• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.156-157
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• 2006

Quasi-living polymerization conditions for the copolymerization of ethylene and functionalized norbornenes can be achieved by using an initiator system comprising $[N-(2,6-diisopropylphenyl)-2-(2,6-diisopropylphenylimino)-propanamidato-{\kappa}^2N,O]Ni({\Box}^1-CH_2Ph)(PMe_3)\;and\;Ni(COD)_2$. It is possible with this polymerization system to obtain block-copolymer and tapered structures. The latter form microdomains similar to those of standard block co-polymers. The mechanism of the reaction will also be discussed.

• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.35-35
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• 1996

• Proceedings of the Optical Society of Korea Conference
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• 1995.06a
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• pp.161-168
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• 1995

Nonlinear optical absorption in solid films of poly(3-octyl thiophene) (P3OT) sensitized with methanofullerene was inverstigated for wacelengths from 620 to 960nm. The nonlinear absorption is ehnanced over that in either of the component materials by more than two orders orders of magitude at 760nm. The large nonlinearity results from effient photoinduced interm olecular charge transfer from P3OT to methanofullerene, followed by absorption in the charge separated excited state. P3OT/fullerene films are promising as reverse saturable absorbers and the optical limiting performance is demonstrated at 760nm.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.62-62
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• 2006

Based on the redox couples of a nitroxide radical, organic radical polymers were utilized as the electrode-active or charge-storage component for a secondary battery. We call a battery composed of the radical polymer electrode as "organic radical battery". Organic radical battery has several advantages: high capacity, high power-rate performance, long cycle ability, and environmentally-benign features. Synthesis and electrochemical studies of nitroxide polymers are described. Battery fabrication and cell performance are also reported.

• Elastomers and Composites
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• v.45 no.2
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• pp.74-79
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• 2010

In this review, the properties of buckminsterfullerene and its organic and polymeric reactions were focused. In addition, polymer blending with $C_{60}$ will be briefly introduced. As soon as $C_{60}$ was discovered, chemists put their efforts to explore its reactivity with other compounds. The knowledge of the organic reactions with $C_{60}$ was extended to construct different types of fullerene polymers such as side chain fullerene polymers, main chain fullerene polymers, star shaped fullerene polymers, and dendritic fullerene polymers.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.326-326
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• 2006

The combination of living anionic and coordination polymerization techniques enabled to synthesize the polystyrene-b-polyisoprene-b-poly (butyl isocyanate) triblock polymers. Their microphase-separated structures were zig-zag structures for high ${\phi}_{PIC}$ samples, and hockey-puck structures were also observed. The phase diagram for PSt-b-PIp-b-PIC rod-coil polymers was different from that for PS-PBd-PMMA triblock polymers, and it was found that ${\phi}_{PIC}$ was the important factor to determine the microphase-separated structures.

• Economic and Environmental Geology
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• v.32 no.3
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• pp.307-315
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• 1999

Four organic polymers were mixed with mothmorillonite. Two cationic polymers a hi로 molecular weight polyacrylamide (494C) and a low molecular weight polymer (587C).Two anionic polymers include a high molecular weight polymer (aerotil). Each clay supension series were allowed to stand for 24 hours and were centrifuged, and the clay plugs were washed and dried. The dried samples investigated by XRD, IR and CEC measurement. The suspended clay containing anionic polymers was not flocculated at any concentratuons of polymer. But the suspendions containing two cationic polymers were rapidly flocculated at almost all concentrations. the d(001) spacings of Na-montmorillonite after being with cationic polymer 587C show about 15$\AA$ suggesting the polymers may have entered the interlayer spaces. The polymer 494C-treated sample produced double peaks of about 12 and 15$\AA$ in XRD. It indicates that the high molecular weight polymer. And cationic polymer 494C may be adsorbed mainy on the outside surface of clay, and some polymers may peretrate into olny interlayers in the margin of montmorillonite particles because of its high molecular weught. CEC of polumer 587-treated sample was reduecd mmarkedly suggesting polymer blocks CEC sites. The d(001) spacings of Ca-montmorillonite after being treated with cationic polymers show about 15$\AA$ suggesting that the interlayer spaces have not been expanded. In the experiment using a dilute Ca-bearing solution, the suspended caly containinf anionic polymers was flocculated. The results indicate that the flocculation behavior of montmorillonite-polymer supension depends on not only polymer properties such as concentration, electric charge and molecular weight but also compositions of solvent.

• Biomaterials Research
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• v.22 no.4
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• pp.249-258
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• 2018

Background: Mucoadhesive polymers, which may increase the contact time between the polymer and the tissue, have been widely investigated for pharmaceutical formulations. In this study, we developed a new polysaccharide-based mucoadhesive polymer with thermogelling properties. Methods: Hexanoyl glycol chitosan (HGC), a new thermogelling polymer, was synthesized by the chemical modification of glycol chitosan using hexanoic anhydride. The HGC was further modified to include thiol groups to improve the mucoadhesive property of thermogelling HGC. The degree of thiolation of the thiolated HGCs (SH-HGCs) was controlled in the range of 5-10% by adjusting the feed molar ratio. The structure of the chemically modified polymers was characterized by $^1H$ NMR and ATR-FTIR. The sol-gel transition, mucoadhesiveness, and biocompatibility of the polymers were determined by a tube inverting method, rheological measurements, and in vitro cytotoxicity tests, respectively. Results: The aqueous solution (4 wt%) of HGC with approximately 33% substitution showed a sol-gel transition temperature of approximately $41^{\circ}C$. SH-HGCs demonstrated lower sol-gel transition temperatures ($34{\pm}1$ and $31{\pm}1^{\circ}C$) compared to that of HGC due to the introduction of thiol groups. Rheological studies of aqueous mixture solutions of SH-HGCs and mucin showed that SH-HGCs had stronger mucoadhesiveness than HGC due to the interaction between the thiol groups of SH-HGCs and mucin. Additionally, we confirmed that the thermogelling properties might improve the mucoadhesive force of polymers. Several in vitro cytotoxicity tests showed that SH-HGCs showed little toxicity at concentrations of 0.1-1.0 wt%, indicating good biocompatibility of the polymers. Conclusions: The resultant thiolated hexanoyl glycol chitosans may play a crucial role in mucoadhesive applications in biomedical areas.

• Carbon letters
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• v.2 no.3_4
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• pp.202-211
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• 2001

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.301-302
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• 2003

Recently, synthetic polymers containing units of carbohydrate derivatives with pendatnt functional groups have been much studied. The polymers should be able to be used drug carriers and scaffold for tissue engineering, because of their nontoxicity, biocompatibility, and biodegradability.$\^$1-6/ During the last three decades, various polyfunctional polymers, e.g. polyhydroxypolyamides and polyesteramides, based on carbohydrates have been reported and synthesized by condensation polymerization between sugar derivative and diamines, although it could be done via complicated reaction routes going through protecting.$\^$1-6/ (omitted)