• 한국재료학회지
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• 제9권12호
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• pp.1160-1169
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• 1999

본 연구에서 FPC에 사용되는 동박과 접착제의 이종 재료간에 계면접착력을 향상시키기 위해 silane primer를 도입하였다. 또한 동박표면 및 에폭시 접착제를 개질하여 개질조건이 접착강도에 미치는 영향도 조사하였다. 본 실험은 접착제층과의 상용성을 고려하여 silane primer로 triethoxyvinylsilane을 용액 및 무유화제 유화중합한 고분자형태와 3-aminopropyl-triethoxysilane (3-APTES), 3-glycidoxypropylmethoxysilane (3-GPTMS)을 사용하여 접착제층과의 접착력 증진을 도모하였다. 동박표면은 1,1,1-trichloroethane을 사용하여 개질 시간에 따른 동박 표면의 지형변화와 그에 따른 접착강도를 조사하였다. 결과에 따르면 silane을 사용한 경우 동박-접착제간의 접착력이 약2 ~ 5배 정도 증진되었고, 동박표면의 개질시간은 약 10분 정도가 최적의 접착조건임을 알 수 있었다. 또한 저분자량 실란의 농도에 따른 접착력은 3-APTES는 약 0.5 vol.%에서 최고 접착력을 보였고, 3-GPTMS의 경우 약 0.2 vol.%에서 최고의 접착력을 보였다.

• Elastomers and Composites
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• 제52권4호
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• pp.272-279
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• 2017

The heterocoagulation of latex is a simple and useful method to fabricate various polymer nanocomposites in which a precise control of the colloid stability is essential. In this work, a multi-layered graphenes (MLGs)/poly(styrene-co-butyl acrylate) (P(S-co-BA)) nanocomposite having an excellent dispersion of MLGs was prepared via the sudden heating heterocoagulation process. The P(S-co-BA) component was obtained by emulsion polymerization. This process can effectively shorten the process and particles growth steps. The colloid stability of these dispersions was controlled by factors such as ionic charge, temperature, and reaction times. The influence of these factors on heterocoagulation was evaluated and the properties of the nanocomposites were investigated. The conductivity of the MLGs/P(S-co-BA) nanocomposites increased from -11.53 to -5.70 S/cm for an increase in MLG content from 0.01 to 5 wt%. Moreover, percolation threshold was observed in the case of 0.01 wt% MLGs.

• Macromolecular Research
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• 제11권6호
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• pp.425-430
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• 2003

Two types of poly(n-butyl acrylate) copolymer/silicate nanocomposites have been produced: poly(n-butyl acrylate-co-methyl methacrylate) [P(BA-co-MMA)]/silicate nanocomposites and poly(n-butyl acrylate-co-styrene) [P(BA-co-ST)]/silicate nanocomposites. The P(BA-co-MMA)/silicate nanocomposites shows the exfoliated structures but a P(BA-co-ST)/silicate nanocomposites have intercalated structures, because the BA/MMA comonomer has a higher polarity (e-value in Q-e scheme) than the BA/ST comonomer. The BA/MMA comonomer expanded the interlayer space of the silicate wider than did the BA/ST comonomer. The thermal degradation onset point of the P(BA-co-MMA)/silicate nanocomposites was 43$^{\circ}C$ higher than that of pure P(BA-co-MMA). P(BA-co-MMA)T5%, P(BA-co-MMA)T10%, and P(BA-co-MMA)T20% exhibit 134,302, and 195% increases, respectively, in their storage moduli at -20$^{\circ}C$ relative to the pure copolymer.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2661-2665
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• 2011

We studied the effect of structural and morphological changes on the conductivity of a stretched conducting polymer film. To improve the poor processability of polyaniline, we used dodecylbenzenesulfonic acid as both a surfactant and a dopant during emulsion polymerization, followed by blending with high-impact polystyrene. UV-Vis/NIR spectra were obtained to observe conformational changes, and SEM and AFM were used to investigate morphological changes. FT-IR dichroism was applied to determine the microscopic orientation, and XRD patterns were obtained for quantitative crystallinity analysis. The electrical conductivity (${\sigma}_{\parallel}/{\sigma}_{\perp}$) was measured as a function of draw ratio. We found a clear correlation between morphological changes and (${\sigma}_{\parallel}/{\sigma}_{\perp}$), especially at the stretching limit. The conductivity of the films can be modified according to the desired application by controlling their structure and morphology.

• Macromolecular Research
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• 제14권4호
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• pp.461-465
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• 2006

Two types of injectable system using thermosensitive chitosan (chitosan-g-NIPAAm), hydrogel and microparticles (MPs)-embedded hydrogel were developed as drug carriers for controlled release and their pharmaceutical potentials were investigated. 5-Fluorouracil (5-FU)-loaded, biodegradable PLGA MPs were prepared by a double emulsion method and then simply mixed with an aqueous solution of thermosensitive chitosan at room temperature. All 5-FU release rates from the hydrogel matrix were faster than bovine serum albumin (BSA), possibly due to the difference in the molecular weight of the drugs. The 5-FU release profile from MPs-embedded hydrogel was shown to reduce the burst effect and exhibit nearly zero-order release behavior from the beginning of each initial stage. Thus, these MPs-embedded hydrogels, as well as thermosensitive chitosan hydrogel, have promising potential as an injectable drug carrier for pharmaceutical applications.

• 공업화학
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• 제21권3호
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• pp.353-355
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• 2010

양이온성의 2,2'-azobis(2-methylpropionamidine) (AIBA) 개시제를 이용한 methylmethacrylate (MMA)의 무유화제 에멀전 중합을 통해 polymethylmethacrylate (PMMA) 입자를 합성하였다. 스퇴버 방법을 이용하여 양이온성의 PMMA 입자 표면에 실리카를 코팅하였다. 음전하의 실리카 전구체는 양이온성의 PMMA 입자 표면과의 정전기적 인력에 의해 코팅된다. 실리카 코팅 과정 중에 PMMA 입자가 용해되어 후처리 없이 실리카 중공체를 얻을 수 있었다.

• Archives of Pharmacal Research
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• 제13권4호
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• pp.293-297
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• 1990

Sustained release microspheres containing phenylpropanolamine HCI (PPA) were prepared with acrylic polymer (Eudragit RL/RS) sand hydroxypropylmethylcellulose phthalate (HPMCP) using a emulsion-solvent evaporation method. Magnesium strate was used a smoothing agent for preparation of microspheres. The microspheres obtained were very spherical and free-flowing particles. Scanning electron microscopy showed that microspheres have a smooth surface and a sponage-like internal structure. The dissolution rate of PPA from the microspheres was dependent on the pH of dissolution media. PPA showed faster relase in hP 1. 2 solution than in pH 7.4 solution due to the solubility of PPA. Therefore we prepared new microspheres containing 5% (w/v) HPMCP in order to control the release of PPA. The release rate of PPA from these new microspheres was similar in pH 1.2 and pH 7.4 solution.

• Macromolecular Research
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• 제17권6호
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• pp.397-402
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• 2009

In emulsifier-free, emulsion polymerization with ionizable comonomer, the ionization of the comonomer is critical in determining the size of the final polymerie particles at sub-micrometer scale. In this study, polystyrene latex beads with carboxylates on the surface were synthesized using acrylic acid as a comonomer. Specifically, ammonium hydroxide was added to the emulsifier-free polymerization system to promote the ionization of acrylic acid by increasing pH. Smaller polystyrene latex particles were produced by increasing the ammonium hydroxide concentration in the reaction system, due to the enhanced stability promoted by the ionization of acrylic acid during the nucleation step. In addition, the surface morphology of the polystyrene latex particles was controlled by the concentration of acrylic acid, the dissociation of which was influenced by the ammonium hydroxide concentration.

• 한국응용과학기술학회지
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• 제12권1호
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• pp.87-92
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• 1995

To prepare a O/W type durable softner(OESA), octadecamidoethylaminoethyl dodecate and tetra (2-dodecamidoethyl) urea synthesized as the main components of softner, were blended with polyoxyethylene(20) oleyl ether, sorbitan sesquioleate, and polyoxyethylene(7) stearyl ether in various compositions. Emulsion stability of OESA was good, and mixed HLB value was 9.7, OESA was found was to be good durable softner for nylon through the examination of softness, lubriation, antistatic property, bending resistance, and color fastness.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 춘계학술대회 논문집
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• pp.67-70
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• 1994

On this study, we fabricated humudity sensor with polyimide thin film from the nonaqueous emulsion by the electrophoretic deposition as a function of film thickness. then evaluated performance of the sensor with increasing relative humidity if constant temperature constant humidity chamber, which is electronically controlled. we designed upper electrode of the sensor to brush type to make moisture particles permeate into the polymer bulk. sensing properties of the sensor on % RH shows proportion on the low %RH. Fer the 30V-30S- 200$^{\circ}C$ sample, percentage changing of capacitance on from 30 %RH to 90 %RH is 45.8 %, and increasing rate per 1 % RH of capacitance is 11.25 pF