• Journal of Soil and Groundwater Environment
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• v.16 no.4
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• pp.1-9
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• 2011

Bentonite has been generally used as vertical cutoff barrier material and reported to have several problems regarding its low workability, drying shrinkage cracking by particle cohesion, and ineffective waterproof ability under sea water condition. In this study, the particle sealant, the furnace slag coated by the mixture of bentonite, sepiolite and guargum, was developed to compensate these weak points and the hydraulic conductivity of the particle sealant was evaluated. Drying shrinkage cracking and swelling index was estimated to find the optimal mixing ratio of bentonite, sepiolite and guargum. The hydraulic conductivity of the particle sealants having different amount of sealant (bentonite-sepioliteguargum mixture) coating the furnace slag was estimated using the rigid wall permeameter and flexible wall permeameter. The results showed that drying shrinkage cracking was not found in the bentonite-sepiolite mixture with 20% sepiolite contents and the results from free swelling tests for the sealant having 1 : 0.025, 1 : 0.05 and 1 : 0.075 of weight ratios of bentonite-sepiolite mixture and guargum under simulated sea water condition were higher than those for the bentonitesepiolite mixture without guargum under tap water condition. These three sealants were coated on the furnace slag with 50% and 60% of sealant in the particle sealant and the hydraulic conductivity was estimated. In the cases of the particle sealants having 20% sepiolite in the bentonite-sepiolite mixture and 1 : 0.075 weight ratio of the bentonite-sepiolite mixture and guargum, the hydraulic conductivity from the rigid wall permeameter was below $1.0{\times}10^{-7}$ cm/sec under simulated sea water condition. The hydraulic conductivity of the particle sealant having $1.0{\times}10^{-6}$~$1.0{\times}10^{-7}$ cm/sec by the rigid wall permeameter was estimated using the flexible wall permeameter and found to be below $1.0{\times}10^{-7}$ cm/sec.

• Journal of Pharmaceutical Investigation
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• v.19 no.1
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• pp.29-37
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• 1989

For the prevention of the aggregation during microencapsulation, the effects and role of polyisobutylene(PIB), as a protective colloid, were studied. The effects of sealant treatment on the microencapsulation were studied. Methyldopa was microencapsulated with ethylcellulose (EC) by polymer deposition from cyclohexane by temperature change using PIB. The EC-microencapsulated methyldopa was sealed with spermaceti. The dissolution of methyldopa was influenced by the drug to wall ratio. When PIB was used, low aggregation of microcapsules occurred and the surface was smooth with a few pores. Treatment of microcapsules with spermaceti retarded the release of methyldopa, the release being affected by the percentage of sealant used and the particle size of the product.

• Transactions of the Korean hydrogen and new energy society
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• v.5 no.1
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• pp.51-57
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• 1994

Compaction techniques of hydrogen storage alloy 'powders, to solve the problems due to disintegration during the cyclic hydriding and dehydriding, by using polytetrafluoroethylene (PTFE) and silicon sealant as a polymer binder were studied. Optimum conditions of compaction were as follows. Binder content, 10 % for PTFE and 5 % for silicon sealant ; particle size of alloy powders, $-25{\mu}m$ ; compacting pressure, $4ton/cm^2$. Compacts obtained were easily activated and had a good strength even after 30 cycles of hydriding and dehydriding. PTFE added compacts showed very good rate capability, however, in the silicon added compacts hydrogen absorption rate was somewhat slow because of higher elasticity and adhesiveness of the binder.

• Corrosion Science and Technology
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• v.21 no.1
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• pp.68-76
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• 2022

Several technologies are employed to protect substrates from corrosion and erosion damage. In particular, arc thermal spray coating technology is widely used as anti-corrosive technology for steel and concrete structures and is applied to offshore plants and petrochemical and drilling facilities. In this investigation, solid particle impingement erosion experiments were performed on an arc thermal spraying-coated specimen using 85% Al-14% Zn-1% Zr wire rod in KR-RA steel. This study investigated the effect of fluorosilicone sealing on the erosion resistance characteristics of the thermal spray coating layer. The erosion rates of the thermal spray-coated and sealed specimens were 4.1×10^-4 and 8.5×10^-4, respectively. At the beginning of the experiment, the fluorosilicone sealant was almost destroyed by the impact of the solid particles. The destruction time for the coating layer was 10 minutes for the thermal spray-coated specimen and 13 minutes for the sealed specimens, indicating that the sealed specimens had better erosion resistance characteristics to solid particle impingement.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.89-94
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• 2019

Glass base sealant is required as a ceramic-ceramic joining material between α-alumina insulation cap and β-alumina electrolyte tube in the development of NaS battery cell package for electrical energy storage system. The fabrication of glass frit by thermal quenching method, phase analysis, particle size analysis, coefficient of thermal expansion and surface roughness according to the glass compositions were analyzed for the fabrication of glass sealing paste for ceramic-ceramic joining. Also, a new evaluation method of the adhesion strength of glass sealant at the small area in ceramic-ceramic joining component was proposed using conventional Dage bond tester that was used to measure the adhesion of solder ball joint.

• YAKHAK HOEJI
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• v.32 no.1
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• pp.26-39
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• 1988

Eudragit $RS^{\circledR}$ polymer was used as a wall material for the microencapsulation of aspirin by a phase separation method from chloroform-cyclohexane system with 5% polyisobutylene (PIB) in cyclohexane, and microcapsules obtained were evaluated by particle size analysis, scanning electron microscopy (SEM), drug release and drug stability test. With PIB as a coacervation inducing agent, smooth and tight microcapsules with less aggregation were obtained. Below 1 : 0.3 core-wall ratio, it was possible to coat individual particle. Variation of production conditions showed that increasing the proportion of wall material, particle size and wall thickness of microcapsules and the concentration of paraffin wax in cyclohexane as a sealant sustained drug release rates effectively. SEM confirmed that larger microcapsules after drug release did not rupture into smaller particles but contained a few small pores on the surface. Aspirin release from Eudragit $RS^{\circledR}$ coated microcapsules was independent of the pH of medium, and the mechanism of drug release from non-sealed and sealed microcapsules appeared to fit Higuchi matrix model kinetics. Aspirin in the mixture of aspirin microcapsules and sodium bicarbonate was by far more stable than that in the mixture of pure aspirin and sodium bicarbonate.

• Journal of Pharmaceutical Investigation
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• v.21 no.4
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• pp.253-262
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• 1991

Microencapsulation of sodium ascorbate with cellulose acetate phthalate(CAP) by coacervation/ phase separation method were carried out. Various factors affecting microencapsulation, i.e., surfactant concentration. CAP concentration, stirring speed and treatment of spermaceti as a sealing agent were studied. Dissolution rate. particle size distribution, surface feature and stability test were investigated. CAP microcapsules prepared using 0.5% span 80 as a surfactant showed smooth and round surfaces. The release of sodium ascorbate was retarded by microencapsulation with CAP and by sealant treatment with spermaceti. When triturated with sodium bicarbonate, CAP microcapsules were more stable than unencapsulated sodium ascorbate under various RH conditions at $37^{\circ}C$.

• Journal of the Korea Convergence Society
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• v.9 no.12
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• pp.99-106
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• 2018

The modifier proposed in this research is for enhancing the affinity of the glass component with the high polymer resin and the molecular weight. The particle packing, tensile strength and shielding performance of the shielding sheet made of the tungsten oxide were evaluated. The best effect can be obtained when 20% of the modifier PMMA used to improve the shielding performance and maintain the affinity and strength with the sealant is mixed. The fusion of the materials presented in this study and the mass production of the shielding sheet through the modifier are possible and will contribute to the production of lightweight shielding sheets in the future.