• Composites Research
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• 제26권3호
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• pp.182-188
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• 2013

본 연구의 목적은 silorane 기질의 치아 수복용 복합레진의 중합수축과 수축응력의 동력학을 평가하고 전통적인 methacrylate 기질의 복합레진과 비교하기 위함이다. 두 종의 methacrylate 기질의 복합레진(Z250, Z350 flowable)과 silorane 기질 복합레진(P90)이 사용되었다. 아르키메데스 원리를 응용해 자체 제작한 중합수축 측정 장치를 사용하여 광중합 중 일어나는 복합레진의 체적 중합수축을 측정하였고 스트레인게이지로 중합수축응력을 측정하였다. Silorane 기질 복합레진인 P90의 중합수축과 최대 중합수축률이 가장 낮았고 methacrylate 기질 복합레진인 Z350 flowable이 가장 높았다. Methacrylate 기질의 복합레진과 비교하여 silorane 기질의 복합레진 P90이 최대 수축률에 이른 시간은 더 길었고 중합수축응력은 낮았다.

• 접착 및 계면
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• 제7권1호
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• pp.23-29
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• 2006

Polymer thin films of pentafluorostyrene (PFS) were prepared by RF plasma (13.56 MHz) polymerization in continuous wave (CW) mode, as a function of plasma power and monomer pressure. Conditions for film preparation were optimized by measuring the solvent resistance of plasma polymer thin films in DMAc, NMP, THF, acetone and chloroform, as well as by evaluating the optical clarity via UV-VIS measurements. Pulsed mode plasma polymerization was also utilized to enhance the optical properties of the films by varying the period of on-time and duty cycle. Finally, the films were subjected to refractive index measurements and analyzed by ${\alpha}$-step, TGA and FT-IR.

• Journal of Microbiology and Biotechnology
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• 제5권3호
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• pp.177-180
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• 1995

In horseradish peroxidase-catalyzing polymerization of phenol under the water/dioxane solvent system, the optimal concentration of hydrogen peroxide was found to be 10 mmol/I. Feeding of hydrogen peroxide at its optimal concentration improved the polymerization performance by reducing reaction time and increasing molecular weights. Monomer conversions and the molecular weights of the enzymatically produced polymer were in the ranges of 83.1~94.2$%$ and 58000~68000, respectively.

• Macromolecular Research
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• 제12권2호
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• pp.240-245
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• 2004

Monodisperse PMMA micro spheres are prepared by means of a simple soap-free emulsion polymerization in methanol-enriched aqueous medium in a single step process. The size and uniformity of the microspheres are dependent on the polymerization temperature. In a stable system, the uniformity is improved with the polymerization time. The most uniform and stable micro spheres are obtained under mild agitation speed of 100 rpm at 70$^{\circ}C$. The monodisperse PMMA microspheres in the size range of 1.4-2.0 $\mu\textrm{m}$ having less than 5% size variation are successfully achieved with varying concentrations of monomer and initiator. As the monomer and initiator concentrations increase, the larger micro spheres with enhanced uniformity are obtained. However, the decreased amount of water induces the polydisperse PMMA particles due to the generation of secondary particles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.183-186
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• 1991

In order to prepare the functional organic optic meterials, the capacitive coupled gas flow type plasma polymerization apparatus was designed and manufactured. Styrene and para-Xylene monomer were adopt as organic materisl. Optical constant, refrative index, extinction coefficient of organic thin films by the gas flow type plasma polymerization appratus were determined by envelope method using spectrophotometry. The refractive index of plasma polymerized thin films was decreased in accordance to increase of wave length and discharge time. The extinction coefficient was very small compared with refractive index. From the experimental result of optical constant and film thickness, it was considered that the films which had required optical properties and thickness can be prepared by control of polymerization condition.

• 한국염색가공학회지
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• 제1권1호
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• pp.63-68
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• 1989

It has been attempted to improve the anti-static property of Nylon 6 by means of Vapor-phase polymerization of thiophene in Nylon 6/PVA blend films impregnated with aluminium chloride as an oxident. After Polymerization of thiophene for two hours in Nylon 6/PVA blend films the conductivity increased from $10^{-12}-10^{-13}S/cm\;to\;10^{-5}-10^{-7}$S/cm, and the conductivity of composite films increased with increasing the concentration of aluminium chloride, the content of PVA annd polymerization time of thiophene. Polythiophene introduced in Nylon 6/PVA blend films has been confirmed by FT-IR spectra and scanning electron micrographs.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.199-199
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• 2006

Microwave-irradiation has become a common heat source in organic chemistry in the last decade. In recent years, polymer chemists also discovered the advances of microwave heating that include fast and efficient heating as well as the homogeneous heat profile and the easy access to pressurized reaction conditions. In this contribution, we report our investigations on the cationic ring-opening polymerization of 2-oxazolines that lead to a tremendous acceleration from several days to several minutes polymerization time. In addition, the optimized microwave-assisted polymerization procedure was applied for the preparation of libraries of diblock and triblock copolymers that were used for the determination of structure-property relationships in poly(2-oxazoline)s.

• 대한치과의사협회지
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• 제11권1호
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• pp.37-40
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• 1973

The auther measured exothermic tempreature of the 5 kinds of direct resins during polymerization. Direct resins were mixed into the rubber cup(550-600㎣ in volume) with grass rod at room temperature (23.6℃) for 30 seconds and thermometer was placed approximately at the geometric center of the resin mass in the rubber cup. Polymer-monomer ratio was determined by instruction of the packages. The results were as follows. 1) The heat generated during polymerization was under 47.3℃. 2) The time at which the highest temperature is reached during polymerization was within 20.5 minutes. 3) Slow curing resins produced lower heat than quick curing resins and quick curing resins presented higher temperature than slow curing resins. 4) The highest temperature was sustained momentarily.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.306-316
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• 2009

In this study, block copolymer of polystyrene and polyethylene glycol methyl ether methacrylate(PEGMA) by ATRP(atom transfer radical polymerization) method was synthesized. 4 arm-molecule which contained halogen atom was synthesized for an initiator. With 4 arm-molecule monodispered polystyrene were synthesized by ATRP method. The molecular change of synthesized monodispersed polystyrene with respect to time was investigated and living polymer characteristic was confirmed. Block copolymer of polystyrene and polyethylene glycol methyl ether methacrylate(PEGMA) was synthesized by ATRP with macroinitiator which was synthesized from the monodispersed polystyrene(Mn=12000). The molecular weight of obtained PS-b-PEGMA was 22,000.

• 한국전기전자재료학회논문지
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• 제18권1호
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• pp.68-74
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• 2005

In this work, polymerization conditions of the gel polymer electrolyte (GPE) were studied to obtain better electrochemical performances in a lithium-ion polymer battery. When the polymerization temperature and time of the GPE were 70$^{\circ}C$ and 70 min, respectively, the lithium polymer battery showed excellent a rate capability and cycleability. The TMPETA (trimethylolpropane ethoxylate triacrylate)/TEGDMA (triethylene glycol dimethacrylate)-based cells prepared under optimized polymerization conditions showed excellent rate capability and low-temperature performances: The discharge capacity of cells at 2 Crate showed 92.1 % against 0.2C rate. The cell at -20 $^{\circ}C$ also delivered 82.4 % of the discharge capacity at room temperature.