• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.518-527
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• 2015

In this study, nanocomposite mats consisting of cellulose nanocrystals (CNCs) and poly(lactic acide) (PLA) were electrospun from a suspension mixture consisting of tetrahydrofuran at room temperature. Morphology study showed that fibers of electrospun composite mats were aligned in three dimensional surface along the fiber long-axis. Average diameter of the electrospun fibers decreased with an increase in the CNC loading level. Tensile strength of the electrospun fibers mat decreased with an increase in the CNC loading level because of bead formation in the formed fibers and low interfacial bond strength between PLA and CNC. Meanwhile, thermal stability of the electrospun nanocomposite mats was effectively improved as the amount of CNC increased.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.123.1-123.1
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• 2011

본 연구에서는 THF(Tetrahydrofuran)와 산화탄소나노튜브를 혼합한 유체가 메탄 하이드레이트 생성에 어떠한 영향을 미치는지 알아보기 위해 하이드레이트 생성실험을 수행하고 비교분석하였다. 먼저 하이드레이트 생성 시 정확히 큰 동공에 하나의 THF 분자를 위치시킬 수 있는 5.56 mol%의 THF 혼합유체와 0.003 wt%의 산화 탄소나노튜브를 첨가한 산화탄소나노유체에서 하이드레이트 생성실험을 수행한 결과 같은 과냉도에서 상평형은 THF가 우수하였으며, 하이드레이트 생성에 소모되는 가스소모량은 산화탄소나노튜브가 월등히 우수한 효과를 보였다. 따라서 이 두 종류 촉진제의 단점을 보완하고, 우수한 효과를 이끌어 내기 위해 THF와 산화탄소나노튜브를 혼합하였다. 0.003 wt%의 산화탄소나노유체에 5.56 mol%의 THF를 혼합하였으며, 하이드레이트 상평형, 가스소모량, 생성시간을 측정하여 증류수와 THF, 산화탄소나노유체와 비교하였다. 그 결과, THF+산화탄소나노튜브 혼합유체의 상평형은 THF의 상평형과 비슷하였으고, 과냉도 3.4K에서의 가스소모량은 산화나노유체가 증류수의 3.6배, THF가 증류수의 1.7배, THF+산화탄소나노튜브 혼합유체가 증류수의 5.2배로 THF+산화탄소나노튜브 혼합유체에서 가스소모량이 가장 높음을 알 수 있었다. 또한 하이드레이트 생성시간은 같은 과냉도에서 THF+산화탄소나노튜브 혼합유체가 THF보다 빠르며, 산화탄소나노유체의 하이드레이트 생성시간과 비슷함을 보였다. 따라서 THF+산화탄소나노튜브 혼합유체는 THF의 우수한 상평형 효과와 탄소나노튜브의 높은 가스소모량 효과를 같이 가지고 있음을 확인하였다.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.580-585
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• 2006

UV-thermal dually curable coating materials were prepared by the sol-gel method. Nano-sized colloidal boehmite was treated with various organo silane coupling agents. These materials could be well dispersed in various alcohols and relatively polar organic solvents such as tetrahydrofuran and acetonitrile. The coating films were prepared by a spin coating method on various substrates, which were characterized by FT-IR, Si/Al CP MAS NMR spectra, UV-Vis spectrophotometer, FE-SEM, Taber abraser, haze meter, and pencil hardness tester. The effects of molar ratio and types of silane coupling agents, curing method and ion-shower treatment were investigated. Dually curable coating method offered an optimally good quality film in both hardness and transmittance. The transparency and the hardness of the prepared films were increased with amounts of 3-(trimethoxysilyl)propylmethacrylate, and (3-glycidyloxypropyl)trimethoxysilane, respectively. The adhesion between coated layer and substrate could be enhanced by ion-shower treatment.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.802-808
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• 1996

Silicic acid(SA) was extracted with organic solvents from aqueous sodium silicate solutions acidified with dilute sulfuric acid. Tetrahydrofuran(THF), isopropyl alcohol and acetone were used as organic solvents. The extraction degree of Si and the removal efficiency of Na is determined according to kinds of solvent and the mixing ratios of solvent, sodium chloride and $H_2O$. Optimum conditions for the preparation of high purity SA were THF as an organic solvent, volume ratio of organic solvent/SA : 1 (organic solvent 10ml/10ml SA) and the amount of NaCl addition 2.5g/10ml SA. The extraction degree of Si and the removal efficiency of Na at that point were 86.2% and 99.95% respectively and the purity of SA was 99.96%.

• Journal of the Korean Chemical Society
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• v.50 no.4
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• pp.307-314
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• 2006

The redox characteristics of 2-ketohydrazono-3-phenyl-5-substituted-2,3-dihydro-1,3,4-thiadiazoles and its derivatives (1a-h) has been investigated in nonaqueous solvents such as 1,2-dichloroethane (DCE), dichloromethane (DCM), acetonitrile (AN), tetrahydrofuran (THF), and dimethylsulfoxide (DMSO) containing 0.1 mol.dm-3 tetra n-butylammonium perchlorate (TBAP) as supporting electrolyte at platinum ectrode. Through controlled potential electrolysis, the oxidation and reduction products of the investigated compounds can be separated and indentified. The redox mechanism is suggested and proved. It was found that all the investigated compounds are oxidized in two irreversible one-electron processes following the well known pattern of EC-mechanism. On the other hand, these compounds are reduced in a single two electron or in a successive two one electron processes following the well known pattern of EEC-mechanism according to the nature of the substituent

• Polymer(Korea)
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• v.38 no.5
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• pp.645-649
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• 2014

The causes of residual stress in an injection molded part are high temperature variation and shear stress during molding process. Chemical cracking test is one of the methods of measuring residual stress and cracks are developed according to the degree of residual stress. In this study, the relationship between chemical cracking and exerted stress have been investigated. Deformation jig was designed and used to give a stress through deformation in a specimen. Specimens were molded by a hot press using polycarbonate (PC) and annealed to remove residual stresses in the specimens. Specimens were fixed in the deformation jig and immersed into the solvent to create cracks in the specimens. Solvents were prepared by using tetrahydrofuran and methyl alcohol. As stress accordance with the deformation in the specimen increased, the frequency and density of cracks in the specimen also increased. The results of this study can be used for the measurement of residual stress quantitatively in an injection molded PC product using a chemical cracking method.

• Clean Technology
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• v.14 no.1
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• pp.35-39
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• 2008

In this study, we successfully fabricated a super-hydrophobic polymer layer on the surface of slide glass using the solubility difference of a polymer at two different solvents. After dissolving polystyrene (PS) resins in tetrahydrofuran (THF) as a good solvent and then adding ethanol(EtOH) as a poor solvent, we were able to fabricate super-hydrophobic surface. We also investigated the effect of EtOH addition, coating methods, solution mixing time and speed, and other alcohols on the surface hydrophobicity. The water contact angle (WCA) of the fabricated surface revealed $WCA>150^{\circ}$ and the microporous surface structure composed of microparticles with the size less than $5\;{\mu}m$.

• Journal of the Korean Chemical Society
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• v.30 no.4
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• pp.352-358
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• 1986

An extensive experimental survey on the retention behaviors of phenols in the binary solvent system such as methanol-water, acetonitrile-water and tetrahydrofuran-water as well as the ternary solvent system such as methanol-acetonitrile-water and methanol-tetrahydrofuran-water is presented. A linear equation, which describes the capacity factor as a function of the solvent composition in the mobile phase and is able to predict the retention behaviors of phenols, was obtained. The iso-eluotropic lines for the binary and ternary solvent system are based on the equal strength of the methanol-water solvent which shows an optimum separation of the phenols used. The specific effect of each solute in the binary solvent system appeared to be larger than those in the ternary system.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.59-62
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• 2004

The ammonium ion-selective electrodes ($NH^+_4$-ISEs) based on the tetrahydrofuran(THF)-containing-16-crown-4 derivatives,1,4,6,9,11,14,16,19-tetraoxocycloeicosane ($L^1$) and 5,10,15,20,-tetramethyl-1,4,6,9,11,14,16,19-tetraoxocycloeicosane ($L^2$), were prepared and the electrode characteristics were tested. The conditioned $NH_4^+$-ISEs (E1) based on $L^1$ with TEHP as a plasticising solvent mediator gave best results with near-Nernstian slope of 53.9 mV/decade of activity, detection limit of $10^{-4.9}$ M, and enhanced selectivity coefficients for the $NH^+_4$ ion with respect to an interfering $K^+$ ion (log $K^{pot}_{NH_4^+,K^+}$ = -1.84). This result was compared to other ammonium ionophores reported previously, for example, that of nonactin (log $K^{pot}_{NH_4^+,K^+}$ = -0.92). The proposed electrode showed no significant potential changes in the range of 3.0 < pH < 9.0.

• 보존과학연구
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• s.32
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• pp.61-74
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• 2011

This study examines the removal effects of solvents which were applied on three adhesives and three filling materials for ceramics. The chosen materials are Cemedine C, Loctite$^{(R)}$ 401$^{TM}$, Araldite Rapid Type, plaster of paris, CDKI 520A+B, Araldit$^{(R)}$ SV427-2+HV427-1. For the first examination, each different materials were soaked into different solvents, and then the soften level were compared by compressive pressure. The result of the first exam showed that Cemedine C was dissolved easily in acetone. Furthermore Araldite, CDK and SV427 were soften efficiently by Dichloromethan, Tetrahydrofuran and DMX(Dichloromethan+Methanol+Xylene). However, Loctite and plaster were not able to make sample for the first test. Therefore, the second test carried on only. The second examination, chosen effective solvents from the first test were applied with two different methods; soaking and saturated atmosphere. Almost every sample could removed by soaking method in ten minutes, and saturated atmosphere method needs 24 hours for the safety.