• Journal of the Korean Magnetic Resonance Society
• /
• v.1 no.1
• /
• pp.59-70
• /
• 1997

The interaction of poly(ethylene glycol) (PEG) with cationic dodecyl trimethyl ammonium bromide (DTAB) micelle was studied with electron spin resonance (ESR) by determining line widths of ESR spectra and coupling constant of nitrogen(AN). The degree of ESR line shape change such as line widths and coupling constant indicated that PEG mixes well with DTAB micelle due to a great hydrophobic interaction with surfactant alkyl chains. This suggests that the PEG can be used as non-ionic surfactant to disperse the exposed oil in the ocean.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.3
• /
• pp.324-327
• /
• 1997

Water soluble iridium complex, IrCl(CO)(TPPTS)2·χH2O (1) (TPPTS=m-trisulfonated triphenylphosphine) has been prepared from the reaction of a water soluble complex, IrCl(COD)(TPPTS)2·6H2O (COD=l,5-cyclooctadiene) with CO and unambiguously characterized by electronic absorption, 31P NMR, 13C NMR and IR spectral data. Complex 1 catalyzes the hydration of terminal alkynes to give ketones in aqueous solutions at room temperature. The rate of PhC≡CH hydration dramatically increases with addition of MeOH to the reaction mixture in H2O, which is understood in terms of i) the excellent miscibility between H2O and MeOH and ii) the assumed catalytic hydration pathway involving the initial formation of (alkyne)IrCl(CO)(TPPTS)2.

• Molecules and Cells
• /
• v.45 no.1
• /
• pp.6-15
• /
• 2022

Phase separation is a thermodynamic process leading to the formation of compositionally distinct phases. For the past few years, numerous works have shown that biomolecular phase separation serves as biogenesis mechanisms of diverse intracellular condensates, and aberrant phase transitions are associated with disease states such as neurodegenerative diseases and cancers. Condensates exhibit rich phase behaviors including multiphase internal structuring, noise buffering, and compositional tunability. Recent studies have begun to uncover how a network of intermolecular interactions can give rise to various biophysical features of condensates. Here, we review phase behaviors of biomolecules, particularly with regard to regular solution models of binary and ternary mixtures. We discuss how these theoretical frameworks explain many aspects of the assembly, composition, and miscibility of diverse biomolecular phases, and highlight how a model-based approach can help elucidate the detailed thermodynamic principle for multicomponent intracellular phase separation.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 1999.11a
• /
• pp.32-35
• /
• 1999

Poly(arylene ether phosphin oxide) (PEPO), Udel$^{\circledR}$ P-1700, Ultem$^{\circledR}$ 1000. poly(hydroxy ether) (PHE), carboxy modified poly(hydroxy ether)(C-PHE) and poly(hydroxy ether ethanol amine) (PHEA) were utilized for a coating of carbon fibers. Interfacial shear strength(IFSS) of polymers to carbon fibers was also evaluated in order to understand the adhesion mechanism. IFSS was measured via micro-droplet tests, and failure surfaces were analyzed by SEM. Diffusion between polymer and vinyl ester resin was investigated as a function of styrene content; 33. 40 or 50wt.% and the solubility parameters of polymers were calculated. The results were correlated to the interfacial shear strength. The highly enhanced interfacial shear strength (IFSS) was obtained with PEPO coating, and marginally improved IFSS with PHE, Udel$^{\circledR}$ and C-PHE coatings, but no improvement with PHEA and Ultem$^{\circledR}$ coatings.

• Textile Coloration and Finishing
• /
• v.35 no.4
• /
• pp.221-230
• /
• 2023

Meta-aramid and polyamic acid were separated and the manufactured films were analyzed for their integration and logarithmic properties. The miscibility of meta-aramid and polyamic acid was analyzed by Fourier transform infrared spectroscopy and scanning electron microscopy. Using calorimetric analysis and differential scanning calorimetry, the storage of meta-aramid and polyamic acid, indicated on the right side of the column, was analyzed. It was confirmed that the initial thermal resistance occurs because the polyamic acid is accounted for in the meta-aramid, and the glass transition temperature and persistence phenomenon are explained.

• Applied Microscopy
• /
• v.50
• /
• pp.12.1-12.11
• /
• 2020

Hot stage microscopy (HSM) is a thermal analysis technique that combines the best properties of thermal analysis and microscopy. HSM is rapidly gaining interest in pharmaceuticals as well as in other fields as a regular characterization technique. In pharmaceuticals HSM is used to support differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) observations and to detect small changes in the sample that may be missed by DSC and TGA during a thermal experiment. Study of various physical and chemical properties such sample morphology, crystalline nature, polymorphism, desolvation, miscibility, melting, solid state transitions and incompatibility between various pharmaceutical compounds can be carried out using HSM. HSM is also widely used to screen cocrystals, excipients and polymers for solid dispersions. With the advancements in research methodologies, it is now possible to use HSM in conjunction with other characterization techniques such as Fourier transform infrared spectroscopy (FTIR), DSC, Raman spectroscopy, scanning electron microscopy (SEM) which may have additional benefits over traditional characterization techniques for rapid and comprehensive solid state characterization.

• The Journal of the Petrological Society of Korea
• /
• v.9 no.2
• /
• pp.99-118
• /
• 2000

The variation of Na(A), K, Na(M4), A l O and Al(VI)+Fe3++Ti+Cr in the zonal amphiboles from the amphibolites of the Hwanggangri area indicates that the tschermakite-, edenite- and glaucophane substitutions are higher in the rim than in the core, in which actinolite changes to hornblende with going outward from core to rim. The contents of substitutional elements of hornblende~ of three samples@l29-2, M76-2, M78), which include diopside and greenish brown hornblende and are thought to represent the highest metamorphic grade, are lower than those of rim homblendes of the lower metamorphic grade and are higher than those of core actinolite that they conform to the middle domain in those of the whole amphiboles. Considerations about the origin of zonal amphiboles are as follows. Firstly, two samples(R102-1, R210-9) have the same amphibole composition like core is actinolitic hornblende, and rim is magnesian hastingsite although plagioclases such as albite(R102-1) and labradorite (R210-9) show the wide compositional difference. It is impossible to produce both albite and labradorite by one metamorphic event. Judging from this wide compositional difference, the existence of zonal amphiboles does not indicate the miscibility gap but is thought to be the result of the polymetamorphism. Secondly, the crystallographically sharp and gradational interfaces between actinolite and hornblende fonned in the amphibolites rgardless of the distance from the granite. In case of the samples(R210-9, M128, M130) having the sharp interface between two amphiboles, the plagioclase show the compositions produced at the low grade and the medium grade. Because such variable compositions of plagioclase indicates the overprinting of metamorphism of higher metamorphic grade than that of the formation of miscibility gap, it implies that zonal amphiboles were formed by polymetarnorphism. In case of the gradational interface between two amphiboles, this texture is also thought to be the effect of polymetamorphism from the fact that this texture mainly occur near the granite and from the consideration of the metamporphic grade. The relationship between the compositional variations of the amphiboles and the pressure types of metamorphism suggests that actinolitic core is considered to be grown by the metamorphism of medium pressure, while hornblende rim is shown to have genetic relations with the metamorphism of low pressure type.

• Korean Chemical Engineering Research
• /
• v.45 no.6
• /
• pp.638-647
• /
• 2007

In this study, we present the evaluation chart for assessing the applicability of $CO_2$ flooding method to oil reservoirs. The evaluation chart consists of four categories as source availability, miscibility, applicability and injecting method of miscible flooding. The applicability of reservoir and oil in the chart has basic items of the properties such as oil gravity, viscosity, oil saturation, reservoir temperature and permeability, and these are quantitatively graded. Meanwhile, for additional items of $CO_2$ purity, reservoir thickness and formation dip, they are graded as "highmediumlow". In the case of evaluating the injection method of either continuous injection or WAG ($CO_2$), the qualitative decision will be made according to formation dip, vertical permeability, reservoir thickness, etc. The recommended score in the chart was assigned by utilizing 51 oil producing fields which $CO_2$ flooding is successfully being applied. The evaluation chart developed in this work has been applied to the Captain oil producing field located in Scotland as well as to the Onado oil field of Venezuela, which Korean oil companies have participated in. For the Captain field, the reservoir quality in terms of permeability and porosity is considered to be very excellent to flow the oil. The oil in captain field contains heavier component of $C_{21+}$ as 54%. Therefore, this heavy oil could be immiscibly displaced, hence the evaluating result with the basis of immiscible criteria shows that $CO_2$ immiscible flooding in this field could be properly applied. In the case of Onado oil producing field, since the estimated minimum miscibility pressure is lower than the reservoir pressure, it was assessed that the Onado field would be efficiently conducted for $CO_2$ miscible flooding.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.7
• /
• pp.4081-4086
• /
• 2014

Cellulose acetate butyrate (CAB) is a biodegradable resin with excellent optical properties, but it is difficult to apply film process. In this study, an attempt was made to improve the processability of CAB using polyactic acid and the mechanical properties using an impact modifier. Polylacitc acid (PLA)/Cellulose acetate butyrate (CAB) blends with an impact modifier were prepared using a twin screw extruder. The temperature range was $140^{\circ}C$ to $200^{\circ}C$, and the screw speed was fixed to 200 rpm. To evaluate the miscibility of impact modified CAB/PLA, the glass transition behavior and morphology were observed by DSC and FE-SEM. The mechanical properties were investigated by dynamic mechanical analysis (DMA) and a Universal Testing Machine (UTM). In addition, the effect of an impact modifier in the polymer matrix was determined using a notched Izod impact strength tester. Finally, the PLA/CAB/impact modifier 75/25/10 ratio was found to be a compatible system. In the 10wt.% impact modifier, the sample had a 4 times higher izod impact strength than the non-toughening composition.

• Applied Chemistry for Engineering
• /
• v.20 no.4
• /
• pp.375-380
• /
• 2009

Polyepichlorohydrin rubber was treated with sodium azide (Na$N_3$) to replace its chlorine by azide ($N_3$). Then, the azidated polyepichlorohydrin rubber (Az-PECH) was blended with thermoplastic styrene-acrylonitrile copolymer with the rubber/plastic ratio of 80/20, 70/30 and 60/40 (wt/wt). The miscibility, mechanical and dynamic mechanical properties as well as elastic recovery properties of the blends were evaluated by DMA (Dynamic Mechanical Analyzer) and tensile tests. When azidation level in azidated PECH was upto 50%, the blends exhibited excellent miscibility, manifested by a single $T_g$, and fairly good elastic recovery. When azidation level was 75%, the blends showed phase separation. The miscible Az-PECH/SAN blends exhibited typical thermoplastic elastomer like properties, ie. melt processibility and high extensibility as well as good elastic recovery rate. It was also observed from combustion test that higher energy is released with the increase in the azidation level of the Az-PECH in the blends.