• Polymer(Korea)
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• v.24 no.6
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• pp.744-750
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• 2000

Oil gelling agent was synthesized with PPG, PTMG and TDI at 7$0^{\circ}C$ for 4hours. PPGs and PTMGs having various average molecular weights (M$_{n}$: 1000, 2000, 3000) were employed to investigate the ratio of oil gelation and water gelation. As M$_{n}$ of PPG, in result, was decreased from 3000 to 1000, the ratio of oil gelation was increased from 130% to 290% for PPG and from 250% to 310% for PTMG. Ratio of oil gelation was increased approximately two times when EG was added. As the amount of hydrophilic compound in the prepolymer was increased, ratio of oil gelation was increased from 290% to 1120% for PPG and increased from 310% to 1310% for PTMG, due to the increased dispersion of prepolymer in the water/oil mixture.ure.

• Journal of Adhesion and Interface
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• v.3 no.2
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• pp.1-8
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• 2002

Polyurethane NCO prepolymers were synthesized with the polyols such as PTMG, GP and the isocyanate such as TDI at $40^{\circ}C$ for 8.5 minutes. As average molecular weights (${\bar{M_n}}$: 1000, 2000, 3000, 4000) of PTMG, and GP were decreased from 4000 to 1000, ratio of oil gelation increased from 298%, to 440%, for Bunker B. When oil and water were emulsified, the ratio of gelation was increased approximately two times. Ratio of gelation for emulsive Bunker B was increased from 402% to 910%, for PTMG1000 and increased from 440%, W 958% for GPI1000. Ratio of oil gelation for emulsive Bunk C which has higher viscosity than Bunker B was measured w 923% for PTMG1000 made with chain extender, i.e. EG, and measured to 1098% for GP1000. The gel made from GP which has three functional group showed soft and strong characteristic, as a result, it can be removed easily from oil spilled ocean.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.359-365
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• 1999

We have evaluated the performance and some physical properties of 25 automotive engine oils (21 domestic and 5 imported products) which are purchased on the market to verify the API(American Petroleum Institute) or ILSAC(International Lubricant Standardization and Approval Committee) certification marks attached on the products and to determine the necessity of the quality control of the engine oils on the market. 12 test items are chosen according to API engine oil specification, which are flash point, pour point, cold cranking simulator apparent viscosity, pumping viscosity, gelation index, HTHS(High Temperature High Shear viscosity), foam, high temperature foam, filterability, volatility, high temperature deposit(TEOST), phosphorus content. We have found one product which did not meet the API specification on gelation index, one on HTHS, four on foam, and one on volatility, which implies that the quality control system is in need to check the fidelity of the certification marks attached on the engine oils being marketed. In addition, this works raises the necessity of the upgrade of the present Korean engine oil specification.

• Macromolecular Research
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• v.14 no.3
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• pp.365-372
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• 2006

Poly[styrene-b-(ethylene-co-butylene)-b-styrene](SEBS) triblock copolymer was studied by dissolving the ethylene butylene midblock in selective hydrocarbon oils. These oils differ in their aromatic, paraffinic and naphthenic content. Dynamic rheological studies showed that the storage modulus (G') exceeded the loss modulus (G') for all the gels over the entire range of frequency, thereby confirming them as physical gels. However, the behavior of G' and G' as a function of frequency depended primarily on the oil type. The gelation melting temperature decreased drastically with increased oil aromaticity. Small angle X-ray scattering studies revealed that the maximum interdomain interference shifted to a higher angle depending on the composition and type of hydrocarbon oil.

• Polymer(Korea)
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• v.29 no.4
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• pp.369-374
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• 2005

In this work, the calcium alginate microcapsules containing lemon oil were prepared by emulsification-internal gelation and their potential use as aromatherapy was examined by the controlled release system. The lemon oil encapsulated in the alginate was successfully observed by Fourier transform (FT-IR) spectroscopy and differential scanning calorimeter (DSC) measurements. Analysis of the diameters and shapes of microcapsules was conducted by scanning electron microscopy (SEM). The mean diameters ranging from 4 to 7 um and encapsulation yield ranging from 50 to $85\%$ were obtained. The controlled release of the lemon oil at $37^{circ}$ was demonstrated by the infrared moisture determination (IMDB). It was found that the amount of released lemon oil decreased with increasing concentrations of alginate and $CaCl_2$ due to the higher the cross-linking density of the capsules prepared. The oil release from the capsule was measured as a function of physical force. We confirmed that the external factor could control the collapse of capsule wall and the release rate.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.94-100
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• 2003

Gel-like compounds containing flammable solvents were prepared to use fur cleaning agents in field of innovative industries and general purposes. And experiments were conducted to improve the defects of liquified flammable solvents from the view point of safety and health hazards. Flammable solvents used in this study were several single component flammable solvents(turpentine oil, N-methyl-2-pyrrolidone(NMP), d-limonene) and multi component flammable solvent(gasoline and ethanol). For gelation of flammable solvents, commercially Known as Aerosil(equation omitted) 200 fumed silica and triethanolamine(TEA) were used as gelation agent dispersant. The analyses on properties of gel-like compounds was studied by gelation and viscosity test pH test, volatility test and differential scanning calorimetry(DSC) measurement. The experimental results indicate that gel-like compounds containing flammable solvents have pH stability, high viscosity, volatile organic compounds(VOC) control by the decrease of volatility and odor component generation, fluidity control etc. From the experimental values, it can be predicted that the safety in the working place is improved by manufacturing flammable solvents into gel-like compounds.

• Bulletin of Food Technology
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• v.24 no.3
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• pp.377-387
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• 2011

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.86-91
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• 2006

Oil spills caused by the accidents have been occurred from house and factory waste, grounded tanker, the rupture of storage tank and oil pipelines, the deterioration of various industrial facilities, etc. Many oil spills result in contamination of shorelines and workplace. Fire and explosion may happen from these spills. There are several technologies used for clean-up application, which include use of oil dispersing agents, absorbents, solidifiers, booms and skimmers by physical, chemical, and biological methods. Methods for oil spill clean-up operation are classified into the absorption type, gel type and self-swelling type. Porous materials with oil absorptive properties are classified into micropore, mesopore, and macropore depending on their pore sizes. Recently, new porous materials with smaller size have been developed, but the selective oil absorption in water-in-oil interface demonstrates the macro pore size. In this study oil absorption effects were evaluated using the organic porous materials with a complex function of gel type and swelling type. Samples were subjected to analysis by FT-IR spectroscopy and were characterized in terms of gel formation and morphologies. Oil sorption capacity, pressure retention force and gel strength were also measured. From these results, the physicochemical reactivity before and after gelation was verified and the industrial applications of clean-up operation were suggested.

• Clean Technology
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• v.23 no.3
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• pp.270-278
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• 2017

This study introduces a method to easily fabricate highly monodisperse pectin hydrogel microfibers in a microfluidic device by using partial gelation. The hydrodynamic parameters between the pectin aqueous solution and the calcium ions containing oil solution are precisely controlled to form a stable elongation flow of the pectin aqueous solution, and partial gelation of the pectin aqueous solution is performed by the chelating of the calcium ions at the interface between the two phases. The partially gelled pectin aqueous solution is phase-separated from the oil solution in an aqueous calcium chloride solution outside the microfluidic device and is completely gelled to produce monodisperse pectin hydrogel microfibers. The thickness of the pectin hydrogel microfiber is controlled in a reproducible manner by controlling the volumetric flow rate of the initially injected pectin aqueous solution. The pectin hydrogel microfibers were 200 to 500 micrometers in diameter and had a coefficient of variation below 5% under all thickness conditions, indicating that the pectin hydrogel microfibers produced by partial gelation are highly monodisperse. In addition, biomaterials can be immobilized to the pectin hydrogel microfibers produced by a single process, demonstrating the possibility that our pectin hydrogel microfiber can be used as carriers for biomaterials or tissue engineering.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.370-370
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• 2006

Thermoplastic elastomer gels, which has molecular networks composed of a microphase-separated multiblock copolymer swollen to a large extent by a low volatility mid-block selective solvent such as white oil have various applications. In this particular study, the effect of several network-forming nanoscale fillers such as two different graphite particles and carbon nanotube on the properties of TPE gels prepared from a microphaseordered poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) triblock copolymer with an EB compatible white oil was studied. The linear viscoelastic behavior, sol-gel transition, x-ray diffraction and mechanical properties were discussed. The properties of thermoplastic elastomer gels hybrid with graphite prepared by mixing Poly(styrene-b-ethylene-co-butylene)-b-styrene) with paraffin oil and different amount of expandable graphite were found to increase the mechanical properties at only lower graphite concentration but tends to decrease when paraffin oil/SEBS ratio is lower. The gelation temperature is the same for all TPE gels with different amounts of graphite. Both storage (G') modulus loss (G") modulus of TPE gels slightly increase with addition of graphite.