• Polymer(Korea)
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• v.24 no.3
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• pp.306-313
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• 2000

Polycaprolactone (PCL) macromer containing terminal methacrylate group was synthesized by ring-opening polymerization. The number average molecular weight of PCL macromer was 11600 g/mole and polydispersity index was 1.09. The synthesized PCL macromer was copolymerized with styrene by stable free radical polymerization using 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), benzoyl peroxide, and well-defined poly(styrene-g-caprolactone)s were synthesized. The synthesized copolymers was characterized by $^1$H-NMR and gel permeation chromatography equipped with multiangle laser light scattering detector. Thermal properties of graft copolymers were investigated by DSC.

• Polymer(Korea)
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• v.24 no.2
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• pp.141-148
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• 2000

Polycaprolactone (PCL) was blended with corn starch to produce biodegradable compost films and the biodegradability and mechanical properties were investigated. As the compatibilizer for the immiscible PCL/starch blend, 2-hydroxyethylmethacrylate (HEMA)-PCL macromer was grafted onto starch by initially grafting HEMA to starch and then grafting of PCL onto HEMA via ring opening polymerization of $\varepsilon$-caprolactone. When biodegradability of the PCL grafted starch-g-DEMA copolymers was compared with that of starch by the modified Sturm test, graft copolymers degraded at much slower rates due to the presence of the non-degradable HEMA. With the addition of the graft copolymer up to 5 wt% to the blend, the elongation-at-break of the starch/PCL blend increased substantially, while the tensile strength and modulus did not change much. SEM observation of the blend containing 2 wt% copolymer clearly indicated that the interfacial adhesion between the starch and PCL was strengthened by the copolymer.

• Journal of the Korean Arthroscopy Society
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• v.2 no.1
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• pp.1-3
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• 1998

The PCL reconstruction in chronic isolate PCL reconstruction was still controversy. 1) In isolate PCL deficient knee, functionally not so bad as like ACL deficient knee. 2) The result of the PCL reconstruction was not as good as ACL reconstruction. Therefore, isolate PCL injuries has been treated as nonoperatively. Hey Grovere, who was the first to attempt an intra-articular reconstruction of the PCL, utilized the semi-tendinous tendon other static procedures have been described in only a few cases with very limited follow-up. Dynamic procedures utilizing the medial head of the gastrocnemius has been reported by Hugston and Degenhardt, Kennedy and Grainger, and Insall and Hood. These procedures did not improve static stability. Dr Clancy, who was introduce the use of BPTB for the PCL reconstruction transtibial and femoral tunnel. From 1995, untill early 1990 PCL reconstruction was done as tend as placement of the isometric point. Physiometic placement of Anatomical placement of the femoral tunnel in PCL reconstruction were introduced in 1995. Tibial Inlay Technique was reported by Dr Berg in 1995. The main advantage of the tibial Inlay Technique was to avoid fraying of the graft at the posterior tibial tunnel orifice. In complete PCL ruptured and severely posterior unstable knee, dual femoral tunnel technique will be to get better result than one bundle technique. To achieve restoration of normal posterior laxity, it is critical to address the posterior as well as the posterolateral structures. Futher research is necessary to evaluate new surgical approches such as double-bundle reconstructions and tibial inlay techniques as well as improved techniques for capsular and collateral ligament injuries.

• Korean Journal of Materials Research
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• v.17 no.11
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• pp.622-627
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• 2007

Porous poly(e-caprolactone) (PCL) scaffolds were fabricated by salt leaching method. The PCL scaffolds were treated with aqueous NaOH for 0h, 2h, 4h, 8h, and 12h at $40^{\circ}C$. The NaOH-treated PCL scaffolds were dipped in $CaCl_2$ and $K_2HPO_4{\cdot}_3H_2O$ solution alternately three times to induce apatite nuclei onto the surface of the scaffolds. The NaOH-treated PCL scaffolds were immersed into SBF solution for 1day to grow the apatite. The apatite formation were investigated as a fuction of NaOH treatment time. The hydrophilicty and surface area of the PCL scaffolds were increased with NaOH-treatment time. The NaOH-treated PCL scaffolds were successfully formed a dense and uniform bone-like apatite layer after immersion for 1 day in SBF solution.

• 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.

• Macromolecular Research
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• v.15 no.1
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• pp.39-43
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• 2007

The amphiphilic block copolymer (PEtOz-PCL) of poly(2-ethyl-2-oxazoline) (PEtOz) and poly(${\varepsilon}$-caprolactone) (PCL) formed spherical micellar structures with an average diameter of 26 nm in aqueous phase. Au and Pd nanoparticles with an average diameter of $2{\sim}3nm$ were prepared by using the PEtOz-PCL micelle consisting of a PEtOz shell and PCL core. The Au nanoparticles of PEtOz-PCL micelles in aqueous phase could be transferred into organic phase by using n-dodecanethiol. The use of the Pd-NP/PEtOz-PCL micelle as a nanoreactor for Suzuki cross-coupling reaction was investigated.

• Journal of the Korean Geotechnical Society
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• v.17 no.5
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• pp.197-207
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• 2001

1980년대 이래 국내 터널의 시공법은 원지반의 강성을 활용한 NATM이 주를 이루고 있다. 그러나 NATM은 터널내부에 설치되는 내부라이닝의 여러 가지 문제점을 내포하고 있기 때문에 노르웨이에서는 조립식 터널 라이닝(Pre-Cast Concrete Lining, PCL)을 개발하여 현장타설 콘크리트 라이닝의 문제점을 해결하고자 하였다. 그러나 노르웨이와 같은 북유럽지역에서는 지진이 거의 발생되지 않고 있기 때문에 PCL공법 개발당시에 지진에 대한 영향을 고려하지 못하였다. 따라서 PCL공법을 국내에 도입하기 위해서는 먼저 지진에 대한 영향을 분석하여야 할 것으로 판단되므로 본 연구에서는 PCL공법 적용시 지진에 대한 안정성 평가 및 합리적 내진해석을 위한 연구를 수행하고자 하였다. PCL의 내진성능을 판단하기 위하여 먼저 국내에서 주로 많이 사용되고 있는 해석기법인 유사정적해석법과 응답스펙트럼해석법을 이용하여 분석하였으며 지반과 구조물의 상호작용에 대한 영향을 분석하기 위해 시간이력해석을 수행하여 터널심도별 PCL의 내진성능을 분석하였다. 이와 같은 방법으로 PCL의 내진해석을 수행한 결과, 부재에 발생된 응력이 허용응력 이내에서 발생되어 PCL의 내진성능을 확보된 것으로 판단된다. 또한 시간이력해석에 의한 지반-구조물 해석을 수행한 결과에 의하면 PCL의 내진성능을 확보하기 위한 터널의 최소 토피고가 터널직경에 2배 이상인 것으로 확인되었다. 또한 단순 구조물의 내진해석만으로는 PCL의 내진성능을 과소평가할 우려가 있는 것으로 나타났다.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.341-346
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• 2015

In this study, poly ${\varepsilon}$-caprolactone(PCL) microcapsules containing lemongrass oil was prepared by the solvent evaporation method. Effects of concentrations of PCL and poly vinyl alcohol (PVA) as well as stirring speeds when preparing microcapsules were investigated. Specific peaks of lemongrass oil in PCL microcapsules at 1600 and $2900cm^{-1}$ were observed by FT-IR. The particle size and shape of microcapsules were also measured by polarizing microscope and optical microscopy. The average particle size of microcapsules decreased with increasing the stirring rate. At the stirring speed of 1500 rpm, and 1 wt% of each PCL and PVA concentrations, the smallest particles were formed. Collection efficiencies of lemongrass oil of 77.5% and 69.5% were obtained when 1.5 wt% of PCL and 2 wt% of PVA were used, respectively. In addition, the release behavior and antioxidant activity of lemongrass oil from PCL microcapsules were examined using UV-Vis spectrophotometry. When 0.5 wt% PCL and 2.0 wt% PVA were used with the slow stirring rate, microcapsules showed a fast release rate. The characteristics of antioxidant activity exhibited similar to that of the release behavior.

• Polymer(Korea)
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• v.24 no.1
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• pp.48-57
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• 2000

Polycaprolactone (PCL) and thermoplastic starch (TPS) blends were prepared. Mechanical properties, thermal property, water absorption, biodegradability by composting and surface morphology of PCL/TPS blends were investigated. The compositions of PCL/TPS blends were 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80, and 10/90. Strength and elongation at break decreased as the content of TPS increased, while modulus increased. DSC thermogram of TPS showed two glass transition temperatures (T$_{g}$ ) at 23$^{\circ}C$ and 126$^{\circ}C$. And TPS proved to be an amorphous polymer because there was no endothermic peak due to the melting of starch crystal. The unchanged melting temperatures and T$_{g}$ 's of PCL/TPS blends revealed that PCL and TPS were not miscible. All of the blends were found to be mechanically compatible but phase separated in each other. After 45 days composting, the biodegradability of PCL was 44% and that of PCL/TPS blends increased as the contents of TPS increased.

• Analytical Science and Technology
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• v.27 no.5
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• pp.228-233
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• 2014

Electrospun polymeric nanofibers have been extensively studied for biomedical materials because of their unique structures and relatively easy fabrication with biocompatible polymers. The amount of surface exposed amine groups increases as the blend ratio of block copolymer increases. Cell attachments on the nanofibers change according to the ratio of the block copolymer ((Poly(e-caprolactone, PCL), Poly(e-caprolactone)-Poly (ethylen glycol-$NH_2$)) in the blend. We assume that the PEG and amine moiety plays a significant role in biocompatibility of nanofiber surfaces. Collagen was used as a grafting material on the composite nanofibers to enhance the cell adhesion because the collagen is a major constituent of connective tissue.