• Elastomers and Composites
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• v.51 no.2
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• pp.138-146
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• 2016

It is an inconvenience for silica nano-particles to dry again when using it in that they cohere each other through moisture in the air. Acrylamide groups were introduced to improve such inconvenience and copolymerized with silica nano-particles and then we copolymerized again with polyamic acid in order to increase thermal characteristic. Amide block copolymers were prepared using silica and (3-mercaptopropyl) trimethoxysilane (MPTMS) with a siloxane group, using 2,6-Lutidine as a catalyst. Amide block polymers and copolymers were synthesized via ATRP after brominating pyromellitic dianhydride (PMDA) and polyamic acid of methylene diphenyl diamine (MDA), using ${\alpha}$-bromo isobutyryl bromide. Characteristic peaks of copolymer with amide and imide groups and patterns of amorphous polymers were researched by FT-IR and XRD analyses and the analysis of surface characteristic groups was conducted via XPS. A change in thermal properties was examined through DSC and TGA and solubility for solvents was also researched.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.338-338
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• 2011

최근 FPD (Flat Pannel Display) 시장이 커짐에 따라 고효율, 저비용 제작 공정이 화두로 떠오르고 있다. ELA (Excimer Laser Annenling)을 이용한 LTPS (Low Temperature Poly Silicon) 공정은 mobility와 전류 점멸비 등에서 장점을 가지지만, 고비용, 대면적과 short-range에서 uniformity가 어렵다는 단점이 있다. 이를 극복하기 위한 방법으로 dLTA (diode Laser Thermal Annealing) 공정에 대한 연구가 진행되고 있다. 본 연구에서는 Flexible Display을 만들기 위한 방법으로 dLTA 공정을 진행하였다. 이 방법은 PI (Poly imide) 기판 위에 a-Si을 ICP CVD로 증착시킨 후, Diode Laser (980 nm)를 이용한 annealing을 통하여 a-Si이 poly-Si으로 결정화가 되는 것을 확인하였고, 에너지 조사량에 따른 grain boundary와 grain size을 통하여 비교 분석하였다. 실험 결과 ELA 공정을 이용한 것과 버금가는 실험 결과를 얻을 수 있었다.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.493-498
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• 1995

Ultrathin networks of itaconic acid copolymers and poly(allylamine) were produced by a Langmuir-Blodgett (LB) technique employing a double-chain amine as a monolayer template which was subsequently removed by extraction after thermal crosslinking. Itaconic acid copolymers used were copoly (itaconic acid-ethyl vinyl ether) and copoly (itaconic acid-n-butyl vinyl ether). The polyion-complexed monolayers of three components consisting of template amine, itaconic acid copolymer and poly (allylamine) were formed at the air-water interface. The Langmuir film properties have been studied by the surface pressure-area isotherm and fluorescence microscopy. The monolayers were transferred on solid substrates and were characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). Two-dimensional polymer networks were formed through imide or amide linkages by heat treatment under vacuum. The heat-treated films were extracted with chloroform after immersion in aq. sodium chloride to remove the template amines. SEM observation of a LB film on a porous fluorocarbon membrane filter with pore diameter of 0.1 μm showed covering of the pores by six layers in the polyion complex state.

• Membrane Journal
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• v.28 no.4
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• pp.221-232
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• 2018

The silica containing carbon ($C-SiO_2$) membranes were fabricated using poly(imide siloxane)(Si-PI) and polyvinylpyrrolidone (PVP) blended polymer. The characteristics of porous carbon structures prepared by the pyrolysis of polymer blends were related with the micro-phase separation behaviors of the two polymers. The glass transition temperatures ($T_g$) of the mixed polymer blends of Si-PI and PVP were observed with a single $T_g$ using differential scanning calorimetry. Furthermore, the nitrogen adsorption isotherms of the $C-SiO_2$ membranes were investigated to define the characteristics of porous carbon structures. The $C-SiO_2$ membranes derived from Si-PI/PVP showed the type IV isotherm and possessed the hysteresis loop, which was associated with the mesoporous carbon structures. For the molecular sieving probe, the $C-SiO_2$ membranes were prepared with the ratio of Si-PI/PVP and the pyrolysis conditions, such as the pyrolysis temperature and the isothermal times. Consequently, the $C-SiO_2$ membranes prepared by the pyrolysis of Si-PI/PVP at $550^{\circ}C$ with the isothermal time of 120 min showed the $O_2$ permeability of 820 Barrer ($1{\times}10^{-10}cm^3(STP)cm/cm^2{\cdot}s{\cdot}cmHg$) and $O_2/N_2$ selectivity of 14.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.3074-3080
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• 2011

We synthesized three novel poly(norbornene bisimide)s by ring opening metathesis polymerization (ROMP) and subsequent hydrogenation. Their thermal, mechanical and optical properties were investigated with TGA, DMA, UV-Vis spectrometer, and optical reflectometer. The new polymers showed high glass transition temperatures over $260^{\circ}C$ and good thermal stability with 5% wt-loss temperature higher than $390^{\circ}C$. When solvent casted, they yielded optically transparent and dimensionally stable films with a relatively low coefficient of thermal expansion of about 50 ppm $K^{-1}$. Therefore, the bisimide moieties substantially enhanced thermal and dimensional stabilities, as compared with normal ROMP-prepared polynorbornene films. Though the water uptake was increased to 0.6 wt-%, this water uptake is still considerably lower than that for polyethersulfones (1.4 wt-%) or polyimides (2.0 wt-%). Hence, the new poly(norbornene bisimide)s may become attractive candidates for flexible substrates of optoelectronic devices such as displays and photovoltaic solar cells.

• Polymer(Korea)
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• v.37 no.4
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• pp.420-430
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• 2013

Polymer blends were prepared by solution blending poly(amic acid) (PAA) and poly(o-hydroxy amide) (PHA) having imide groups in the main chain. The polymers and their blends were characterized by using FTIR, FT NMR, DSC, TGA, SEM, XRD, UTM, and LOI. The solubility study revealed that the blends were readily soluble in aprotic solvents such as DMF, DMAc, DMSO, and NMP. The maximum weight loss of the blends occurred in the range of $578-645^{\circ}C$, and the maximum weight loss temperature increased with increasing the PHA content. The PBO/PI blends showed relatively high char yields (i.e. 56-69 wt%). The LOI values of the blends were in the range of 24.5-28.1% and increased with increasing the PHA content. The initial modulus and tensile strength of the blends increased by 57 to 121% and by 67 to 107%, respectively, compared to the values of PAA. Especially the initial modulus and tensile strength of the PHA/PAA=2/8(wt/wt) showed the highest values of 4.87 GPa and 108 MPa, respectively. The PHA domains of $0.03-0.1{\mu}m$ in their size were more or less uniformly dispersed. The interfacial adhesion between PAA and PHA was found to be good.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.172-175
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• 2004

• Proceedings of the Membrane Society of Korea Conference
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• 2002.05a
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• pp.62-64
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• 2002

No Abstract, See Full-text

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.176-180
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• 2004

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.9-13
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• 1998

A number of papers concerning the preparation and physical properties of thermotropic polyurethanes have been reported,$^{1.2}$ since thermotropic polyurethanes were first reported by Iimura and coworkers.$^3$ We have been studying the synthesis of thermotropic para-type aromatic polyurethanes containing alkylene spacers.$^{4.7}$ .(omitted)