• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.253-257
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• 2002

A new photoalignment material PNC, pole norbornene-2,3-dicarboxyolyl cholesterol, was synthesized and the electro-optical (EO) characteristics of the vortical-alignment (VA) liquid crystal display (LCD) photoaligned with UV exposure on the PNC surface were studied. EO characteristics of the photoaligned VA-LCD using a UV filter-less method was better than that of the UV filter method on the PNC surface for short UV exposure time. The response time of the photoaligned VA-LCD on the PNC surface without UV filter on the PNC surface is almost the same compared with the rubbing aligned VA-LCD.

• Macromolecular Research
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• v.17 no.12
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• pp.995-1002
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• 2009

Luminescent polynorbornene (PNB)/quantum dot (CdSe@ZnS; QD) composite nanorods and nanotubes were successfully prepared using anodic aluminum oxide (AAO) membranes of various pore sizes as templates. To protect QDs with high quantum yield from quenching during the phosphoric acid treatment used to remove the AAO templates, chemically stable and optically clear norbornene-maleic anhydride copolymers (P(NB-r-MA)) were employed as a capping agent for QDs. The amine-terminated QDs reacted with maleic anhydride moieties in P(NB-r-MA) to form PNB-grafted QDs. The chemical- and photo-stability of QDs encapsulated with PNB copolymers were investigated by photoluminescence (PL) spectroscopy. By varying the pore size of the AAO templates from 40 to 380 urn, PNB/QD composite nanorods or nanotubes were obtained with a good dispersion of QDs in the PNB matrix.

• Macromolecular Research
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• v.14 no.4
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• pp.424-429
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• 2006

The synthesis of a series of poly(POSS-NBE-b-MTD) copolymers was successfully accomplished, taking advantage of sequential, ring-opening, metathesis block copolymerization using $RuCl_2(=CHPh)(PCy_3)_2$ catalyst. By using cyclopentyl-POSS-norbornene (POSS-NBE) monomer as the first block in the block copolymer, living poly(POSS-NBE) with controlled molecular weight and narrow molecular weight distribution was produced. Then, poly(POSS-NBE-b-MTD) copolymers were successfully prepared, in which sequential monomer addition of methyltetracyclododecene (MTD) to the living poly(POSS-NBE) chain ends was utilized to achieve quantitative crossover efficiency. Characterization by $^1H$ NMR spectroscopy and GPC confirmed the high definition and structural integrity of the poly(PO$S-NBE-b-MTD) copolymers. Thermal properties-and morphologies of the POSS-containing block copolymer nanocomposites were also investigated by using thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and wide-angle X-ray scattering (WAXS).

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.333-333
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• 2006

We synthesized two novel polynorbornene derivatives, chiral poly(norbornene acid methyl ester) (C-PNME) and racemic poly(norbornene acid n-butyl ester) (R-PNME), which are potential low dielectric constant materials for applications in advanced microelectronic and display devices. Thin films of these polymers deposited on substrates were investigated by structural analyses using synchrotron grazing incidence X-ray scattering, specular reflectivity and ellipsometry. These analyses provided important information on the structure, electron density gradient across film thickness, chain orientation, refractive index and thermal expansion of the polymers in substrate-supported thin films. The structural characteristics and properties of the thin films were first dependent on the polymer chain' tacticity and further influenced by film thickness and thermal annealing.

• Polymer(Korea)
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• v.24 no.6
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• pp.751-756
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• 2000

The copolymerization of ethylene (E) and cycloolefin (CO) was carried out with rac-Et(Ind)$_2$ZrC $l_2$ and MMAO cocatalyst system to examine the effect of CO structure on catalytic behaviors and properties of copolymer (COC). Various cycloolefins such as norbornene (N), 5-phenyl-2-norbornene (PN) and 5-vinyl-2-norbornene (VN) were used as comonomers. With increasing [CO]/[E] feed ratio, the catalytic activity decreased while the glass transition temperature of copolymer increased. With analysis of the structure of E/VN copolymer by FT-IR and $^{l3}$C-NMR, it was found that the cyclic C=C bond of VN comonomer is selectively polymerized and the vinyl C=C bond remains unreacted. The resulting vinyl C=C bond attached into copolymer provided the functionalization moiety using glycidyl methacrylate.e.

• Polymer(Korea)
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• v.37 no.3
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• pp.356-361
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• 2013

Microcapsules of two different self-healing agents, 5-ethylidene-2-norbornene (ENB) and ENB with a crosslinker, surrounded by a melamine-urea-formaldehyde shell were manufactured. In this work, a red dye was incorporated into the self-healing agents as a tracer for better visual observations. It revealed that the incorporation of a red dye into self-healing agents did not disturb the formation of microcapsules from the examination of thermal resistance, particle size/size distribution and morphology of the resulting microcapsules. Releasing of self-healing liquid into the induced crack from ruptured microcapsules and filling between crack planes were observed using an optical microscope. Also observed was the reaction of filled healing agent with embedded Grubbs' catalyst in an epoxy coating layer.

• Macromolecular Research
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• v.12 no.5
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• pp.478-483
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• 2004

Two different diene monomers [dicyclopentadiene (DCPD) and 5-ethylidene-2-norbornene (ENB)] as self-healing agents for polymeric composites were microencapsuled by in situ polymerization of urea and formaldehyde. We obtained plots of the storage modulus (G') and tan $\delta$ as a function of cure time by using dynamic mechanical analysis to investigate the cure behavior of the unreacted self-healing agent mixture in the presence of a catalyst. Glass transition temperatures (T$\_$g/) and exothermic reactions of samples cured for 5 and 120 min in the presence of different amounts of the catalyst were analyzed by differential scanning calorimetry. Of the two dienes, ENB may have advantages as a self-healing agent because, when cured under same conditions as DCPD, it reacts much faster in the presence of a much lower amount of catalyst, has no melting point, and produces a resin that has a higher value of T$\_$g/. Microcapsules containing the healing agent were successfully formed from both of the diene monomers and were characterized by thermogravimetric analysis. Optical microscopy and a particle size analyzer were employed to observe the morphology and size distribution, respectively, of the microcapsules. The microcapsules exhibited similar thermal properties as well as particle shapes and sizes.

• Polymer(Korea)
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• v.24 no.4
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• pp.445-452
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• 2000

The copolymerization of ethylene (E) and norbornene (N) was examined by using various metallocene catalysts and modified-MAO(MMAO) cocatalyst. For $C_2$-symmetry catalysts such as rac-Et(Ind)$_2$ZrC $l_2$, M $e_2$Si(Ind)$_2$ZrC $l_2$, M $e_2$Si(Cp)$_2$ZrC $l_2$ and Cs-symmetrical iPr(FluCp)ZrC $l_2$ as well as CGC and di-bridged zirconocene, the effects of catalyst structure and [N]/[E] feed ratio on catalyst activity, thermal property and [N] content of copolymer (COC) was investigated. For rac-Et(Ind)$_2$ZrC $l_2$ catalyst of a constant [N]/[E] feed ratio, the appropriate conditions of [Al]/[Zr] mole ratio, polymerization temperature and cocatalyst structure were found to be 3000, 4$0^{\circ}C$, MMAO cocatalyst, respectively. As [N]/[E] feed ratio increased, the incorporation of norbornene to copolymer increased while, the activity of catalyst decreased except for iPr(FluCp)ZrC $l_2$ With consideration of catalyst activity as well as N content, it was found that rac-Et(Ind)$_2$ZrC $l_2$/MMAO system exhibited relatively high activity and controllable $T_{g}$. Monomer reactivity ratio was determined by Kelen-Tudos method..

• Macromolecular Research
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• v.15 no.5
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• pp.430-436
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• 2007

The dinuclear half-sandwich CGCs (constrained geometry catalyst) with a polymethylene bridge, $[Ti({\eta}^5 : {\eta}^1-indenyl)SiMe_2NCMe_3]_2(CH_2)_n]$[n = 6 (1) and 12 (2)], have been employed in the copolymerization of ethylene and norbornene (NBE). To compare the mononuclear metallocene catalysts; $Ti({\eta}^5 : {\eta}^1-2-hexylindenyl)SiMe_2NCMe_3$ (3), $(Cp^* SiMe_2NCMe_3)$Ti (Dow CGC) (4) and ansa-$Et(Ind)_2ZrCI_2$ (5), were also studied for the copolymerization of ethylene and NBE. It was found that the activity increased in the order: 1 < 2 < 3 < 5 < 4, indicating that the presence of the bridge between two the CGC units contributed to depressing the polymerization activity of the CGCs. This result strongly suggests that the implication of steric disturbance due to the presence of the bridge may playa significant role in slowing the activity. Dinuclear CGCs have been found to be very efficient for the incorporation of NBE onto the polyethylene backbone. The NBE contents in the copolymers formed ranged from 10 to 42%, depending on the polymerization conditions. Strong chemical shifts were observed at ${\delta}$42.0 and 47.8 of the isotactic alternating NBE sequences, NENEN, in the copolymers with high NBE contents. In addition, a resonance at 47.1 ppm for the sequences of the isolated NBE, EENEE, was observed in the $^{13}C-NMR$ spectra of the copolymers with low NBE contents. The absence of signals for isotactic dyad at 48.1 and 49.1 ppm illustrated there were no isotactic or microblock (NBE-NBE) sequences in the copolymers. This result indicated that the dinuclear CGCs were effective for making randomly distributed ethylene-NBE copolymers.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.200-200
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• 2006

Several polynorbornene or poly(norbornene-7-oxide) based functional block copolymers were synthesized by ring opening metathesis polymerization (ROMP) with good molecular weight and polydispersity control. Some representative functional groups in these polymers are a nitrobenzoyl group or ferrocene. These polymers were subjected to various chemical modification reactions to give other block copolymers that contain novel functionality such as amine, diazonium salt, and diazo groups. The resulting polymers were characterized by various techniques such as GPC, NMR, UV-VIS, AFM, and cyclovotammography (CV).