• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.10-15
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• 2020

Ultraviolet rays, which have wavelengths smaller than 400 nm, are very harmful to the eyes. Recently, high-energy visible light was also revealed to be harmful to retinal cells. Therefore, polymer eyeglass lenses that can block UV and high-energy visible light are needed for eye health. In this study, high-refractive-index polymer eyeglass lens, n=1.67, were manufactured using the injection-mold method with the m-xylene diisocyanate monomer, 2,3-bis((2-mercaptoethyl)thio)-1-propanethiol monomer, benzotriazole UV absorber, release of alkyl phosphoric ester, dye mixture of CI solvent violet 13, and catalyst of dibutyltin dichloride mixture. A multi-layer anti-reflection coating was applied to manufactured polymer eyeglass lenses for both sides using an E-beam evaporation system. The optical properties of the manufactured lenses with the UV and high-energy visible light-blocking function were analyzed by UV-visible spectrophotometry. As a result, the polymer eyeglass lens with a UV absorber of 0.5 wt. % blocked 99% of UV and high-energy visible light shorter than 411 nm. The average transmittance of the polymer eyeglass lens with a UV absorber of 0.5wt.% was 97.9% in the range of 460 ~ 660 nm for photopic eye sensitivity higher than 10%. Therefore, clear image acquisition in photopic vision is possible.

• Journal of the Korean Professional Engineers Association
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• v.27 no.5
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• pp.39-45
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• 1994

스치로폴은 발포폴리스티렌(EPS : Expanded Poly-Styrene)을 말하며, 이것은 스티렌모노머(Stone Monomer)를 중합하여 만든 플리스티렌과 여기에 첨가한 발포제가 주원료로 되어 있다. 폴리스티렌은 1930년대에 미국과 독일에서 공업화되었고 스치로폴은 1943년 초에 미국에서 공업화가 이루어져 건물의 단열재, 물품포장재 등으로 이용되어 왔다. 1972년에는 노르웨이에서 연약지반상 교량의 접속도로 보수공사에 처음 스치로폴 성토공법이 이용되어 교대의 측방유동 방지대책으로 성공을 거둠에 따라 연약지반상의 경량성 토재 및 토압을 받는 옹벽, 교대 등 구조물의 경량 뒷채움재로서 각광을 받게 되었다. 한편 우리나라에서는 1994. 6월에 한국지반 공학회 주최로 개최된 "발포폴리스티렌(EPS) 이용 성토공법 국제심포지엄"에서 양산-구포간 고속도로성토(L=70m) 및 서해안고속도로의 교대 뒷채움에 스치로폴 경량성토재가 이용된 문헌이 발표된 바 있으며, 시중에서 단열재용으로 판매되고 있는 스티로폴 평판의 규격은 표 1과 같다. 스치로폴은 그 가격이 비싼 편이지만 단위중량(20-40kgf/m$^3$)이 흑의 50/1-100/1 밖에 안되는 초경량재로서 강도, 내구성 및 시공성이 우수한 성토용 신재료이기 때문에 연약지반상에서 구조물 시공시 지반의 과대한 침하, 측방유동 및 사면활동 등이 생길 경우 도로성 토재 또는 교대, 옹벽 등 구조물의 뒷채움재로서 스치로폴을 사용하면 이를 방지할 수 있으므로 매우 효과적인 토목자재라 할 수 있다. 따라서 본고에서는 지금까지의 연구결과, 시험시공 및 시공실적 등을 토대로 발표된 참고문헌을 중심으로 연약지반상 스치로폴 성토공법의 설계방법에 대하여 간단히 소개하고자 한다. 소개하고자 한다.

• Polymer(Korea)
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• v.39 no.1
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• pp.13-22
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• 2015

A new methacrylate copolymer that includes chalcone as a side group, poly(4-methacryloyloxyphenyl-4'-methoxystyryl ketone-co-styrene) was synthesized by free radical copolymerization. FTIR and $^1H$ NMR spectroscopic techniques were used to characterize the homopolymers and copolymers. The copolymerizations were carried out to high conversions. Copolymer compositions were established by $^1H$ NMR spectra analysis. The monomer reactivity ratios for copolymer system were determined by the linearized Kelen $T{\ddot{u}}d{\ddot{o}}s$, and Extended Kelen $T{\ddot{u}}d{\ddot{o}}s$ methods and a non-linear least squares method. The molecular weights and polydispersity index of copolymers were measured by using the gel permeation chromatography (GPC). The effect of copolymer compositions on their thermal behavior were studied by differential scanning calorimetry and thermogravimetric analysis methods. The optical properties of the resulting copolymer were also investigated.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.30-35
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• 2020

In this study, polyurethane-silica composite foams were synthesized to analyze thermal insulation characteristics and mechanical properties. In order to synthesize polyurethane-silica composite foams, polyester-silica composite polyols were first synthesized via a polymerization reaction with silica sol, dicarboxylic acid and glycol in monomer state. Physical properties of polyurethane-silica composite foams synthesized using the composite polyols were analyzed. From the thermal conductivity analysis, no significant differences among HPUF0, HPUF1, HPUF3 and HPUF5 were found. The compressive strength of polyurethane-silica composite foams increased as the silica content increased. The mechanical property of HPUF5 was also about 25% higher than that of HPUF0.

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.350-355
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• 1996

Poly(AA-co-EGDMA) microgels were prepared by precipitation polymerization in highly swollen polystyrene gel solution. The polymerization was carried out in selective solvent such as cyclohexane/acetone at $60^{\circ}C$. Poly(AA-co-EGDMA) microgels with various site of $0.18{\sim}0.55{\mu}m$ were obtained from different concentration of polystyrene(PS), concentration of crosslinking agent(EGDMA), ratio of Ps/monomer and volume ratio of solvents. The particle size of poly(AA-co-EGDMA) microgels decreased with increasing the concentration of PS and increased with that of EGDMA.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.804-810
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• 1997

A new catalyst system composed of a main catalyst(copper chloride) and promotors of zinc chloride, tin, and cadminum showed excellent performances in the MCS synthesis from silicon and methylchloride. The mixture of catalyst/silicon(5/95), Zn/Cu=0.1, Sn/Cu=0.001, and Cd/Cu=0.001 was mixed in a slurry phase and activated into the contact mass, then it was used for MCS synthesis. The average selectivity was 92% at the silicon consumption of 92% and reaction rate was 175(g-MCS/hr.kg-silicon) at conversion of silicon.

• Elastomers and Composites
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• v.43 no.4
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• pp.221-229
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• 2008

Starch as matrix polymer was used to do graft copolymerization with 2-ethylhexylacrylate, methyl methacrylate and acrylic acid. The polymerization was carried out by radical emulsion polymerization with increasing contents of starch. When 0.174% of $\alpha$-amylase as enzyme for starch was added, it was found that it made the best stable emulsion. The glass transion temperature of the polymerized material was increased with starch contents. The particle size and viscosity of the emulsion increased with starch contents due to the increased hydroxy group. Peel strength also increased with contents of starch because the enhanced hydroxy group caused to increase affinity between substrate surface and polymer materials. However, the initial tackiness decreased with starch contents owing to film hardness by higher glass transion temperature.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.71-84
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• 1992

Polymer-Impregnated Concrete(PIC) is a composite material of concrete and polymer. PIC has superior properties compared to conventional cement concrete, such as strength, stiffness, toughness, durability, water-proofing, chemical resistance. However, the usage of PIC has been limited to repairing materials and non-structural applications due to the lack of the design criteria and the analytical model to determine structural behavior. The objective of this study is experimentally to develop the optimum mixing proportions of polymer impregnants and the stress-strain responses, the strength characteristics, the fatigue and creep behaviors, and the durabilities of MMA(methyl methacrylate)-based PIC.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.4
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• pp.100-106
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• 2007

In this paper, first we went through the deliming and degreasing as pre-treatment of limed pelt scrap which is derived from liming process during leather manufacturing processing. After that, we produced fine collagen using non-chrome tanning and heat treatment and using acryl monomer graft polymerization such as GMA and MMA. From the comparisonof final products made by various methods, they showed good features in pyrolysis temperature, heat-resisting, variation of moisture content and particle distribution.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.157-165
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• 1997

The transesterification reaction could be used to the technical production as it forms an in-situ compatibilizer during the processing of polymer blends. Thus, TR-4,6(poly(tetramethylene-4,4'-terephthaloyldioxydibenzoate-co-hexametylene-4,4'-terephthaloyldioxydibenzoate), one of thermotropic liquid crystalline polymers was synthesized and was blended with PBT(polybutylene terephthalate), one of engineering plastics, to study the transesterification reaction. The transesterification reactions between two components, TR-4,6 and PBT, were monitored by IR, DSC and $^{13}C-NMR$ and analyzed by a statistical treatment method. Also, the reaction rates and the sequence distributions of repeating unit were (calculated and) invesitigated.