• Macromolecular Research
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• v.17 no.6
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• pp.424-429
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• 2009

In this study, we demonstrate that the biological unnatural amino acid incorporation method can be utilized in vivo to synthesize an alkyne-terminated telechelic protein, Synthesis of terminally-functionalized polymers such as telechelic polymers is recognized to be important, since they can be employed usefully in many areas of biology and material science, such as drug delivery, colloidal dispersion, surface modification, and formation of polymer network. The introduction of alkyne groups into polymeric material is particularly interesting since the alkyne group can be a linker to combine other materials using click chemistry. To synthesize the telechelic recombinant protein, we attempted to incorporate the L-homopropargylglycine into the recombinant GroES fragment by expressing the recombinant gene encoding Met at the codons for both N- and C-terminals of the protein in the Met auxotrophic E. coli via Hpg supplementation. The Hpg incorporation rate was investigated and the incorporation was confirmed by MALDI-TOF analysis of the telcchelic recombinant protein.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.463-464
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• 2007

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• Textile Coloration and Finishing
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• v.30 no.2
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• pp.130-140
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• 2018

In the bio-synthesis of poly(3-hydroxybutyrate)(PHB), which is a kind of poly(3-hydroxyalkanoate)(PHA), aimed to control the low molecular weight of PHB and obtain a telechelic PHB. As a result of incubation of R. eutropha at $30^{\circ}C$ with ethylene glycol added as a chain transfer agent, PHB content on the dry cell weight increased up to 24h, however, it decreased after that, and the molecular weight of PHB increased from 9h to 12h, and then, decreased up to 72h. The decrease of the content and the molecular weight of PHB indicates that PHB was decomposed as an energy source in bacterial cells and was incorporated into metabolic pathways. $^1H-NMR$ of the obtained PHB after incubation for 72h was measured to determine the terminal groups of the PHB during incubation. As the results of $^1H-NMR$ measurement, the peaks derived from ethylene glycol in both terminals of PHB were observed. Which indicate that the terminal reaction was caused by the addition of ethylene glycol, and that telechelic PHB having hydroxyl group at the both terminals where molecular weight was controlled was successfully synthesized.

• Polymer Science and Technology
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• v.3 no.6
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• pp.465-474
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• 1992

지금까지 우리는 환상 단량체(cyclic monomer)를 이용한 macromonomer의 다양한 합성 방법론에 대해 고찰해 왔다. 리빙 개환 중합(iving ring-opening polymerization)이 좁은 분자량 분포 및 예견할 수 있는 well-defined 구조를 갖는 macromonomer들을 합성할 수 있는 최상의 방법임은 주지의 사실이다. 또한 이렇게 합성된 macromonomer들을 이용한 graft 공중합체의 합성은 이미 언급한 바와 같이 다방면에 사용되고 있다. 다음으로 중요한 점은 많은 과학자들이 과학적 용어(scientific term)의 사용에 있어서 사용자들에게 많은 혼돈을 주고 있다는 사실이다. 예를들면 macromonomer는 Macromer$^{(R)}$ 혹은 macromolecular monomer등과 같은 의미이지만 어느 한가지로 통일되지 못하고 사용되고 있는 실정이다. 덧붙이자면 macromonomer는 기능화된 고분자(functionalized polymer) 혹은 넓은 의미의 'telechelic polymer'의 범주에 속한다. 본래 telechelic polymer란 분자 말단에 두개의 반응성기를 갖는 고분자나 oligomer를 일컫는 말로서 기능성 고분자(functionalized polymer)의 범주에 속한다. 이러한 사실들을 고려해 볼때 macromonomer는 중합이 일어날 수 있는 반응성 기를 가진 기능성 고분자 혹은 telechelic 고분자이다. 또한 많은 사람들이 macroinitiator와의 상이점을 구별치 못하는 경우가 있다. 물론 macroinitiator는 보통 block 공중합체를 제조하는데 이용되고 있는 반면 macromonomer는 graft 공중합체 합성에 사용되는 고분자 또는 oligomer이다.

• Proceedings of the Korean Fiber Society Conference
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• 1986.06a
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• pp.8-8
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• 1986

• Polymer(Korea)
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• v.29 no.3
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• pp.271-276
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• 2005

Polypropylene (PP)/montmorillonite (MMT) nanocomposites were prepared by melt mixing methods. MMT modified by dimethyl hydrogenated tallow 2-ethylhexyl ammonium (Cloisite 15A) was used. Polyolefine oligomer with telechelic OH groups was used as a compatibilizer. The degree of dispersion of MMT in the nanocomposites was measured by X-ray diffractometer and transmission electron microscope (TEM) images. MMT was well exfoliated when the contents of compatibilizer was 25 phr. The thermal stability that observed by thermogravimetric analysis (TGA) increased with the contents of MMT increased up to 5 phr. The complex viscosities and storage moduli of PP nanocomposites enhanced as the contents of compatibilizer decreased and those of MMT increased.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.5
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• pp.461-467
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• 2012

Multi-block sulfonated poly (arylene ether sulfone) (SPES) membranes were synthesized by post-sulfonation and its properties characterized. Two types of oligomers, F-terminated and OH-terminated telechelic oligomers, were synthesized by controlling the feed ratio of dihydroxyl- and difluoro-monomers. Their number of repeating unit (X and Y) was analyzed by GPC and $^1H$ NMR. Copolymerization with F-terminated and OH-terminated telechelic oligomers via nucleophilic aromatic substitution, gave high-molecular-weight multi-block PESs. Each block length was controlled to have different values with X5Y10, X10Y10, X20Y10 and X20Y20. Successful polymerization and its successful sulfonation was confirmed by GPC and $^1H$ NMR. RH dependence of proton conductivity of multi-block SPES membranes was comparable to that of Nafion 212 at high RH conditions.

• Textile Coloration and Finishing
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• v.10 no.5
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• pp.32-38
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• 1998

Glycolides were polymerized by PPG or Pluronic(PN) to give A-B-A block copolyesters consisting of polyglycolide(A) and polypropylene glycol(B) or polyglycolide(A) and PN (B). Lactones were easily copolymerized with polyethers by ester interchange reaction even in the absence of catalyst. It is because PPG and PN are telechelic polyethers having hydroxy groups on their both ends. When the feed ratio of PPG(M$_{n}$=4,000) and PN(M$_{n}$=11,500) were over 5 and 10 wt% .elative to glycolide, respectively, the polymerization of glycolide took place from the terminus hydroxy groups of PPG or PN to produce the desired A-B-A block copolymers in high yields. The molecular weights of the copolymers, which estimated from the monomer conversions and the feed ratios of PPG and PN, could be controlled by changing the kind of terminus hydroxy of polyether and the feed molar ratio of PPG and PN. PN.

• Macromolecular Research
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• v.9 no.2
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• pp.84-91
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• 2001

Both A-B-A triblock and multiblock copoly(ester-ether)s consisting of poly(L-Lactide) and poly(oxyethylene-co-oxypropylene) were prepared and characterized. The preparation of the triblock copolymer was done by ring-opening copolymerization of L-lactide with a commercially available telechelic copolyether, Pluronic$\^$TM/(PN) by catalysis of stannous octanoate. The molecular weight and unit composition of the produced copolymers were successfully controlled by changing the L-lactide/PN ratio in feed. However, a high molecular weight copolymer incorporating PN in large amount was not obtained because the molecular weight of the resulting copolymer was limited at a high L-lactide/PN composition. The multiblock copolymer was synthesized by the copolycondensation of oligo(L-lactic acid) prepared by thermal dehydration of L-lactic acid, PN, and dodecanedioic acid as carboxyl/hydroxyl adjusting agent. This polycondensation proceeded by catalysis of stannous oxide to give multiblock copolymers with high molecular weight and wide range of compositions.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.271-271
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• 2006

The present article describes a novel method of preparing the sulfonated polysulfone-based PEMs for DMFC, which are excellent in film quality, proton conductivity, methanol impermeability and mechanical properties. No depression in film quality or difficulty in film preparation is observed, even though sulfonated group of the PEMs are kept as high as 70 mol %. Allyl-terminated cooligo-PESs containing the organic sulfonate groups were solvent-cast into films and then thermally treated for cross-linking. Cross-linked sulfonated polysulfone-based PEMs gave unprecedented reduction of methanol cross-over and high ionic conductivity through in-situ thermal polymerization and cross-linking of telechelic sulfonated sulfone oligomers during a membrane preparation.