• Analytical Science and Technology
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• v.19 no.2
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• pp.181-187
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• 2006

This study was carried to survey the removal characteristics of BPA using coagulation process by PAC and PAHCS. BPA removal for PAC and PAHCS was 20.4 with 8.7 Al mg/L and 6.8 Al mg/L, respectively. Removal of BPA was lower than $UV_{254}$ and DOC but removal characteristics were similar. BPA removal for PAC and PAHCS was most high in pH 6.5 and 7.0 respectively. The time for removal by mixing time was 40 min in PAC and 30 min in PAHCS. When powdered activated carbon 50 mg/L was added in coagulation process, a high remove of BPA (61%) was noticed. Specially BPA was highly increase powdered activated carbon 5 mg/L alone. These results will be appliable in the conventional water treatment plants for improvement of water treatment system.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.235-238
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• 2005

Sulfonated poly(ether sulfone) copolymers (PESs) were synthesized using hydroquinone 2-potassium sulfonate (HPS) with other monomers (bisphenol A and 4-fluorophenyl sulfone). PESs with different $mole\%$ of hydrophilic group were prepared by changing the mole ratio of HPS in the polymerization reaction. The chemical structure and the thermal stability of these polymers were characterized by using $^1H-NMR$, FT-IR and TGA techniques. The PES 60 membrane, which has $60 mole\%$ of HPS unit in the polymer backbone, has a proton conductivity of 0.091 S/cm and good insolubility in boiling water. The TGA showed that PES 60 was stable up to $272^{\circ}C$ with a char yield of about $29\%\;at\;900^{\circ}C\;under\;N_2$ atmosphere. To investigate the single cell performance, the catalyst coated PES 60 membrane was used and a single cell test was carried out using $H_2/O_2$ gases as fuel and oxidant at various temperatures. We observed that the cell performance was enhanced by increasing the cell temperature. A current density of $1400 mA/cm^2$ at 0.60 V was obtained at $70^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.639-648
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• 2010

The optimal conditions for the analysis of BPA by HPLC-MS/MS was investigated and the ultrasound degradation capacity of the BPA, with the goal to establish the proper directions for analyzing infinitesimal quantities of BPA by HPLC-MS/MS was examined. The MDL and LOQ of BPA analyzed by HPLC-MS/MS were measured 0.13 nM and 1.3 nM respectively, its sensitivity about 620 and 32 times greater than HPLC-UV (MDL: 81.1 nM, LOQ: 811 nM) and FLD (MDL: 4.6 nM, LOQ: 46 nM). In other words, the new method enables the analysis of BPA with the accuracy up to one 1,180th of the amount specified in U.S. EPA guideline for drinking water. Degradation rate of BPA by ultrasound measured over 95% under 580 kHz and 1000 kHz frequency within 30 minutes of treatment, whereas the rate showed some decrease at 28 kHz frequency. At 580 kHz of ultrasound has proven to be the most effective among others at degradation rate and $k_1$ value, so we concluded that this frequency of ultrasound creates hospitable condition for the combined process of degradation by pyrolysis and oxidization. With the addition of 0.01 mM of $CCl_4$, BPA with the initial concentration of 1 ${\mu}M$ was degraded by more than 98% within 30 minutes, the $k_1$ value measured 5 minutes and 30 minutes into the experiment both showed increases by 1.4 and 1.1 times, respectively, compared with BPA without $CCl_4$. It is also found that the main degradation mechanism of BPA by ultrasound is oxidization process by OH radical, based on the fact that the addition of 10 mM of t-BuOH decreased the rate of BPA degradation by around 60%. However, 33% of BPA degradation rate obtained with the addition of t-BuOH implies further degradation done by pyrolysis or other sorts of radical beside OH radical.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.276-283
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• 2008

To provide the research strategy for protection of children's health from hazardous chemical, we reviewed the hazardous chemicals can be exposed through maternity, children's life style and living environment. Recently, diseases related with children's living condition were focused as asthma, atopy, childhood developmental disability, congenital malformations and obesity. Children can be exposed to hazardous chemicals through an ambient air, water, soil, food, toys and other factors such as floor dust. Also children's health was deeply related with a wrong life style and neglectful caring by a lack of knowledge and information of harmful ones at parents and child care center's nursers. According to the previous study, the chemical risk factor of children's health were identified as inorganic arsenic, bisphenol A, 2,4-D, dichlorvos, methylmercury, PCBs, pesticide, phthalates, PFOA/PFOS, vinyl chloride, et al. Domestic studies for identification of causality between children exposure to chemicals and resulted hazardous effects were not implemented. The confirmation of chemical risk factors through simultaneously performing toxicological analysis, human effect study, environmental/human monitoring, and risk assessment is needed for good risk management. And also, inter-agency collaboration and sharing information can support confirming scientific evidence and good decision making.

• Journal of the Korean Chemical Society
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• v.19 no.4
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• pp.269-279
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• 1975

Photosensitive properties of naphthoquinone-1,2-diazide-5-sulfonyl esters (PGND, BEND and PVAND) of polyglyceryl phthalate(PG), bisphenol A-epichlorohydrin condensate(BE) and polyvinyl alcohol(PVA) were investigated by the change of solubility before and after exposing to light. Various samples coated on glass or quartz plates were exposed to light under various conditions and steeped in aqueous alkali solution, and then the yield of residual film(W/W0) was determined. The yield of residual film, which was closely related to the sensitivity of the film, was affected by the degree of polymerization of the backbone resin, sensitizers and their concentration. In polymer homologs, the sensitivity was dependent on the degree of polymerization(the higher, the better). And also, it was most effective when 5 % of sensitizers to esters was used. The minimum exposed time was 0.6 min. for PGND-1, 1.0 min. for BEND-1, and 3.0 min. for PVAND-1. Most effective sensitizers for PGND, BEND and PVAND among those used here were benzanthrone, 5-nitroacenaphthene and picramide, respectively. The spectral sensitivities of PGND, BEND and PVAND were examined by comparing their spectrograms with UV-spectra in a solid state. Also, the sensitization and spectral sensitivity of the above polymers were studied. All the polymers containing the sensitizers showed optical sensitization. From the fact that in either case of sensitized or unsensitized sample, the ranges of absorption-maximum wave length were almost consistent with sensitivity maximum wave length, it was proved that the light absorbed by a sample served efficiently for photochemical reactions. Benzanthrone was found to be an excellent sensitizer for PGND.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.627-638
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• 1992

PPG and BPA-type polyurethane prepolymers(NCO terminated) were obtained from bisphenol A and four types of PPG, having different molecular weight and numbers of functional groups. PPG and BPA-type polyurethane dimethacrylates were synthesized by reacting PPG and BPA-type polurethane prepolymer with 2-HEMA respectively. PPG-type polyurethane dimethacrylates were formulated with initiator(CHP), inhibitor(hydroquinone) and reactive diluent(TEGDMA). The effect of formulation on the torque changes was studied. Four kinds of PPG-type polyurethane dimethacrylates, having different molecular weight and numbers of functional group, were formulated with the same amount of CHP, TEGDMA and hydroquinone. The effects of the molecular weight of PPG-type polyurethane dimethacrylate and functional group numbers of PPG-type polyurethane dimethacrylates on the torque were investigated. These results showed that the torque of PPG-type polyurethane dimethacrylates, having same numbers of functional group, increased with decreasing molecular weight of dimethacrylates and torque of PPG-type polyurethane dimethacrylate, having similar molecular weight, was increased with increasing the number of fuctional group. The glass-transition temperature(Tg) of gels obtained by thermosetting cure for the four kinds of PPG-type polyurethane dimethacrylates were measured by DSC and molecular weights between cross-links(Mc) were calculated from Tg changes.

• Korean Journal of Ecology and Environment
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• v.38 no.1 s.110
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• pp.11-17
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• 2005

Egg masses of C. plumosus were collected from Jungnang Stream in Seoul and reared in an incubator chamber. The larvae of C. plumosus were treated with potential endocrine disruption chemicals (EDCs) such as Diethylhexyl phthalate (DEHP), Bisphenol A (BPA) and Tebufenozide, and the effects of morphological abnormalities were observed. The deformities of the mentum following exposure to EDCs showed the smooth/round tooth, the loss of ${\ge}$1 tooth, reduced median lateral teeth (MLT) and light brown color. The incidence rates of the mentum deformity were associated with chemicals: BPA (73.7 ${\sim}$ 90.9%)>tebufenozide (57.6 ${\sim}$ 78.9%)>DEHP (46.2 ${\sim}$ 85.7%). The deformity type of the mentum showed MIX (MLT+LT, 32 ${\sim}$ 46%)>MLT (25 ${\sim}$ 34%)>LT (lateral teeth, 3 ${\sim}$ 7%). Also, the incidence of MIX type was in the order of BPA (46%)>DEHP (33%) >tebufenozide (32%), and that of MLT type showed DEHP (34%)>tebufenozide (31%)>BPA (25%). As the concentration of Tebufenozide increased, the incidence of light brown mentum was dose dependent. While the incidences of light brown mentum following exposure to BPA and DEHP were not associated with their concentrations.

• Journal of Life Science
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• v.26 no.10
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• pp.1130-1136
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• 2016

The purpose of this study was to investigate the anti-proliferative and apoptotic effects of acid extract of Gracilaria verrucosa (AEG) on RC-58T/h/SA#4 primary human prostate cancer cells. AEG significantly decreased the cell viability of prostate cancer cells in a dose-dependent manner. AEG also showed relatively low cytotoxicity on normal cell (RWPE-1). The morphology of prostate cancer cells treated with AEG was distorted to shrunken cell masses. In addition, it was revealed that AEG induced cell death as evidenced by increased formation of apoptotic body and nuclear condensation. Furthermore, AEG clearly modulated the down regulation of Bcl-2 (anti-apoptotic)/Bax (pro-apoptotic) family and activated caspase-3 as an effector caspase in a dose-dependent manner. AEG inhibited cell proliferation induced by environmental hormones as a bisphenol A in a dose-dependent manner. These results indicate that AEG act as anti-proliferative effects as a potential therapeutic agent on primary human prostate cancer cells.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.2
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• pp.77-83
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• 1991

In this study the investigation were carried out on short-term breakdown characteristics of the compound material dependent on change of filler quantity, ambient temperature(room temperature~[$190[^{\circ}C$]) and kinds of voltage sources for the compound materials of Bisphenol- A epoxy resins filled with $SiO_2$ particles. As the results, obtained the dielectric breakdown strength generally decrease as increasing the quantity of filler and the distance, spacing of each's particles, decrease as increasing the quantity of filler, when the distance is less than [$7.5\mu\textrm{m}$], dielectric breakdown strength is nearly constant. In the case on AC voltage dielectric strength of filled epoxy resins is stronger than nonfilled epoxy resins on temperature region more than $130[^{\circ}C$].

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.1-2
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• 2003

While aromatic polyimides and polyamides have found widespread use as high performance polymers, the present work addressed the need for organosoluble materials through the use of a hyperbranching scheme. The $AB_2$ monomers were prepared. The $AB_2$ monomers were then polymerized via aromatic fluoride-displacement and Yamazaki reactions to afford the corresponding hydroxyl-terminated hyperbranched polyimides (HT-PAEKI) and amine-terminated hyperbranched polyamides, respectively. HT-FAEKI was then functionalized with allyl and propargyl bromides as well as epichlorohydrin to afford allyl-terminated AT-PAEKI, propargyl-terminated PT-PAEKI, and epoxy (glycidyl)-terminated ET-PAEKI, in that order. All hyperbranched poly(ether-ketone-imide)s were soluble in common organic solvents. AT-PAEKI was blended with a bisphenol-A-based bismaleimide (BFA-BMI) in various weight ratios. Thermal, rheological, and mechanical properties of these blend systems were evaluated. Two characteristic hyperbranched polyamides, which the one has para-electron donating groups to the surface amine groups and the other has para-electron withdrawing groups to the surface amine groups, were selected to compare BMI curing behaviors. The electron rich polymer displayed ordinary Michael addition type exothermic reaction, while electron deficient polymer did display unusual curing behaviors. Based on analytical data, the later system provided the strong evidences to support room temperature curing of BMI by reactive intermediates instead of reactive primary amine groups on the macromolecule surface.