• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.875-879
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• 2008

A method for the depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The effect of operation variables such as reaction time, reaction temperature, EG/PC weight ratio and the kinetic of glycolysis were studied. It was found that the polymerization reaction has two different activation energies depending on the reaction temperature. A drop in activation energy with temperature indicates that the reaction mechanism has shifted from one of a succession of elementary steps to another in the series. The maximum yield of BPA of 95.6% was achieved at reaction temperature $220^{\circ}C$ for 85min with EG/PC weight ratio 4.

• Ecology and Resilient Infrastructure
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• v.6 no.2
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• pp.128-135
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• 2019

This study evaluates the effect of dissolved effluent organic matter (SE-dEfOM) from sewage wastewater treatment plants on the adsorption and estrogenic activity of bisphenol A (BPA). Specific ultraviolet absorbance and fluorescence index analyses indicated that SE-dEfOM was mainly microbially derived non-humic substances differed from Suwannee River natural organic matter (SR-NOM) as reference. Both Langmuir and Freundlich models successfully explained the adsorption of BPA onto both SE-dEfOM and SR-NOM. Additionally, the SE-dEfOM showed higher binding capacities and affinities for BPA than those of SR-NOM, resulting in better reduction of the estrogenic activity of BPA. These findings suggest that the binding and toxicity of BPA are largely dependent on the source of organic matters.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.299.1-299
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• 2001

• Polymer(Korea)
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• v.30 no.6
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• pp.538-544
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• 2006

Two kinds of novel bifunctional methacrylated prepolymers (170-2MA and 631-2MA) which have similar structure with 2,2-bis[4- (2'-hynroxy-3'-methacryloyloxypropoxy)phenyl] propane (Bis-GMA) was synthesized for dental applications as an alternative to Bis-GMA containing bisphenol A that is doubtful as an endocrine disrupter. The organic matrices were prepared by mixing a diluent and/or a monomer with the synthesized methacrylated prepolymers. The yield, viscosity, and chemical structures of the prepolymers and the physical and methanical properties of the organic matrices were evaluated. The yields of the prepolymers synthesized through a ring-opening reaction of epoxy compound and methacrylic acid were above 90% and the viscosities of the prepolymers were much lower than that of the Bis-GMA control. From the results of $^1H-NMR$ and FTIR analyses, the chemical structures of the prepolymers were similar to that of Bis-GMA. In addition, the curing time, poly-merization shrinkage, photoconversion, polymerization depth, and compressive strength of the organic matrices formulated with 170-2MA and 631-2MA prepolymers exhibited comparable to or better than those of the existing Bis-GMA-based one. These results suggest that the novel methacrylated prepolymers which have no endocrine disrupter can be an alternative to Bis-GMA and be applicable to dental polymer materials.

• Korean Journal of Environmental Biology
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• v.20 no.2
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• pp.158-164
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• 2002

Some of synthetic chemicals can net as an endocrine disrupting substance in higher animals. Dioxins, DDT, PCBs and bisphenol A (BPA) are classified into endocrine disruptors and aye under a strict control in many countries. This research was designed to compare the clastogenic effects of BPA to those of ionizng radiation to establish the relaltive effectiveness of BPA by means of Tradescantia micronucleus assay. For the uptake of the BPA through the stems, groups of fresh cuttings of Tradescantia BNL 4430 weve placed in BPA solutions of 0 to 4 $\mu$M for 6 hours under continuous aeration. The other groups of the cuttings were irradiated with 0 to 0.5 Gy of gamma- rays. The frequencies of micronucleus showed a positive dose- response relationship in the range of 0 to 0.5 Gy, and a clear concentration-response relationship in the experimental range of BPA concentrations. By comparing the two experimental results, it is possible to estimate the BPA concentration and its equivalent radiation dose for a fixed value of MCN frequency. BPA of $ll.8\mu{M}$ can give rise to 53.3 MCN/100 tetrads, which is the same frequency induced by 25 cGy of gamma- rays. It is of biological importance that clinical symptoms start to develop after a whole body exposure to radiation higher than 25 cGy. The results indicate that the pollen mother cells are an excellent biological end- point for toxicity test of suspected endocrine disrupting chemicals such as bisphenol A, cotylphenol and nonylphenol.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.6
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• pp.689-698
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• 2007

A new technique was proposed for the determination of alkylphenols, chlorophenols and bisphenol A in korean aquatic biological samples. The alkylphenols, chlorophenols and bisphenol A in korean aquatic biological samples were extracted with acetonitrile and then acetonitrile layer was refrigerated at $-60^{\circ}C$ for 2 hours(freezing filtration method). Also, solid-phase extraction(SPE) was used to XAD-4 and subsequent conversion to isobutoxycarbonyl(isoBOC) or tert-butyldimethylsilyl(TBDMS) derivatives for sensitive analysis with gas chromatography/mass spectrometry-selected ion monitoring(GC/MS-SIM) mode. For isoBOC derivatization and TBDMS derivatization the recoveries were $70.1\sim150.6%$ and $93.8\sim108.3%$, the method detection limit(MDLs) of bisphenol A for SIM were $0.062{\mu}g/kg$ and $0.010{\mu}g/kg$, and the SIM respectively. When these methods were applied to korean aquatic biological samples, the concentrations of the 11 phenolic EDCs were $0.675\sim1.970{\mu}g/kg$.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.318-326
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• 1992

Vinylester resin was synthesized by reacting epoxy resin with MAA(methacrylic acid) at a equivalent ratio of 1.1/1.0 in the presence of N,N dimethyl benzylamine. Low molecular weight epoxy(DER 331) was used together with higher molecular weight epoxy(DER 662, DER 664) and a novolac epoxy(DEN 439), and the amount of DER 331 was not over 50% of the total epoxy components. Viscosity, cure time and mechanical properties of the vinylester resin were profoundly influenced by the quantity of reacted MAA, and the structure and molecular weight of the epoxy resin. Tensile and flexural strength appeared to be the greatest when DER 331 fraction was 30~40%.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.570-577
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• 2000

A method was presented for determination of bisphenol F(BPF), bisphenol A(BPA), bisphenol F diglycidyl ether(BFDGE) and bisphenol A diglycidyl ether(BADGE) in 3 aqueous-based food simulants (water, 4% acetic acid, 20% ethanol) by reverse-phase high performance liquid chromatography(RP-HPLC)with fluorescence detection and gas chromatography with mass selective detection(GC/MSD). All the calibration lines in the range of $5{\sim}800\;{\mu}g/L$ had correlation coefficients greater than 0.9998 and detection limits of less than $1.2\;{\mu}g$ bisphenols/L. Precision at $200\;{\mu}g/L$ was under 3.1%. Recoveries of bisphenols simultaneously spiked to aqueous food simulants exceeded 95% for BPF and BPA but about 80% for BFDGE and BADGE. However, recoveris of BFDGE and BPADGE respectively spiked increased upto 95%. Detection limits in recovery test were less than $0.40\;{\mu}g$ bisphenols/L. In migration test bisphenols were determined by RP-HPLC coupled with confirmation by GC/MSD. Can coatings of epoxy phenol, modified epoxy, epoxy ester phenol and thermoset vinyl were exposed to the 3 aqueous food simulants. BPF, BFDGE and BADGE were not detected in all the can coatings but BPA was detected in 4% acetic acid and 20% ethanol in all the can coatings except modified epoxy.

• Child Health Nursing Research
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• v.10 no.1
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• pp.108-116
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• 2004

Purpose: There has been a number of reports on elution of bisphenol-A, an endocrine disrupting chemical, from milk bottles, all concerning the potential health effect of the substance. In this study, we measured the elution of bisphenol-A from milk bottles during boiling-water sterilization, to suggest a safe sterilization method. Method: Through the survey of 200 mothers, 78.5％ of them expressed their concern on the possible harmful effect of bisphenol-A, which might be eluted from the bottles. And it was found that most mothers use boiling-water to sterilize bottles; duration of boiling bottles could be divided into three groups of 3, 5, and 10 minutes. We measured the elution of bisphenol- A from three different brands of bottles, subject to various mode of sterilization found in the survey. Result: In all the measurements, the concentration of the eluted bisphenol-A was in the range of 0.3 - 0.7 ppb, far below 2.5ppm, the level set up by Korea Food ％amp; Drug Administration(KFDA) for a potential harmful effect. Conclusion: Although trace amount of bisphenol -A can be eluted from polycarbonate milk bottles during sterilization, and bottle feeding, the amount is found to be too small to cause any health related impact for infants.

• Journal of Environmental Science International
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• v.30 no.12
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• pp.1005-1014
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• 2021

Organic contaminants can be released into water environments due to chemical accidents and exist as dissolved and non-aqueous phase liquids (NAPL). Fenton oxidation was tested for bisphenol A and nitrobenzene as model organic contaminants in dissolved and NAPL states. Fenton oxidation was successfully applied for both of the dissolved and NAPL states of the two pollutants and the results indicated that a quick treatment was needed to reduce the risk from a chemical accidents instead of carrying out oxidation after the contaminants dissolve in water. A set of Fenton reactions were tested under seawater conditions because chemical accidents often occurs in the ocean. Chloride ions act as radical scavengers and inhibit Fenton oxidation. The reaction rate is inversely proportional to salt contents and the reduced reaction rate can be compensated by increasing the quantity of the oxidizing agents. The current study showes that Fenton oxidation could be applied as a quick treatments for organic contaminant in dissolved and NAPL state organic contaminants released as a result of leaks or chemical accidents.