• Proceedings of the PSK Conference
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• 2002.10a
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• pp.408.2-409
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• 2002

The aim of this study is to prepare biodegradable microspheres without use of any kind of surfactants or emulsifiers for a novel sustained delivery carriers of protein drugs. Poly(e-caprolactone)/poly(ethylene glycol)/poly(e-caprolactone) (CEC) triblock copolymer was synthesized by ring-opening of e-caprolactone with dihydroxy poly(ethylene glycol) and was used to make surfactant-free microspheres. (omitted)

• Macromolecular Research
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• v.16 no.7
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• pp.609-613
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• 2008

Poly($\varepsilon$-caprolactone)-poly(ethylene glycol)-poly($\varepsilon$-caprolactone) (PCL-PEG-PCL) multiblock copolymers at various hydrophobic-hydrophilic ratios were successfully synthesized by the chain extension of triblock copolymers through isocyanate (hexamethylene diisocyanate). Biodegradable films were prepared from the resulting multiblock copolymers using the casting method. The mechanical properties of the films were improved by chain extension of the triblock copolymers, whereas the films prepared by the triblock copolymers were weak and brittle. Atomic force microscopy (AFM) of the multiblock copolymer film showed that the hydrophilic PEG had segregated on the film surface. This is consistent with the observed contact angle of the films.

• Polymer(Korea)
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• v.25 no.3
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• pp.421-426
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• 2001

11-Aminododecanoic acid, to insert the functional group of -COOH reacted with the end group of poly($\varepsilon$-caprolactone) diol, and cetyltrimethylammonium bromide (CTMA), to increase the d-spacing of Montmorillonite (MMT), were intercalated into $Na^+;_-$MMT. The modified MMT was reacted with poly(${varepsilon}-caprolactone$) diol ($M_n{=2000$) in THF solution at $80^{\circ}C$ for 4 hrs. After reaction, poly(${varepsilon}-caprolactone$) ($M_n{=80000$) was mixed into the solution for 12 hrs. To prepare the PCL/clay nanocomposite film this solution was cast into the silicon mold at $60^{\circ}C$ in vacuum oven for 6 hrs. From the results of XRD and TEM, it was found that the exfoliated PCL/clay nanocomposite were prepared. The effects of the amount of MMT on the mechanical properties and thermal properties of PCL/clay nanocomposites have been investigated by tensile tester and DSC. Because the MMT was dispersed homogeneously in PCL matrix, the Young's modulus of the nanocomposite were found to be excellent. However, MMT dispersed in PCL matrix had almost no effect on the tensile strength of the composites. The crystallization temperature of PCL increased in proportion to 3 wt% MMT in the PCL matrix.

• Macromolecular Research
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• v.15 no.7
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• pp.623-632
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• 2007

Thermosensitive nanoparticles were prepared via the self-assembly of two different $poly({\varepsilon}-caprolactone)$-based block copolymers of poly(N-isopropylacrylamide)-b-$poly({\varepsilon}-caprolactone)$ (PNPCL) and poly(ethylene glycol)-b-$poly({\varepsilon}-caprolactone)$ (PEGCL). The self-aggregation and thermosensitive behaviors of the mixed nanoparticles were investigated using $^1H-NMR$, turbidimetry, differential scanning microcalorimetry (micro-DSC), dynamic light scattering (DLS), and fluorescence spectroscopy. The copolymer mixtures (mixed nanoparticles, M1-M5, with different PNPCL content) formed nano-sized self-aggregates in an aqueous environment via the intra- and/or intermolecular association of hydrophobic PCL chains. The microscopic investigation of the mixed nanoparticles showed that the critical aggregation concentration (cac), the partition equilibrium constants $(K_v)$ of pyrene, and the aggregation number of PCL chains per one hydrophobic microdomain varied in accordance with the compositions of the mixed nanoparticles. Furthermore, the PNPCL harboring mixed nanoparticles evidenced phase transition behavior, originated by coil to the globule transition of PNiPAAm block upon heating, thereby resulting in the turbidity change, endothermic heat exchange, and particle size reduction upon heating. The drug release tests showed that the formation of the thermosensitive hydrogel layer enhanced the sustained drug release patterns by functioning as an additional diffusion barrier.

• Archives of Pharmacal Research
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• v.26 no.6
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• pp.504-510
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• 2003

The aim of this study is to prepare biodegradable microspheres without the use of surfactants or emulsifiers for a novel sustained delivery carriers of protein drugs. A poly($\varepsilon$-caprolactone)/poly(ethylene glycol)/poly($\varepsilon$-caprolactone) (CEC) triblock copolymer was synthesized by the ring-opening of $\varepsilon$-caprolactone with dihydroxy poly (ethylene glycol) to prepare surfactant-free microspheres. When dichloromethane (DCM) or ethyl formate (EF) was used as a solvent, the formation of microspheres did not occur. Although the microspheres could be formed prior to lyophilization under certain conditions, the morphology of microspheres was not maintained during the filtration and lyophilization process. Surfactant-free microspheres were only formed when ethyl acetate (EA) was used as the organic solvent and showed good spherical micro-spheres although the surfaces appeared irregular. The content of the protein in the micro-sphere was lower than expected, probably because of the presence of water channels and pores. The protein release kinetics showed a burst release until 2 days and after that sustained release pattern was showed. Therefore, these observations indicated that the formation of microsphere without the use of surfactant is feasible, and, this the improved process, the protein is readily incorporated in the microsphere.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.247-255
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• 1992

Polystyrene-poly(caprolactone) (PS-PCL) block copolymer was synthesized from macroazoinitiator, and its compatibilizing effect in poly(2, 6-dimethyl-1, 4-phenylene oxide) (PPO)/poly(styrene-co-acrylonitrile) (SAN, 25wt% acrylonitrile) blend was studied. PS block and PCL block in the block copolymer had shown miscibility with PPO and SAN respectively. The dissolution of SAN into PPO domain was promoted by the addition of the PS-PCL block copolymer.

• Polymer(Korea)
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• v.33 no.2
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• pp.137-143
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• 2009

We prepared norfloxacin (NFX)-incorporated polymeric micelle using poly ($\varepsilon$-caprolactone)/poly(ethylene glycol) (PCL/PEG, CE) diblock copolymers. Particle size was from 60 to 200 nm according to the PCL block length. Their critical association concentration (CAC) was decreased according to the increase of PCL block length. $^1H$-NMR study showed core-shell type micelle structures of CE diblock copolymers in the aqueous environment. Drug release from polymeric micelle was continued over 2 days. Duration of drug release was varied according to the PCL block length and drug contents. At antimicrobial activity test, polymeric micelle showed almost similar cytotoxicity compared to NFX itself.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.374-375
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• 2003

최근 나노섬유기술의 중요성이 증가함에 따라 나노섬유를 제조할 수 있는 여러 방법들 중에 상용화의 가능성, 적용 고분자의 다양성, 제조 공정의 단순성, 다양한 제품기술 응용성을 고려할 때 전기방사는 가장 기대되는 방법으로 현재, 다양한 분야의 연구들이 활발히 진행되고 있다[1,3]. 본 연구는 전기 방사 방법을 이용하여 다공성의 Poly($\varepsilon$-caprolactone) 필라멘트를 제조하고, 제조한 필라멘트를 수직기를 이용하여 평직 직물을 제조하여 그 응용 가능성을 확인하는 것이다[2]. (중략)

• 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.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.482-486
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• 2005

The biodegradable poly(${\varepsilon}$-caprolactone)(PCL)/poly(ethylene imine)(PEI) microcapsules containing $Al_2O_3$ and fragrant oil were prepared with different PEI contents. The effects of stirring rate and concentration of the surfactant on the diameter and morphologies of microcapsules were investigated by using scanning electron microscope (SEM). Thermal behaviors were studied by using a differential scanning calorimetry(DSC), and the release behaviors of fragrant oil from microcapsule were characterized by UV/vis. spectrophotometer. As a result, the average particle size of the microcapsules decreased with increasing the stirring rate or concentration of the surfactant. The surface morphologies of the microcapsules were changed from smooth surfaces to skin-like rough surfaces as increasing the PEI content. These results were mainly due to the increased hydrophilic groups at the microcapsule surfaces, resulting in increasing the release rate of fragrant oil in the microcapsules studied.