• 한국재료학회지
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• 제29권12호
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• pp.735-740
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• 2019

The purpose of this study is to fabricate an ophthalmic lens by copolymerizing two types of carbon nanotubes and hydrophilic hydrogel lens materials, and to investigate its application as an ophthalmic lens material by analyzing its physical properties and antimicrobial effect. For polymerization, HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate), a crosslinking agent, and AIBN (azobisisobutyronitrile), an initiator, are used as a basic combination, and a single-walled carbon nanotube and a single-walled, carboxylic-acid-functionalized carbon nanotube are used as additives. To analyze the physical properties, the water content, refractive index, breaking strength, and antimicrobial effect of the fabricated lenses are measured. The fabricated lenses satisfies all the basic properties of the basic hydrogel ophthalmic lens. The water content increases with increasing amount of additive and decreases with addition of 0.2 % ratio of nanoparticles. The refractive index is inversely proportional to the water content result. As a result of the antimicrobial test of the fabricated lens, the addition of carbon nanotubes shows an excellent antimicrobial effect. Therefore, it is considered that the fabricated lens can be applied as a functional material for basic ophthalmic hydrogel lenses.

• 통합자연과학논문집
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• 제9권4호
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• pp.249-254
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• 2016

This study evaluated the physical and optical characteristics of hydrophilic ophthalmic polymer with addition of 2-methacryloyloxyethyl phosphorylcholine in the basic hydrogel ophthalmic lens material, and in particular, the utility of 2-methacryloyloxyethyl phosphorylcholine as an ophthalmic contact lens material for ophthalmologic devices was investigated. In this study 2-methacryloyloxyethyl phosphorylcholine were used as additives. For the preparation of hydrogel lens 2-hydroxyethyl methacrylate, methyl methacrylate, acrylic acid and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The physical properties of the produced polymers were measured as followings. The refractive index of 1.433~1.393, water content of 35.95~53.16%, contact angle of $70.6{\sim}51.24^{\circ}$, UVB transmittance of 81.2~82.4%, UV-B transmittance of 81.2~82.4% and visible transmittance of 91.4~92.2% were obtained. Also, in case of protein absorption, the measurement showed that absorbance of Reference and MPC-10 sample was 0.2598 and 0.2250 respectively. Based on the results of this study, ophthalmic lens material containing 2-methacryloyloxyethyl phosphorylcholine is expected to be used usefully as a material for high wettability and inhibitor of protein adsorption for ophthalmic hydrogel lens.

• 통합자연과학논문집
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• 제11권2호
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• pp.113-120
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• 2018

This study was planned to prepare the high strength hydrogel ophthalmic lens containing isocyanate group and nanoparticles. HDI with carbon nanoparticles were used as additives for the basic combination of HEMA, MA and MMA, and the materials were copolymerized with EGDMA as the cross-linking agent and AIBN as the initiator. The mixture was heated at $100^{\circ}C$ for an hour to produce the high performance hydrogel ophthalmic lens by cast mold method. Measurement of the physical characteristics of the produced material showed that the refractive index was in the range of 1.4027~1.4600, water content 25.21~44.01%, contact angle $54.18{\sim}72.94^{\circ}$, visible light transmittance 53.03~92.09%, and tensile strength 0.1024~0.2359 kgf and breaking strength was 0.0872~0.2825 kgf. The results showed an increase of refractive index while the decrease in water content. And also, the breaking strength was highest when the addition ratio of HDI was 5%(wt). As a result of the absorbance measurement, no significant difference was observed in all the samples, so it can be judged that the stabilization of nanoparticles in the polymer was maintained.

• Bulletin of the Korean Chemical Society
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• 제25권3호
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• pp.357-360
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• 2004

We developed in the present study molecular imprinted polymers (MIPs), using single templates (pentoxifylline, caffeine and theophylline) and mixed-templates (pentoxifylline-caffeine, pentoxifylline-theophylline and caffeine-theophylline). The MIPs were prepared with methacrylic acid (MAA) as the monomer, ethylene glycol dimetharylate (EGDMA) as the crosslinker and 2,2'-azobis(isobutyronitrile) (AIBN) as the initiator. The obtained polymer particles (particle size after grinding was about 25-35 ${\mu}$m) were packed into a HPLC column (3.9 mm i.d. ${\times}$ 150 mm). The selectivity and chromatographic characteristics of the MIPs were studied using acetonitrile as the mobile phase at a flow rate of 0.8 mL/min. UV detector wavelength was set at 270 nm. Different single template MIPs showed different molecular recognitions to the templates and the structurally analogues, according to the rigidity and steric hindrance of the compounds. Recognition was improved on the mixed-template MIPs as a result of the cooperation or sum effect of the templates, whereas on the pentoxifylline-theophylline imprinted polymer, the highest selectivity and affinity were obtained. Separations of the test compounds on different polymers were also investigated.

• 한국환경과학회지
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• 제19권1호
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• pp.97-103
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• 2010

The biodegradable oil absorption resin was prepared by the suspension polymerization of the modified starch and 2-ethylhexyl acrylate (2-EHA). The highest oil-absorption capacity of B-PEHA prepared showed at the condition of the modified starch content of 10 g and ethyleneglycol dimethacrylate (EGDMA) of 0.133 wt%. Its maximum oil absorption capacity per g of oil absorber was chloroform 30.88 g, toluene 19.75 g, xylene 18.78 g, tetrahydofuran (THF) 15.96 g, octane 11.43 g, hexane 9.5 g diesel oil 12.80 g, and kerosene 13.79 g, respectively. The biodegradation of poly-2-ethylhexylacrylate (B-PEHA) determined by enzymatic hydrolysis showed approximately 17~20%. The results showed that the preparation of the biodegradable oil absorption resin is available using the modified starch.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.276-280
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• 2007

In this work, caffeine and some catechin compounds + C, EC, EGC, and EGCG were extracted from green tea by using molecular imprinted polymers (MIP) as sorbent materials in a solid-phase extraction (SPE) process known as MISPE (molecular imprinted solid-phase extraction). For synthesis of MIP, caffeine was employed as the template, MAA as the monomer, EGDMA as the crosslinker, and AIBN as the initiator. A solution of caffeine (0.2 mg/mL in methanol) was utilized in the solid extraction cartridges following loading, washing, and elution procedures with acetonitrile, methanol, and methanol-acetic acid (90/10, %v/v) as the solvents, respectively. This solid-phase extraction protocol was applied for the extraction of caffeine and some catechin compounds from green tea. A comparison was made between the results obtained with the MIP cartridges and a traditional C18 reversed-phase cartridge. It was thereupon found that the recovery of caffeine by the MIPbased sorbent used in this work was almost two and four times greater than that by a commercially available C18 material. A quantitative analysis was conducted by high performance liquid chromatography (HPLC) using a C18 column (5 μm, 250 × 4.6 mm) with methanol/water (40/60, %v/v) as the mobile phase at a flow rate of 0.5 mL/min.

• 폴리머
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• 제32권3호
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• pp.219-229
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• 2008

A pH sensitive ternary copolymer gel was synthesized in the presence of ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent through radical polymerization of vinyl acetate (VA), acrylic acid (AA) and methyl acrylate(MA) with a weight ratio of 1 : 1.3 : 1. A number of experiments were carried out to determine the swelling behavior of the gel under a variety of pH conditions of the swelling medium. As the pH of the swelling medium was changed from 1.0 to 8.0 at $37^{\circ}C$, the gel showed a shift in the pH-dependent swelling behavior from Fickian (n=0.3447) to non-Fickian (n=0.9125). The resulting swelling parameters were analyzed using graphical and statistical methods. The results showed that the swelling of the gel was controlled by the pH of the medium, i.e. $n=n_o{\exp}(S_{C}pH)$, where n is the diffusion exponent, $n_o(=28.9645{\times}10^{-2})$ is the pre-exponential factor and $S_C$(=0.1417) is pH sensitivity coefficient. The swelling behavior of the gel was also examined in aliphatic alcohols. The results showed that the rate of swelling increased with increasing number of carbon atoms in the alcoholic molecular chain.

• Journal of Pharmaceutical Investigation
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• 제32권1호
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• pp.1-6
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• 2002

The mucoadhesive characteristics of [P(AA-co-PEGMM)] films by estimating the glass transition temperature $(T_g)$, analyzing surface energy and studying FT-IR was previously reported. In this study, the possibility of buccal mucoadhesive dosage form of [P(AA-co-PEGMM)] films by mucoadhesive force measurements and dissolution tests were also investigated. Mucoadhesiveness of [P(AA-co-PEGMM)] films was compared with cr-PAA and cr-PEGMM films crosslinked with 3% ethyleneglycol dimethacrylate (EGDMA). The buccal mucoadhesive force of [P(AA-co-PEGMM)] films increased with increasing content of PEGMM. [P{AA-co-PEGMM (18 mole%)}] films showed a significantly greater mucoadhesiveness than cr-PAA and cr-PEGMM films. The mucoadhesive force measured in normal saline (pH 5.0) was higher than that measured in phosphate buffer (pH 6.8) because of the pH dependence of hydrogels with carboxyl ions within the PAA. Moreover, the mucoadhesive force of [P{AA-co-PEGMM (18 mole%)}] films was at maximum after 2 hr attachment of buccal mocosa and it was maintained over $1\;N/cm^2$ for up to 10 hr. In dissolution studies, the release of butorphanol tartrate from [P(AA-co-PEGMM)] films increased with increasing PEGMM content, and films prepared with 18 mole% PEGMM gave almost zero order release kinetics.

• 통합자연과학논문집
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• 제9권1호
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• pp.16-22
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• 2016

The optical and physical and characteristics of hydrogel ophthalmic lens polymerized with addition of 2,6-difluoropyridine, SiPc(silicon 2,9,16,23-tetra-tert-butyl-29H31H-phthalocyanine dihydroxide) and nanodiamond in the basic hydrogel material were evaluated. In particular, the utility of 2,6-difluoropyridine, SiPc and nanodiamond as a hydrogel ophthalmic lens material was investigated. 2,6-difluoropyridine, SiPc and nanodiamond were used as additives. And also, 2-hydroxyethyl methacrylate, acrylic acid, methyl methacrylate and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The refractive index of 1.4348~1.4361, water content of 33.30~34.02%, UV-B transmittance of 4.77~67.50%, UV-A transmittance of 1.45~89.19% and visible transmittance of 32.12~92.21% were obtained. The results of hydrogel lens containing 2,6-difluoropyridine (add 5%) showed antibiosis for staphylococcus aureus. The produced copolymer is suitable for hydrogel soft ophthalmic lenses with antibiotic and anti-UV effect.

• 분석과학
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• 제19권3호
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• pp.218-225
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• 2006

A molecularly imprinted polymer (MIP) was synthesized by radiation-induced polymerization (RIP), where the ferulic acid was used as a template molecule, 4-vinylpyridine as a monomer and ethylene glycoldimethacrylate (EGDMA) as a cross-linking monomer. The MIP was packed in a glass column using a slurry method for use in medium pressure liquid chromatography (MPLC). The MPLC column was tested for separation and purification of ferulic acid from the rice oil. When repeated three times, the MPLC separation/purification yielded the ferulic acid with the purity higher than ~99%. The chemiluminescence of the luminal (5-amino-2,3-dihydro-1,4-phtalazinedione) measured on a potato disc slide (5.0 mm thick) was enhanced in the presence of ferulic acid, while, without the ferulic acid, the chemiluminescence of luminol on the potato slice disc was not observed, which suggests the ferulic acid obtained from the rice oil can be useful for immunoassay.