• Transactions of the Korean hydrogen and new energy society
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• v.29 no.5
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• pp.411-418
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• 2018

The polymer electrolyte membranes, CL-SPEEK/Cellulose composite membrane I, II, III with the improved electrochemical and mechanical properties were prepared and characterized. The engineering plastic polyether ether ketone (PEEK) and cellulose were sulfonated and cross-linked. The membranes were prepared by sol-gel casting method with different amount of cross-linking reagent. In conclusion, the composite membranes I, II, III showed improved thermostability, tensile strength and oxidative durability. Proton conductivity of the membranes was also improved and the composite membrane I showed 0.1312 S/cm at $80^{\circ}C$ which was the best of those composite membranes.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.56-61
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• 2011

Alkyl vinyl ethers such as methyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether and isobutyl vinyl ether are usually used as industrial solvents and chemical intermediates in the chemical or pharmaceutical industry. Recently, they are popularly used as raw materials for polymer electrolyte membrane fuel cells and as cellulose dyeing assistants. However, very few investigations about process design and operation data were reported for alkyl vinyl ether compounds and there are no data for propyl vinyl ether(PVE) systems as far as we know. In this work, the isothermal VLE data are reported at 333.15 K for the ternary systems of {PVE + ethanol + benzene} by using headspace gas chromatography(HSGC) and these VLE data were correlated using Wilson, NRTL and UNIQUAC equations. The excess volumes($V^E$) and deviations in molar refractivity(${\Delta}R$) data are also reported for the sub binary systems {PVE + ethanol}, {ethanol + benzene} and {PVE + benzene} at 303.15 K. These data were correlated with Redlich-Kister equation. In addition, isoclines of $V^E$ and DR for ternary system {PVE + ethanol + benzene} were also calculated from Radojkovi equation.

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1153-1158
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• 1999

β-Cyclodextrin, amylose, and cellulose were partially methylated and acetylated in order to examine the relative reactivities of 2-, 3-, and 6-OH groups to alkylation and acylation. The partially methylated samples of the polysaccharides were treated with excess of ethyl iodide and sodium hydroxide in dimethyl sulfoxide to convert all of the free hydroxyl groups to ethyl ether groups. The partially O-ethylated and O-methylated polysaccharides were reductively cleaved with triethylsilane in the presence of trimethylsilyl methanesulfonate and borontrifluoride etherate (5 : 1 by mole) and the resulting 4-OH group was acetylated and benzoylated to form mixtures of eight 4-O-acyl-1,5-anhydroalditols. The relative ratio of the alditol esters were analyzed by gas chromatography to determine the degree of substitution at each position. A similar sequence of reactions was carried out with partially acetylated polysaccharides. The results indicated that the order of relative reactivities for methylation are 2-OH > 6-OH > 3-OH and for acylation are 6-OH > 2-OH > 3-OH regardless of the anomeric configuration.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2403-2412
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• 2018

The present study was aimed at evaluating the effect of variable sodium carbonate ($Na_2CO_3$) loading during wet air oxidation (WAO) pretreatment of rice straw in reducing biomass recalcitrance. The research study was intended to increase the cellulose recovery, hemicellulose solubilization, lignin removal in the solid fraction and limiting the generation of inhibitors in the liquid fraction while reducing the chemical input. The operating condition of $169^{\circ}C$, 4 bar, 18 min and 6.5 g/L $Na_2CO_3$ loading resulted in maximum cellulose recovery of 82.07% and hemicellulose solubilization and lignin removal of 85.43% and 65.42%, respectively, with a total phenolic content of 0.36 g/L in the liquid fraction. The crystallinity index increased from 47.69 to 51.25 along with enzymatic digestibility with an increase in $Na_2CO_3$ loading from 0 to 6.5 g/L as a result of removal of barriers for saccharification via effective cleavage of ether and ester bonds cross-linking the carbohydrates and lignin as indicated by FT-IR spectroscopy. A further increase in the $Na_2CO_3$ loading to 9.5 g/L did not significantly increase the sugar release. Thus, it was concluded that 6.5 g/L $Na_2CO_3$ during WAO is sufficient to increase the delignification and deacetylation, leading to significant changes in apparent cellulose crystallinity inter alia improvement in cellulose accessibility and digestibility of rice straw.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.117-122
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• 1996

The purpose of this study is to investigate the properties of underwater concrete using three kinds of cellulose ether which has viscosity and water retention. The result is that water retention in underwater concrete shows in inverse proportion to PH value and the compressive strength is almostly effected by water retention. It can be certificated by the zeta electro potential value of an undispersed underwater concrete.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1701-1704
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• 2001

The evaluation of structural carbohydrate losses and its effect on silages digestibility in alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) was studied during 5, 21 and 56 days ensiling. About 70 and 60 kg fresh matter of the two forages were ensiled in 9 silos of 120 L capacity. The digestion trials were conducted in two phases using the two grasses in two $4{\times}4$ Latin square design according to the four treatments being the grass and the three silages. There were no differences in the DM and CP contents resulting from 5 to 56 days ensiling in both forages. The water-soluble carbohydrates (WSC), hemicelllose, pectin, and energy were slightly reduced and appeared lower in 56 days silage. The ether extract and cellulose contents slightly increased as the ensiling process advanced in the two species. Hemicellulose losses of 29 and 41 g/kg DM were obtained in alfalfa and orchardgrass, respectively, 56 days after ensiling. While the cellulose losses in both species were very little, compared to that for hemicellulose, the pectin losses, 56 days after ensiling were 15 and 12 g/kg DM in alfalfa and orchardgras respectively. The total structural carbohydrates lost (ie., hemicellulose + cellulose + pectin) in g/kg DM of fresh material forage ensiled, is about four fifths the amount lost by WSC, in alfalfa and about two thirds, in orchardgrass, by 21 days ensiling after the activity of microorganism terminated, indicating that appreciable amount was used as substrate for silage fermentation. Ensiling alfalfa and orchardgrass for 0, 5, 21 and 56 days maintained a decreasing trend of 83.8, 82.5, 79.3 and 78.9% digestibility in alfalfa and 80.5, 77.0, 77.1 and 76.4% digestibility in orchardgrass. While the digestibility of cellulose and ether extract increased in silage in both species, the digestible energy values in silage were reduced from 2.6 to 2.3 and 2.9 to 2.7 Mcal/kg DM respectively in alfalfa and orchard during 5-56 days ensiling.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.357-363
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• 2011

In relieving local pains, ropivacaine has been widely used. In case of their application such as ointments and creams, it is difficult to expect their effects for a significant period of time, because they are easily removed by wetting, movement and contacting. Therefore, the new formulations that have suitable bioadhesion were needed to enhance local anesthetic effects. The effect of drug concentration and temperature on drug release was studied from the prepared 1.5% Carboxymethyl cellulose (CMC) (150MC) gels using synthetic cellulose membrane at $37{\pm}0.5^{\circ}C$. As the drug concentration and temperature increased, the drug release increased. A linear relationship was observed between the logarithm of the permeability coefficient and the reciprocal temperature. The activation energy of drug permeation was 3.16 kcal/mol for a 1.5% loading dose. To increase the skin permeation of ropivacaine from CMC gel, enhancers such as saturated and unsaturated fatty acids, pyrrolidones, propylene glycol derivatives, glycerides, and non-ionic surfactants were incorporated into the ropivacaine-CMC gels. Among the enhancers used, polyoxyethylene 2-oleyl ether showed the highest enhancing effects. For the efficacy study, the anesthetic action of the formulated ropivacaine gel containing an enhancer and vasoconstrictor was evaluated with the tail-flick analgesimeter. According to the rat tail-flick test, 1.5% drug gels containing polyoxyethylene 2-oleyl ether and tetrahydrozoline showed the best prolonged local analgesic effects. In conclusion, the enhanced local anesthetic gels containing penetration enhancer and vasoconstrictor could be developed using the bioadhesive polymer.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.155-161
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• 2018

For the efficient recovering of collapsed sloped soil, using a soil binder that can support the soil strongly and help the growth of plants is very important. The soil binder should also have functions of recovering the soil ecologically as well as be environmental friendly materials. In this research, optimum values of the water content and permeability and direct shear strength were searched by adding the water absorbent and coagulant into the soil binder. The polyacrylamide (PAM) with various anionic strength, super absorbent polymer (SAP) and cellulose ether (CE) were used as a soil binder, water absorbent and coagulant, respectively. Effects of the soil binder on the characteristics of soil were observed by changing the mixing ratio of PAM, SAP and CE. Experimental results showed that the soil binder increased the direct shear strength tens of times and the water content around two times, whereas decreased the water permeability. Also, the addition of CE to increase the coagulation of SAP increased more of the direct shear strength and water content.

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.2
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• pp.12-20
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• 1989

Distribution of benzo(a)pyrene (BaP) in Seoul surface soils was investigated with a simple micro-analytical method consisting of ultrasonic extraction, one-dimensional dual band thin-layer chromatographic separation (TLC) and spectrofluorometric determination. The TLC was done in the following condition: thin-layer plate; Kieselguhr G/Acetylated cellulose, Developer; 1st; ether, 2nd; methanol-ether-water (4:4:1, V/V). The results thus obtained were as follows; 1. All the samples collected from various areas were contained detectable amount of benzo(a)pyrene. The range and average of benzo(a)pyrene contents in Seoul areas are 0.20 $\sim$5.90ppm and 1.01 ppm, respectively. 2. Benzo(a)pyrene contents in soils obtained from commercial areas were much higher than those in industrial and residential areas. The contents range in commercial, industrial, and residential areas are 0.31 $\sim$ 5.90 ppm, 0.36 $\sim$ 1.22 ppm and 0.20 $\sim$ 0.67 ppm, respectively. 3. Benzo(a)pyrene contents in soils from major roads were far higher than those from side or park roads. The ranges of benzo(a)pyrene contents in major, park and side road are 0.40 $\sim$ 5.9 ppm, 0.20 $\sim$ 0.70 ppm, 0.31 $\sim$ 1.30 ppm, respectively. These findings suggest strongly that surface soils in Seoul city are polluted by benzo(a)pyrene probably emitted automobiles.

• Polymer(Korea)
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• v.25 no.2
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• pp.279-292
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• 2001

Two kinds of (hydroxypropyl)cellulose(HPCs) with different molar substitution (MS) and three types of derivatives based on the HPCs: (acetoxypropyl)celluloses, (ethoxypropyl)celluloses, and (cyanoethoxyprofyl)celluloses were synthesized, and their thermal and mesomorphic properties were investigated. All samples, which exhibit cholesteric reflection colours at room temperature, formed right-handed helicoidal structures whose optical pitches (λ$_{ms}$ ) increase with temperature. However, the isotropization ($T_{i}$) and glass temperatures, the magnitude of λ$_{m}$ of the mesophase at the same temperature, and the temperature dependence of λ$_{m}$ of the investigated derivatives highly depended on MS and the length and structure of the side chain introduced in HPC. The results were discussed in terms of the difference in the polarity and flexibility of the substituents and the distance between the main chains. For all derivatives, Am values approached infinity at temperatures above the $T_{i}$, of the mesophase, and no reversal in the sense of the pitch with temperature was detected.