• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.903-904
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• 2010

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1081-1084
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• 2003

Structural morphology, annealing behavior and dielectric properties of polyaniline-emeraldine base (Pani-EB) and poly methyl methacrylate (PMMA) thin films prepared by spin coating technique have been studied. MIM and MISM structures were used to investigate annealing and dielectric behavior. The XRD and AFM spectrum of as grown and annealed thin films indicates the amorphous nature. The observed amorphous phase, low loss, dielectric behavior and thermal stability even at high temperatures implies the feasibility of utilizing PMMA and Pani-EB thin films as gate dielectric insulator layer in organic thin film transistors which can find application in flat panel display.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.11
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• pp.994-1000
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• 2003

In this study, gel polymer electrolytes (GPE) with semi-interpenerating network of poly (methyl methacrylate) and hexanediol dimethacrylate were synthesized and their electrochemical performances were evaluated. LiCoO$_2$/GPE/graphite cells were prepared and their performances depending on discharge currents and temperatures were evaluated. The precursor containing 5 vol% curable mixture had a low viscosity relatively. GPE showed good electrochemical stability up to potential of 4.8 V vs. Li/Li$\^$+/. Ionic conductivity of the gel polymer electrolyte at room temperature and -20$^{\circ}C$ was ca. 5.9 and 1.4${\times}$10$\^$-3/ Scm$\^$-1/, respectively. LiCoO$_2$/GPE/graphite cells showed good rate capability, low-temperature performance and cycleability.

• Macromolecular Research
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• v.16 no.4
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• pp.293-302
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• 2008

In our previous publication, the problem of particle deformation and coagulation at the nucleation stage in the presence of cross-linker was intensely studied by seeded batch dispersion polymerization of methyl methacrylate (MMA). In the present work, highly cross-linked, monodisperse PMMA particles were prepared under various reaction conditions by seeded semi-continuous process. Monodisperse, $6.5{\mu}m$-diameter PMMA particles containing up to 8 wt% of DVB or EGDMA were successfully made by seeded semi-continuous process and multi-semi-continuous addition process, respectively. Therefore, this study shows that seeded semi-continuous process is more effective and efficient to prepare highly cross-linked, monodisperse particles than non-seeded and seeded batch processes.

• Polymer(Korea)
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• v.25 no.5
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• pp.617-624
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• 2001

The core-shell composite latexes were synthesized by stage emulsion polymerization of methyl methacrylate (MMA) and styrene (St) with ammonium persulfate after preparing monomer pre-emulsion in the presence of anionic surfactant. However, in preparation of core-shell composite latex, several unexpected results are observed, such as, particle coagulation, low degree of polymerization, and formation of new particles during shell polymerization. To solve the disadvantages, We study the effect of initiator concentrations, surfactant concentrations, and reaction temperature on the core-shell structure of polymethyl methacrylate/polystyrene and polystyrene/polymethyl methacrylate. Particle size and particle size distribution were measured using particle size analyzer, and the morphology of the core-shell composite latex was determined using transmission electron microscope. Glass temperature was also measured using differential scanning calorimeter. To identify the core-shell structure, pH of the two composite latex solutions were measured.

• Polymer(Korea)
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• v.27 no.2
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• pp.152-158
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• 2003

Two commercial processing methods have been used to produce poly(methyl methacrylate) (PMMA) marbles; cell molding method and belt molding method. Cell molding method has low productivity and belt molding method has high equipment cost as well as high production cost. A new production method far PMMA marbles using plastic films as molds was studied in this investigation to overcome the shortcomings of cell molding and belt molding method. As plastic film molds for producing PMMA marbles, poly(vinyl acetate) film was used. A methyl methacrylate compound, which has good processability in film molding and shows good mechanical properties after curing, was prepared and used to produce PMMA marbles by film molding method. Properties of the PMMA marbles produced by film molding method were similar to, or higher than, those of commercial PMMA marbles produced by cell molding and belt molding method respectively. The film molding method is considered to have high possibility in commercial application.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.29-32
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• 2005

Poly (methyl methacrylate) (PMMA) is one of the promising representive of polymer gate dielectric for its high resistivity and sutible dielectric constant. PMMA (Mw=96700) films were prepared on p-Si by spin coating method. PMMA were coated compactively and flatly as observeed by AFM. MIS(Al/PMMA/p-Si) structure was made and capacitance-voltage (C-V) and current-voltage (I-V) measurements were done with PMMA films for different thermal treatment temperature. PMMA films were showed proper dielectric constant and breakdown voltage. Above the glass transition temperature PMMA films degraded. C-V measured at various frequencies, dielectric constant increased a little. The absence of hysteresis in the C-V characteristics, which eliminate the possibility of mobile charges in the PMMA films. The observed thermal stability, smooth surfaces, dielectric constant, I-V behavior implies PMMA formed by spin coating can be used as an efficient gate dielectric layer in OTFTs.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.6
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• pp.24-27
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• 1989

MTBE(Methyl Tertiary Butyl Ether)는 PMMA(Poly Methyl Methacrylate)를 생산하기 위한 석유화학 중간원료로 사용되는 것이 일반적이나, 무연휘발유 사용의 세계적인 추세에 힘입어 (정유산업에 있어서 그 수요가 날로 증가하고 있으며) 정유산업의 옥탄가 문제를 해결해 주는 유효적절한 수단으로 보급이 확대되고 있는 실정이다. 여기에서는 MTBE의 전반적인 특성 및 사용에 따른 효과 및 장단점을 소개하고자 한다.

• Journal of the Korean Applied Science and Technology
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• v.20 no.3
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• pp.243-250
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• 2003

Poly(methyl methacrylate)/clay nanocomposite particles with particle size of 275${\sim}$292 nm range were successfully prepared using emulsion polymerization. The content of montmorillonite based on the methyl methacrylate monomer was chosen as 30 wt.%. 2,2-azobis(isobuthylamidine hydrochloride) and n-dodecyltrimethylammonium chloride were used as an initiator and a surfactant in cationic emulsion system. Potassium persulfate and sodium lauryl sulfate were used as an initiator and a surfactant in anionic emulsion system. The evidence of intercalated /exfoliated structure of montmorillonite in the nanocomposite prepared in our experiment was confirmed by wide angle x-ray diffraction patterns of $d_{001}$ plane. Thermal behavior of nanocomposite was traced using DSC and TGA. It was found that the nanocomposite particle prepared by cationic emulsion system showed intercalated structured. We also found that the nanocomposite particle obtained from anionic emulsion system resulted in the fully exfoliated structure.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1924-1926
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• 2005

Poly(methyl methacrylate) (PMMA) is one of the promising representive of polymer gate dielectric for its high resistivity and sutible dielectric constant. PMMA (Mw=96700) films were prepared on p-Si by spin coating method. PMMA were coated compactively and flatly as observes by AFM. MIS(Al/PMMA/p-Si) structure was made and capacitance-voltage (C-V) and current-voltage (I-V) measurements were done with PMMA films for repeated annealing cycles at $100^{\circ}C$. 1-V measured at various delay times $(0{\sim}20sec)$ showed little change and the absence of hysteresis in the I-V characteristics with delay times, which eliminate the possibility of deep traps in the PMMA films. The observed thermal stability, smooth surfaces, dielectric constant, I-V behavior implies PMMA formed by spin coating can be used as an efficient gate dielectric layer in OTFTs.