• Polymer(Korea)
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• v.25 no.3
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• pp.349-358
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• 2001

Silyl group-containing acrylic resins were synthesized to prepare weather resistant coatings. Acrylic copolymer was synthesized by the addition copolymerization of n-butyl methacrylate, methyl methacrylate, n-butyl acrylate and 3-methacryloxypropyl trimethoxysilane (MPTS). Acrylic copolymer were synthesized such that their $T_g$'s were adjusted to $20^{\circ}C$ and their MPTS contents were varied to 10, 20 and 30 wt%. As the content of MPTS increased, viscosity of coatings increased and thermal stability at the high temperature was improved. Coatings was prepared by blending the synthesized resins with a white pigment. The adhesion performance of coatings was superior with various substrates and their other properties were on the whole suitable. Weatherability was tested by outdoor exposure test, WOM test and QUV test. It was proved that resin with 30 wt% MPTS was suitable as the binder for weather resistant coatings.

• Journal of the Korean Chemical Society
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• v.56 no.5
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• pp.597-602
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• 2012

The copolymerization of triacetoxyvinylsilane, EGDMA (ethylene glycol dimethacrylate as a cross-linker), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), MA (methacrylic acid) was performed in the presence of AIBN (2,2'-azobisisobutyronitrile) as an initiator. Measurement of the physical properties of the resulting copolymers showed that water content, refractive index, visible ray transmittance, and tensile strength were in the range of 35.63~32.44%, 1.4382~1.4480, 89.0~92.5% and 0.346~0.674 kgf, respectively. The values of tensile strength of copolymers-containing hexamethylene diisocyanate were higher than those of the copolymers containing triacetoxyvinylsilane. From the results we came to the conclusion that the produced copolymers are suitable for the application of ophthalmic contact lens with high tensile strength, wettability and duraility.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.761-765
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• 2010

Poly (N,N-dimethylacrylamide) is very useful in various fields due to its remarkable properties, such as water solubility and biocompatibility. This study used N,N-dimethylacrylamide with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), NVP (N-vinyl-2-pyrrolidone) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Measurement of the physical properties of the copolymerized polymer showed that the water content was 36 - 42%, refractive index was 1.433 - 1.426 and visible ray transmittance 90 - 91% while the oxygen permeability showed a distribution between 13.1 and $21.29{\times}10^{-11}(cm^2/sec)$ ($mlO_2/mL{\times}mmHg$). The measurement showed that the increased amount of oxygen permeability of the copolymer measured using the polarographic method range between 11.0% and 80.5%. Based on the results of this study, the produced copolymer is suitable for use as a material to high oxygen permeability hydrogel lenses.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.755-760
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• 2010

This study used 3-vinylanisole and 4-vinylanisole with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), NVP (N-vinyl-2-pyrrolidone) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Measurement of the physical characteristics of the copolymerized material showed that the refractive index is 1.4496 - 1.4894, water content 22.93 - 35.50%, visible transmittance 88.8 - 90.8%. Also, measurements showed that the refractive index increased while the water content decreased as the ratio of 3-vinylanisole and 4-vinylanisole increased. And in cases of copolymer with 3-vinylanisole, 4-vinylanisole (added 15%) the results showed transmittance of 52.8 - 82.2%, 13.2 - 26.2% respectively for UV-A and UV-B showing that they have UV-blocking effects. Based on the results of this study, the produced copolymer can be estimated to be suitable for use as ophthalmic lens material for high refractive index and UV- blocking effects.

• Journal of Pharmaceutical Investigation
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• v.17 no.3
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• pp.111-126
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• 1987

Methyl methacrylate-butyl methacrylate copolymer (MMBM)-dibutyl phthalate (DBP) films were investigated as a potential topical drug delivery system for the controlled release of nitrofurazone. The kinetic analysis of release data indicated that drug release followed a diffusion-controlled granular matrix model, where the quantity released per unit area is proportional to the square root of time. DBP of several hydrophobic plasticizers selected was found to give the highest release of nitrofurazone. However, hydrophilic plasticizers such as propylene glycol and polyethylene glycol 400 had no controlled release properties and acceptable film formation. The effects of changes in film composition, drug concentration, film thickness, pH of release medium, and temperature on the in vitro release of nitrofurazone were analyzed both theoretically and experimentally. The release rate constant (k') was found to be proportional to DBP content, pH, and the temperature of release medium, but independent of film thickness, and drug concentration in a range of 0.1-0.4% by weight. The linear relationship was found to exist between the log k' and DBP content. The release of nitrofurazone from MMBM-DBP (8:2) films was found to be an energy-linked process. Two energy terms were calculated ; the activation energy for matrix diffusion was 13.45 kcal/mole, and the heat of drug crystal solvation was 27.26-29.34 kcal/mole. Observation of scanning electron micrographs and microscopic photographs showed that the incorporation of DBP in films increased markedly the particle size of nitrofurazone dispersed in the film matrix, comparing with the fine dispersion of nitrofurazone in pure MMBM film alone.

• Membrane Journal
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• v.20 no.3
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• pp.203-209
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• 2010

Amphiphilic graft copolymers based on poly(epichlorohydrine) (PECH) were synthesized using atom transfer radical polymerization (ATRP). Successful graft polymerization of poly(methyl methacrylate)(PMMA) and poly(butyl methacrylate) (PBMA) from PECH was confirmed by nuclear magnetic resonance ($^1H$ NMR) and FT-IR spectroscopy. Upon the introduction of KI or LiI to the graft copolymers, the ether stretching bands were shifted to a lower wavenumber due to coordinative interactions. Ionic conductivities of PECH-g-PBMA complexes were always higher than those of PECH-g-PMMA complexes, resulting from higher mobility of rubbery PBMA chains. The maximum ionic conductivity of $2.7{\times}10^{-5}\;S/cm$ was obtained at 10 wt% of KI for PECH-g-PBMA electrolytes.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.452-463
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• 2019

Objectives: The purpose of this study is to evaluate airborne concentrations of volatile organic compounds(VOCs) during nail art practice by college students. Methods: Personal samples for students were measured using passive samplers(OVM 3500) during three kinds of practice, including polish nail, gel nail and acrylic French sculpture at two universities located in Gyeongsangbuk-do Province. We also monitored area concentrations using active samplers and real-time total VOC monitors(ppbRAE 3000). All samples were analyzed with a gas chromatography flame ionized detector. Statistical analysis for monitored data were conducted using a web-based Bayesian toolkit, EXPOSTATS(www.expostats.ca). Results: Twenty-four personal samples and ten area samples were collected and five chemicals(acetone, butyl acetate, ethyl acetate, ethyl methacrylate(EMA) and methyl methacrylate(MMA)) were detected. Acetone was detected in all personal samples and ranged from 2.58 ppm to 50.3 ppm. EMA was detected in all personal and area samples with a maximum concentration of 9.78 ppm during acrylic French sculpture. Personal exposure levels to acetone, butyl acetate and mixtures were significantly higher with high occupant density (p<0.05). Geometric mean (GM) concentrations of 3.61 ppm for EMA personal samples were significantly higher than that of area samples, 1.5 ppm (p<0.05). Since there was no local ventilation, total VOC concentration continued to increase as the practice progressed. Conclusions: In order to minimize VOCs exposure for trainees, it is necessary to introduce a local ventilation system and maintain adequate occupant density.

• Journal of the Korean Chemical Society
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• v.62 no.6
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• pp.433-440
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• 2018

The pyrolysis has been universally applied to recycle the waste artificial marble. However, the existing heat treatment equipment has relatively low heat transfer efficiency into the inner part of the waste artificial marble. Besides, it leads to unnecessary excessive gas during the partial carbonization of the polymethyl methacrylate (PMMA) and raises the risk of fire due to heat at an extremely high temperature. This study suggests the process of pyrolysis at the formation state after adding the starch to waste artificial marble to overcome above-mentioned problems. As the result of experiments, this method showed that the pyrolysis of waste artificial marble was greatly improved at comparatively low temperature condition of $350^{\circ}C$. Moreover, it also manifested the effect on securing the stability and energy savings necessary for the recovery of methyl methacrylate (MMA) and ${\alpha}$-alumina (${\alpha}-Al_2O_3$).

• Korean Journal of Materials Research
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• v.10 no.12
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• pp.825-830
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• 2000

The copolymers with various composition of vinylbenzyl chloride (VBC), methyl methacrylate (MMA), and 2-hydroxyethyl methacrylate(HEMA) were synthesized as a humidity sensitive material and quaternized with N, N, N', N'-tetraethylene diamine.. Resistance versus relative humidity decreased with increase in the content of MMA in the copolymer. The introduction of HPMA increased the resistance of the humidity sensor as well as enhanced the adherence to the alumina substrate. In the case of VBC/MMA/HEMA=80/10/10, the hysteresis and temperature dependency coefficient were $\pm$2%RH and -0.46~0.42%RH/$^{\circ}C$. The average resistance at 30%RH, 60%RH and 90%RH were 3.0M$\Omega$ ,200k$\Omega$ and 9k$\Omega$, respectively.

• Polymer(Korea)
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• v.38 no.5
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• pp.671-675
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• 2014

Well-defined star shaped and linear block copolymers were synthesized to study the dispersion stability of copper phthalocyanine (CuPc). We synthesized dispersants using (2-dimethylamino) ethyl methacrylate (DMAEMA) and poly(ethylene glycol) methyl ether methacrylate) (PEGMA) by activators generated by electron transfer (AGET) atom transfer radical polymerization (ATRP). pDMAEMA-b-pPEGMA copolymers were characterized by GPC and NMR. Furthermore, we studied the effect of the dispersion stability of copper phthalocyanine by controlling the degree of polymerization of PEGMA as a stabilizing group. The 4-arm star shaped polymeric dispersant showed better dispersion stability of CuPc at $25^{\circ}C$ for 7 days.