• Journal of Pharmaceutical Investigation
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• v.22 no.3
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• pp.237-240
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• 1992

A series of biodegradable block copolymers consisting of $poly({\gamma}-benzyl\;L-glutamate)$ (PBLG) and poly(ethylene oxide) (PEO)-lactoselactone were prepared by polymerization of PEO-lactoselactone and ${\gamma}-benzyl$ L-glutamate-N-carboxyanhydride and characterized by IR and NMR. From circular dichroism measurements, it was found that the polymers exist in the ${\alpha}-helical$ conformation. Block copolymer microspheres were prepared by solvent-extraction-precipitation method for their primary evaluation for medical and biological applications.

• Textile Coloration and Finishing
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• v.5 no.3
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• pp.194-205
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• 1993

Plasma polymerization in prepared glow discharge was carried out to improve the bathochromic of dyed PET fabrics by using silicon containing vinyl monomer in plasma polymerization equipment which consists of a pair of electrodes was connected to the 13.56MHz RF generator. The optimum condition for the bathochromic effect was investigated on various plasma polymeriztion parameters. By plasma polymerization used silicon containing vinyl monomer, the bathochromic of dyed PET fabrics was very enhanced. The optimum conditions on this equipment were as follows ; electrode distance : 3cm, discharge output : 60W, gas pressure : 0.3 Torr, monomer flow rate : 30㎤/min. plasma polymerization time : 60sec. The apparent strength of plasma polymerized PET fabrics was increased about 40∼47% with decreasing about 3 of L value.

• Macromolecular Research
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• v.17 no.3
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• pp.174-180
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• 2009

Chemical modification of titanium/titanium oxide (Ti/$TiO_2$) substrates has recently gained a great deal of attention because of the applications of Ti/$TiO_2$-based materials to biomedical areas. The reported modification methods generally involve passive coating of Ti/$TiO_2$ substrates with protein-resistant materials, and poly(ethylene glycol) (PEG) has proven advantageous for bestowing a nonbiofouling property on the surface of Ti/$TiO_2$. However, the wider applications of Ti/$TiO_2$ based materials to biomedical areas will require the introduction of biologically active moieties onto Ti/$TiO_2$, in addition to nonbiofouling property. In this work, we therefore utilized surface-initiated polymerization to coat the Ti/$TiO_2$ substrates with polymers presenting the nonbiofouling PEG moiety and subsequently conjugated biologically active compounds to the PEG-presenting, polymeric films. Specifically, a Ti/$TiO_2$ surface was chemically modified to present an initiator for atom transfer radical polymerization, and poly(ethylene glycol) methacrylate (pEGMA) was polymerized from the surface. After activation of hydroxyl groups of poly(pEGMA) (pPEGMA) with N,N'-disuccinimidyl carbonate, biotin, a model compound, was conjugated to the pPEGMA films. The reactions were confirmed by infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle goniometry, and ellipsometry. The biospecific binding of target proteins was also utilized to generate micropatterns of proteins on the Ti/$TiO_2$ surface.

• Polymer(Korea)
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• v.39 no.3
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• pp.461-467
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• 2015

This paper reports the combined effects of the triblock copolymer surfactant poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEG-PPG-PEG) and imidazole on the opto-electrical and mechanical properties of poly(3,4-ethylenedioxythiophene) (PEDOT)-based thin films prepared via vapor phase polymerization (VPP) using ferric p-toluenesulfonate as a catalyst. Various PEDOT-based thin films were synthesized using PEG-PPG-PEG and imidazole alone and in combination to compare and correlate their effects on film properties. The improved conductivity of the PEDOT films was higher than $1300S{\cdot}cm^{-1}$ when the surfactant and imidazole were used together. The PEG-PPG-PEG chain length was also varied to identify the best conditions for the VPP-based preparation of PEDOT thin films.

• Polymer(Korea)
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• v.31 no.6
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• pp.550-554
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• 2007

Atom transfer radical polymerization (ATRP) has been widely used in bioconjugation as it is an efficient and facile method to prepare polymers with pre-designed structures. Quite often, bioconjugation with proteins employs primary amines in proteins as a functional group to attach an initiator. When 2-bromoisobutryl bromide, the most widely used precursor for ATRP initiator, is used, ${\alpha}-halo$ amide initiating groups are formed in the proteins, which are known to exhibit slow initiation behavior in the ATRP process. Here we studied the ATRP of [poly(ethylene glycol)methyl ether] methacrylate (PEGMA) using amide-based initiator. PEGMA differs for both the nature and size of the polymer side branches and shows good solubility in water and a property that made it an ideal candidate for biomaterials. While normal ATRP produced ill-defined p(PEGMA) with amide based initiators, the halogen exchange method and the external additional of deactivator effectively improved the control of ATRP of PEGMA.

• Polymer(Korea)
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• v.28 no.4
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• pp.344-351
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• 2004

Poly(ethylene glycol)-based diblock and triblock polyester copolymers stimulating to temperature were studied as injectable biomaterials in drug delivery system because of their nontoxicity, biocompatibility and biodegradability. We synthesized the diblock copolymers consisting of methoxy poly(ethylene glycol) (MPEG) (M$_{n}$=750 g/mole) and poly($\varepsilon$-caprolactone) (PCL) by ring opening polymerization of $\varepsilon$-CL with MPEG as an initiator in the presence of HCl . Et$_2$O. The aqueous solution of synthesized diblock copolymers represented sol phase at room temperature and a sol to gel phase transition as the temperature increased from room temperature to body temperature. To confirm the in vivo gel formation, we observed the formation of gel in the mice body after injection of 20 wt% aqueous solution of each block copolymer. After 2 months, we observed the maintenance of gel without dispersion in mice. In this study, we synthesized diblock copolymers exhibiting sol-gel phase transition and confirmed the feasibility as biomaterials of injectable implantation.n.

• Macromolecular Research
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• v.17 no.4
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• pp.250-258
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• 2009

One-step seeded polymerization was used to prepare $7{\sim}10{\mu}m$ of crosslinked monodisperse spheres with four crosslinking agents using $4.68{\mu}m$ poly(methyl methacrylate)(PMMA) seed particles in aqueous-alcoholic media in the absence of the swelling process. The crosslinking agents used were ethylene glycol dimethacrylate(EGDMA), allyl methacrylate(AMA), 1,6-hexanediol diacrylate(HDDA) and trimethylolpropane trimethacrylate(TMPTMA). The effects of the type and concentration of the crosslinking agents on the swelling, pore size, thermal property of the networks and morphology of the particles were studied. The chemical structures and concentrations of the crosslinking agents affected both the swelling ratio and the porosity of the networks. In addition, the chemistry of the reactive vinyl group and chain length of the crosslinking agents affected the stability of the monodisperse particles of the ultimate morphology.

• Macromolecular Research
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• v.13 no.2
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• pp.102-106
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• 2005

Poly(methyl methacrylate) (PMMA)/sodium montmorillonite (Na-MMT) nanocomposites were prepared with a novel method utilizing a macroazoinitiator (MAI). To induce the intergallery polymerization of methyl methacrylate (MMA), the MAI containing a po1y(ethylene glycol) (PEG) segment was intercalated between the lamellae of Na-MMT and swelled with water to enhance the diffusion of MMA into the gallery. The structure of the nanocomposite was examined using X-ray diffraction and transmission electron microscopy, and the thermal properties were examined using differential scanning calorimetry and thermogravimetry. The PMMA/Na-MMT nanocomposite prepared by intergallery polymerization showed a distinct enhancement of its thermal properties; an approximately $30^{\circ}C$ increase in its glass transition temperature and an $80\sim100^{\circ}C$ increase in its thermal decomposition temperature for a $10\%$ weight loss.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.226-226
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• 2006

Ethylene was polymerized with a catalyst having sterically hindered pentamethylcyclopentadienyl ligand, $Cp^{\ast}_{2}ZrCl_{2}/MAO$, and the polymerization mixture were treated with dry oxygen (oxidative workup) to produce hydroxyl-terminated polyethylenes (PE-OH). Polyethylene-block-Poly (${\Box}-caprolactone$) was synthesized from PE-OH and ${\cdot}\^{A}-caprolactone$A by using stannous octoate as a catalyst for ring opening polymerization of ${\cdot}\^{A}-caprolactone$. Polyethylene-block-Poly(methyl methacrylate) was obtained by transforming the hydroxyl-terminated polyethylenes to macroinitiators for atom transfer radical polymerization (ATRP) and by reacting them with MMA.

• Macromolecular Research
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• v.13 no.3
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• pp.229-235
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• 2005

Various alkoxyamine initiators for nitroxide mediated radical polymerization (NMRP) were prepared in high yields by a simple substitution reaction of nitroxide anions with benzyl bromide. The required nitroxide anions were easily generated by treating either nitroxide free radicals or hydroxy amine with an alkali metal such as sodium or potassium in THF. This method is both practical and efficient, since the ionic conditions prevent other side reactions from occurring, such as the self-coupling or oligomerization reactions that are observed in the case of radical trapping conditions. To demonstrate the utility of the resulting alkoxyamine initiators, end- and telechelic-alkoxyamine PEG macroinitiators derived from the alkoxyamines were synthesized by a simple chemical modification, and used for the preparation of PEG-b-PS and PS-b-PEG-b-PS block copolymers by NMRP.