질 실험에 앞서 alpha 셀룰로오스를 $40^{\circ}C$의 증류수에 2시간동안 activation하였다. Water-activated 셀룰로오스와, 다양한 불포화 지방산, 무수 아세트산을 $120^{\circ}C$의 lithium chloride/N,N-dimethylacetamide (LiCl/DMAc)용매에서 5시간동안 반응시켜 CME를 합성했다. 세척과 감압을 반복한 후, TGA, FT-IR, 1H-NMR과 FE-SEM를 통해 특성을 관찰하였고, water activation이 셀룰로오스의 수산기 치환에 미치는 영향에 대하여 조사하였다.

• Elastomers and Composites
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• 제31권2호
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• pp.122-129
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• 1996

The Thermal decomposition of the ${\alpha}-Cellulose$ and NaCl was studied using a thermal analysis technique in the steam of nitrogen gas with 30ml/min at various heating ranges from 4 to $20^{\circ}C/min$. The Derivative and Integral method used to be obtained values of activation energy of decomposition reaction. 1. The values of activation energy evaluated by Derivative and Intergral method were consistent with each other very well. 2. The maximum value of heat of decomposition evalated by DSC method was ${\alpha}-Cellulose/NaCl= 90/10$. 3. The thermogravimetric trace curve agreed with the theoretical equation.

• 생명과학회지
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• 제19권10호
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• pp.1432-1437
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• 2009

BC 합성능이 우수하며, 진탕배양에서도 BC를 생산할 수 있는 능력이 있음이 확인된 Aectobacter sp. V6로부터 BC 생산을 위한 당밀 전처리 조건을 검토하였으며, 생산된 BC의 물리화학적 특성을 검토하였다. 당밀을 배지성분으로 사용하기 위해 전처리를 실시한 결과, 1%의 TP가 BC 생산에 가장 효율적이었다. 전처리한 당밀배지를 이용하여 정치 및 진탕배양에서 생산된 BC의 물리화학적 특성을 조사한 결과, 모든 BC는 유화능이 있었으나 유화 안정능은 낮았다. 또한 모든 BC에서 높은 수분 보유능이 나타났으며, 특히 정치배양에서 생산된 BC는 $\alpha$-cellulose보다 14배 이상 높았다. BC의 점도는 모두 $\alpha$-cellulose보다 높았으며, 점도계 회전속도의 증가에 따라 급격히 감소하였다. FT-IR을 통한 조성 분석에서 BC는 식물성 셀룰로 오스와 차이가 없었으며, XRD를 통한 결정성 분석에서는 모든 BC가 결정성을 나타내었다. BC의 미세구조를 조사한 결과, 모든 BC가 미세망상구조로 이루어져 있었는데, 이로 인해 BC는 식물성 셀룰로오스와는 달리 독특한 물성을 가지는 것으로 판단되었다. 또한 정치배양에서 생산된 BC는 진탕배양에서 생산된 것보다 셀룰로오스 미세섬유가 조밀하게 얽혀있음을 알 수 있었다.

• KSBB Journal
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• 제4권3호
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• pp.215-220
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• 1989

불용성 기질인 섬유소의 고효율 효소당화에 적합한 저에너지 소모형 분쇄마찰매체 함유 효소반응기의 개발을 목표로 수평형 회전축에 부착된 paddle에 의해 반응조 내부의 섬유소-분쇄마찰매체-효소의 혼합액을 교반 마찰시키는 horizontal paddle type bioreactor를 제작하여 효용성과 당화조건을 검토하였다. 여러 실험조건하에서 당생성효율과 분쇄마찰매체의 교반시 소모되는 에너지를 다른 두 형태의 bioreactor와 비교 분석함으로서 공업적 활용을 위한 기술적, 경제적 타당성을 비교평가하였다. 표준당화조건은 3mm의 분쇄마찰매체를 500g / L로 첨가하여 200rpm에서 교반할 때였으며, 특히 HPTB는 고농도 기질의 당화에 적합한 bioreactor로 판단된다. 표준당화조건에서 분쇄마찰매체의 교반시 소모되는 동력은 1.7watch/g였으며, 고농도 기질을 이용할 경우 더욱 낮은 동력소모로 당을 생산할 수 있었다. 뿐만 아니라 scale up이 용이할 것으로 예상되는 등 섬유소의 고농도 당화에 적합한 고효율 분쇄마찰매체함유 효소반응기로 판단된다.

• Journal of Nutrition and Health
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• 제30권2호
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• pp.210-219
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• 1997

Retarding effects of the dietary fibers from tangerine peels on glucose, bile acid and cadmium transport were evaluated by dialysis method, and were compared with those of commercial dietary fibers(citrus pection, CM-cellulose, guar gum, $\alpha$-cellulose). Yields of total (TDF), insoluble(IDF) and soluble dietary fibers(SDF) from tangerine peels on the fresh matter basis were 2.84%, 1.95% and 0.39% respectively. The amount of insoluble fibers was 5.2 times higher than that of soluble fibers. Soluble fibers(guar gum, CM-cellulose, SDF, pectin) had the retarding effect on glucose transport, while IDF, TDF and $\alpha$-cellulose did not have. Guar gum showed the greatest effect, followed by CM-cellulose, SDF and pectin. Among the extracted fibers, only SDF had the effect on glucose transport retardation. Regarding bile acid dialysis, guar gum had the greatest retarding effect, and all dietary fibers from tangerine peels, especially SDF, showed the effect of bile acid retardation. On cadmium transport retardation, CM-cellulose had the greatest effect, followed by SDF, TDF, IDF, guar gum and pectin. Among the extracted fibers, SDF had the greatest effect on Cd trasport transport retardation. The extracted dietary fibers showed higher retarding effect on Cd transport than glucose and bile acid transport, and the effect of SDF was higher than IDF.

• Journal of the Korean Wood Science and Technology
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• 제20권2호
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• pp.81-90
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• 1992

The effect of acid treatment of cellulose on the substitution charateristics of carboxymethylation was studied in this paper. Five samples of hydrocellulose(HC), all prepared from ${\alpha}$-cellulose by hydrolysis with five reaction times and determined on average molecular weight and polydispersity, were carboxymethylated to carboxymethyl cellulose (CMC). The CMCs from HCs were examined upon degree of substitution(DS), distribution of carboxymethyl groups in anhydroglucose units of the cellulose, and unsubstituted anhydroglucose(USAG) content. The DS of CMCs increased with increasing the hydrolysis time except CMC from HC at 1 hour hydrolysis time. In carboxymethylation the availability of hydroxyl groups on anhydroglucose units in HCs was the highest on OH(2), and the relative availability of OH(6) increased with the increasing of the hydrolysis time. The USAG contents were more deviated than that calculated based on Spurlin's model, and had a strong tendency of decreasing with increasing the hydrolysis time. The reactivity of HC was lower than that of ${\alpha}$-cellulose and the relative availability of OH(6) in HC increased with the hydrolysis time.

• 한국미생물·생명공학회지
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• 제15권6호
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• pp.375-380
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• 1987

Alcaligenes eutrophus A52의 무세포 추출액으로부터 유안염석 및 DEAE-cellulose 이온교환 크로마토그래피로서 D-$\alpha$-Amino-$\varepsilon$-Caprolactam(DAC) racemase 와 L-$\alpha$-Amino-$\varepsilon$-Caprolactam(LAC) hydrolase를 분획하였다. A. eutrophus A52에 의한 DAC로부터 L-lysine으로의 전환은 DAC가 racemase에 의해 LAC로 전환된 후 hydrolase에 의해 L-lysine으로 가수분해됨을 확인하였다. DEAE-cellulose 이온교환 크로마토그래피에 의해 분리된 racemase의 분획은 최적온도가 55$^{\circ}C$, 최적 pH는 8.0이었으며 hydrolase의 분획은 최적온도가 $65^{\circ}C$ 최적 pH가 9.0이었다. 이 두 효소를 모두 함유하는 무세포 추출 액에 의한 DAC로부터 L-lysine으로의 전환은 6$0^{\circ}C$와 pH8.5에서 최대를 나타내었고 2% 이상의 DAC와 L-lysine에 의해 상당한 저해를 받았으나 0.5% DAC를 3.1mg의 단백질에 상당하는 무세포 추출액으로서 전환시킨 결과 55$^{\circ}C$에서 10시간 동안에 약 98%가 L-lysine으로 전환되었다.

• Journal of Nutrition and Health
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• 제28권9호
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• pp.834-845
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• 1995

This study was conducted in order to establish an in vitro method simulating the physiological function of fibers along the large intestine of humans. Commercial fibers including guar gum, apple pectin, citrus pectin, CM-cellulose, alginic acid and $\alpha$-cellulose, and dietary fiber residues obtained from rice bran, barley, soybean, Korea cabbage, apple, tangerine and sea mustard were employed to determine the water-holding capacity, weight of hydrated residue and fiber content after anaerobic fermentation using human fecal inoculum for 24 hours, followed by dialysis under osmotic suction pressure. The weight of hydrated residue in commercial fibers was in the decreasing order of CM-cellulose > alginic acid, $\alpha$-cellulose > apple pectin, citrus pectin > guar gum and that in food fiber residues was in the decreasing order of rice bran, sea mustard > soybean > tangerine, Korean cabbage > barley > apple. It was demonstrated that the larger the weight of hydrated residue was, the more the weight of human stool increased. Consequently this in vitro method can be used as a preceeding test before undertaking animal or human experiment to predict the physiological effects of fiber residues from diverse food samples as well as commercially refined fibers.