• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1086-1093
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• 1998

The antimicrobial effect of mixed solutions of grapefruit seed extract(250ppm) and ascorbic acid(1%) on the spoilage microorganisms such as Staphylococcus epidermis, Escherichia coli, Pseudomonas syringae, Candida albicans and Corynebacterium xerosis isolated from the spoiled soybean sprouts were investigated. Cell wall and membrane were partially destroyed and the contents of the destroyed cell were exuded after treatment. Packages with 30 m cast polypropylene(CPP), 16 m polyolefin(RD 106) and 10 m high density polyethylene(HDPE) were applied for soybean sprouts dipped in mixed solutions respectively. Oxygen and carbon dioxide concentration inside packages were dependent on the kind of films during storage at 5oC. The antimicrobial activity of mixed solutions was maintained for 5 days at CPP package. Package with HDPE showed a severe browning than the others after 5 days. Ascorbic acid content of mixed solution treatment was higher than that of control for each package.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.12-17
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• 1996

The structure formation by liquid-liquid(L-L) phase separation coupled with crystallization in isotactic polypropylene(i-PP). solutioos was investigated by a temperature jump experiment. A series of dialkyl phthalates with a different number of carbon atoms in the alkyl chain was used to control the interaction between polymer and solvent. Various thermal quench conditions were applied to the i-PP solutions to control systematically L-L phase separation and crystallization. A slow crystallizatina elongates the liquid droplets in the radial direction of a spherulite. A rapid crystallization under the deep quench locks-in the growth of L-L phase separation. These results indicate that the extent of L-L phase separation which exists below melting point can be successfully controlled through the proper selection of solvent and thermal conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1394-1397
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• 2003

The first thing in developing injection molding and extrusion with microcellular foaming process is to get a grip on one phase state's rheology of gas and polymer solution. Understanding rheology is essential to design mold or die. and it is so important to control the condition of process. Also, this data is got the utmost out of simulation carrying out. In this paper, we will see the measurement of rheology in one phase that mixed polypropylene which contains talc with carbon dioxide of super critical fluid state, and will compare its result with the simulation result.

• Membrane Journal
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• v.22 no.5
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• pp.359-368
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• 2012

For hybrid water treatment of high turbidity water, we used the hybrid module that was composed of photocatalyst packing between tubular membrane outside and module inside. Photocatalyst was PP (polypropylene) bead coated with $TiO_2$ powder by CVD (chemical vapor deposition) process. Water back-flushing of 10 sec was performed per every period of 10 min to minimize membrane fouling for modified solution was prepared with humic acid and kaolin. Resistance of membrane fouling ($R_f$) decreased as humic acid concentration changed from 10 mg/L to 2 mg/L, and finally the highest total permeate volume ($V_T$) could be obtained at 2 mg/L, which was the same with the previous results. Then, treatment efficiencies of turbidity and humic acid were above 98.9% and 88.7%, respectively. As results of treatment portions of UF, UF + $TiO_2$, and UF + $TiO_2$ + UV processes, turbidity was treated little by photocatalyst adsorption, and photo-oxidation. However, treatment portions of humic acid by adsorption and photo-oxidation were 2.5% and 12.3%, respectively. Compared with the previous results, treatment portions of humic acid by adsorption and photo-oxidation were different depending on membrane material and pore size. As simplified the process, the membrane fouling resistance after 180 minutes' operation ($R_{f,180}$) increased and the final permeate flux decreased a little.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.528-535
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• 2016

Two types of oleophilic acrylic prepolymers were prepared by the solution copolymerization of either ethyl acrylate (EA) or lauryl acrylate (LA) with hydroxy ethyl acrylate (HEA). For the formation of oil-absorbent materials, a mixed solution of the prepolymer and hexamethylene diisocyanate (HDI) as a cross-linker in toluene was applied to polypropylene knit velvet fabric through the conventional pad-dry-cure procedure. The gel fraction of the crosslinked resin, EA-HEA-HDI, increased with increasing feed ratio of HEA to total acrylate or HDI concentration. The oil absorbancy and retention ratio of the prepared materials were compared according to the add-on ratio of resin to fabric, and were assessed with n-decane, toluene, soybean oil, lubricant and bunker C oil as test oils. The optimal oil absorbancy of the materials were observed at around 6% of the add-on ratio for all these oils except for soybean oil. On the other hand, the oil retention ratio increased as the add-on ratio increased. Futhermore, heavier and more viscous oil generally showed higher oil retention ratios. In addition, the oil absorbancy of the materials treated with LA-HEA-HDI resin was higher than that treated with EA-HEA-HDI resin, which showed that the acrylic resins are more absorptive with increasing length of their side alkyl chain.

• Food Science and Preservation
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• v.18 no.4
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• pp.475-480
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• 2011

This papers were studies the effects of high $CO_2$ concentration pretreatment and ascorbic acid on the browning of fresh-cut apples. The prepared samples were dipped in 1% (w/v) ascorbic acid solution (AA). Fresh-cut apples (3 pieces) were packed in polypropylene bags (0.03 mm, $20{\times}15$ cm), and stored at $10^{\circ}C$ for 16 days. AA-treated samples showed higher L value than those of non-treated and control (dipped in water without $CO_2$ pretreatment), while non-treated samples showed higher hardness than AA-treated sample. Total soluble solids, pH, titratable acidity were not affected by high $CO_2$ pretreatment and AA treatment. These result shows high $CO_2$ concentration pretreatment with dipping in 1% ascorbic acid solution (AA) has an effects on controlling enzymatic browning during the storage of fresh-cut 'Fuji' apples.

• Journal of Environmental Science International
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• v.22 no.2
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• pp.243-249
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• 2013

Fibers of microbial polyesters, poly(3-hydroxy butyrate) (PHB) and poly(3-hydroxy butyrate-co-3-hydroxy valerate) (HB-co-HV) were prepared by electrospinning method. The obtained fibers were evaluated by differential scanning calorimetry, scanning electron microscopy, and oil absorption. The formation of fibers was strongly dependent on a concentration of solution. At a low concentration, the fibers contained beads which is from aggregation of polymer due to short evaporation time. The fine fibers with $2-5{\mu}m$ diameter were obtained at 20 wt% concentration. The contact angle measurement showed that the fiber had higher water contact angle than the film due to the lotus-like effect. Oil absorbency showed that the fiber had higher than the film. Specially, the HB-co-HV fiber which was spinned from 20 wt% absorbed 65% oil which is much higher than that of a normal polypropylene-based oil paper.

• Textile Coloration and Finishing
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• v.23 no.3
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• pp.210-218
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• 2011

The structure of kapok fiber was characterized using FTIR and $^{13}C$-NMR spectrometers, elemental analyzer, x-ray diffractometer, SEM and IMT I-Solution ver 7.5. The kapok has a hollow tube shape and is composed of cellulose I with crystallinity of 47.95%. To develop novel oil-sorbent materials necessary to avoid the environmental pollution by spilled oil, the oil absorption capacity of various fibers such as kapok, polypropylene(PP), acryl, bamboo, cotton, rayon and wool fibers is compared in this study. The kapok fiber had the highest oil absorption capacity among the fibers and its water absorption capacity was the least. The kapok fiber selectively absorbed significant amounts of oils (43g/g of fiber for kerosene, 65g/g of fiber for soybean oil), which might be due to higher hydrophobicity of the kapok fiber, suggesting that kapok fiber may have high potential as excellent oil-absorbent materials.

• Membrane and Water Treatment
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• v.7 no.5
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• pp.463-476
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• 2016

In this study, application of polypropylene hollow fiber membrane contactors for $CO_2$ removal from water in liquid-liquid extraction (LLE) mode was simulated. For this purpose, a steady state 2D mathematical model was developed. In this model axial and radial diffusion was considered to $CO_2$ permeation through the hollow fibers. $CO_2$ laden water is fed at a constant flow rate into the lumen side, permeated through the pores of membrane and at the end of this process, $CO_2$ solution in the lumen side was extracted by means of aqueous diethanolamine (DEA) and chemical reaction. The simulation results were validated with the experimental data and it was found a good agreement between them, which confirmed the reliability of the proposed model. Both simulation and experimental results confirmed the reduction in the percentage of $CO_2$ removal by increment of feed flow rate.

• Corrosion Science and Technology
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• v.12 no.6
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• pp.295-303
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• 2013

Silane surface treatments have been developed as an alternative for toxic and carcinogenic chromate-based treatments for years. It is consistently observed that ultra-thin films offer excellent corrosion protection as well as paint adhesion to metals. The silane performance is comparable to, or in some cases better than, that of chromate layers. Based on the tetra-ethylorthosilicate(TEOS) and methlyl trieethoxysilane(MTES), inorganic sol was synthesized and formed hybrid networks with $SiO_2$ nano particle and polypropylene glycol(PPG) on Zn alloyed steel surface. According to SST results, addition of 10nm and 50nm $SiO_2$ nanoparticle in synthesized solution improved anti-corrosion property by its shear stress relaxation effect during curing process. Also, SST results were shown that anti-corrosive property was affected by the amounts of organic compounds.