• Journal of the Optical Society of Korea
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• 제11권4호
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• pp.183-191
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• 2007

The highest diffraction efficiency(DE) value after illumination and post-curing of photopolymer films were obtained at the $SeO_2$/Acrylamide(AA) Ratios of AA 3.0 g, $SeO_2$ 1.0g and the DE's were stable values of over 90%. By the addition of $SeO_2$, the maximum DE at the initial stage of illumination was reached at 300 seconds, which suggests $SeO_2$ slows down the photopolymerization of AA, which enhances the maximum DE value by giving more migration time. DE variation curve for the optimum composition during extended-time illumination of 9,000 seconds resembles a sine curve due to the combination of the monomer diffusion and the photopolymerization, and the photopolymer film expanded by about 8% after photopolymerization due to monomer migration.

• 대한화학회지
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• 제13권4호
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• pp.373-377
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• 1969

In order to determine the monomer reactivity ratio in copolymerization of acrolein, the copolymerization of acrolein with styrene, methyl methacrylate and vinyl acetate respectively was studied. The Q and e value of acrolein in each copolymerization were also calculated from those of monomer reactivity ratios, but the calculated values were slightly different from each other. The Q and e of acrolein for the system of acrolein-styrene copolymerization were Q = O.64 and e = O.62 respectively. Relations among the Q and e value, the composition and structure of copolymers and the mean sequence length in copolymerization were also discussed for acrolein copolymers.

• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.479-482
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• 1992

Several poly(alkyl methacrylate-b-t-butyl methacrylate) diblock copolymers were synthesized by group transfer polymerization. The molecular weight of poly(t-butyl methacrylate) segments and the composition of the resulting block copolymers were controlled by the monomer feed ratios and mole ratios of monomer to initiator. The poly(t-butyl methacrylate) block was quantitatively hydrolyzed to poly(methacrylic acid) block by refluxing with a catalytic amount of p-toluenesulfonic acid in dioxane at $100^{\circ}C$ for 12 hrs. The thermogravimetric analysis of poly(alkyl methacrylate-b-t-butyl methacrylate) exhibited the lose of isobutylene and subsequent anhydride formation in the range of $205-300^{\circ}C$.

• 전기화학회지
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• 제7권4호
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• pp.189-193
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• 2004

본 연구에서는 POAGA와 TEGDMA로 구성된 반응성 단량체에서 두 단량체 및 개시제의 조성에 따른 겔폴리머전해질전지를 제조하고 전지특성을 평가하였다 POAGA계 겔폴리머전해질은 단량체의 함량이 증가함에 따라 겔화 시간은 감소하였다. POAGA계 겔폴리머전해질은 4.5V까지 전기화학적으로 안정하였으며, 상온 이온전도도는 약 $5.2\times10^{-3}Scm^{-1}$이었다. POAGA계 겔폴리머전해질을 채용한 리튬이온폴리머전지는 반응성 단량체의 함량이 $5.0wt\%$ 및 $7.0wt\%$인 경우에 비하여 $3.0wt\%$인 경우가 고율, 저온 및 사이클 특성이 우수하였다 또한 개시제 함량은 $1.0\~3.0wt\%$ 범위에서는 $1.0wt\%$인 경우가 우수한 전지특성을 나타내었다.

• Macromolecular Research
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• 제16권3호
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• pp.231-237
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• 2008

Biodegradable poly($\varepsilon$-caprolactone-co-L-lactide)-b-poly(ethylene glycol) (PCLA-b-PEG) copolymers were synthesized via solution polymerization by varying the feed composition of $\varepsilon$-caprolactone ($\varepsilon$-CL) and L-lactide (LLA) ($\varepsilon$-CL: LLA= 10:0, 7:3, 5:5, 3:7, 0: 10). The feed ratio based on weight is in accordance with the copolymer composition except for the case of $\varepsilon$-CL: LLA=3:7 (C3L7), which was verified by $^1H$-NMR. Two different approaches were used for the exceptional case, which is an extension of the reaction time or the sequential introduction of the monomer. A copolymer composition of $\varepsilon$-CL: LLA=3:7 could be obtained in either case. The chemical microstructure of PCLA-b-PEG was determined using the $^{13}C$-NMR spectra and the effect of the sequential structure on the thermal properties and crystallinity were examined. Despite the same composition ratio of the copolymer, the microstructure can differ according to the reaction conditions.

• 공업화학
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• 제10권6호
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• pp.954-959
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• 1999

본 연구에서는 소수특성의 PP 정밀여과막에 방사선을 조사하여 친수성 모노머인 2-hydroxyethyl methacrylate(HEMA), acrylic acid(AAc) 및 methacrylic acid(MAAc)를 그라프트 중합하였다. 3가지 모노머에 대한 그라프트 중합반응에서 물/메탄올 혼합용매의 조성에 따라 그라프트율에 미치는 효과를 조사하였으며, 이에 대한 각 모노머의 농도에 따른 영향을 고찰하였다. 가장 높은 그라프트율을 얻는 용매조건은 AAc는 순수한 물에서, MAAc는 물/메탄올 혼합비가 50/50 vol %에서, 그리고 HEMA는 25/75 vol %이었다. 그라프트된 PP 다공성 분리막의 모노머 도입여부와 표면특성변화는 FTIR-ATR 및 SEM을 이용하여 관찰하였다. 또한 인장강도와 연신율을 측정하여 그라프트율에 따른 막의 기계적 특성을 평가하였다. 그라프트된 PP막은 본래의 PP막보다 물 투과속도가 증가하였으며, 물 투과에 적당한 모노머로 HEMA임을 알았고 99%의 그라프트율에서 가장 좋은 물 투과속도를 보였다. 또한 AAc가 그라프트된 PP막 및 MAAc가 그라프트된 PP막의 물 투과속도는 pH나 $Cu^{2+}$에 의해 크게 좌우되나 HEMA는 pH나 $Cu^{2+}$에 영향이 거의 없었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.788-791
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• 1996

A mathematical model is developed for thermal solution copolymerization of styrene and acrylonitrile in a continuous stirred tank reactor(CSTR). Computational studies are carried out with the continuous copolymerization system model developed in this work to give the monomer conversion, copolymer composition and the average molecular weights of the copolymer. By performing the dynamic analysis of the reaction system, the polymer properties against the changes in the operating conditions are determined quantitatively. The cascade PID and fuzzy controller show satisfactory performances for both set point tracking and disturbance rejection. Especially, the fuzzy controller is superior to the PID controller.

• Bulletin of the Korean Chemical Society
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• 제1권4호
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• pp.138-143
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• 1980

Hydrogel membranes were prepared by copolymerizing 2-hydroxyethyl methacrylate (HEMA) and N-vinyl-2-pyrrolidone (VP) in the presence of the solvent and the crosslinker tetraethyleneglycol dimethacrylate (TEGDMA). By changing the monomer composition and the crosslinker content, different membranes were synthesized. Using these membranes, relative permeabilities and distribution coefficients for amides including urea were measured. The water contents in membrane were also measured. On the basis of solute-membrane matrix interaction, the results were interpreted.

• 접착 및 계면
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• 제3권1호
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• pp.9-12
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• 2002

In this paper, N,N-m-phenyenedimaleimide (m-PDM), Polyamide Resin (PI) and Metallic dimethacrylate etc. influencing the heat resistance of anaerobic adhesive has been studied, an anaerobic adhesive composition capable of post-cure expansion and $230^{\circ}C$ temperature resistance comprising a multifunctional methacrylate and m-PDM capable of effectuating expansion upon post-cure has been developed. A homogeneous mixture of a monomer and m-PDM are subjected to a first cure heat stage (Room Temperature) wherein a rigid partially-cured plastic is formed and a post-cure heat stage ($150^{\circ}C$) to effectuate permanent expansion of cured adhesive composition.

• 센서학회지
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• 제24권2호
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• pp.88-92
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• 2015

In order to study the semi-conductive characteristics of carbon black-filled ethylene-propylene-diene monomer (EPDM) composite film, which is used for measuring occlusal force, composite samples with volume ratios of carbon black to EPDM ranging from 30% to 70% were prepared. The process of making a composite film consists of two steps, which involve the preparation of a slurry composition and the fabrication of a thin film using solution casting and a lamination process. To prepare the slurry composition, we dispersed carbon black nanoparticles into an organic solvent before mixing with an EPDM solution in toluene. The mechanical and electrical properties of the resulting carbon black-filled EPDM film were then investigated, and the results showed that the electrical resistance of a film decreases with the increase in the carbon black content. Furthermore, improved elastic recovery was observed after cross-linking the EPDM.