• Title, Summary, Keyword: Poly(l-lactide)

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Interfacial Evaluation of Plasma-Treated Biodegradable Poly(p-dioxanone) Fiber/Poly(L-lactide) Composites Using Micromechanical Technique and Dynamic Contact Angle Measurement (Micromechanical 시험법과 동적접촉각 측정을 이용한 플라즈마 처리된 생분해성 Poly(p-dioxanone) 섬유강화 Poly(L-lactide) 복합재료의 계면물성 평가)

  • Park, Joung-Man;Kim, Dae-Sik;Kim, Sung-Ryong
    • Journal of Adhesion and Interface
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    • v.4 no.1
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    • pp.18-27
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    • 2003
  • Interfacial properties and microfailure degradation mechanisms of the oxygen-plasma treated biodegradable poly(p-dioxanone) (PPDO) fiber/poly(L-lactide) (PLLA)composites were investigated for the orthopedic applications as implant materials using micromechanical technique and surface wettability measurement. PPDO fiber reinforced PLLA composite can provide good mechanical performance for long hydrolysis time. The degree of degradation for PPDO fiber and PLLA matrix was measured by thermal analysis and optical observation. IFSS and work of adhesion, $W_a$ between PPDO fiber and PLLA matrix showed the maximum at the plasma treatment time, at 60 seconds. Work of adhesion was lineally proportional to the IFSS. PPDO fiber showed ductile microfailure modes at We initial state, whereas brittle microfailure modes appeared with elapsing hydrolysis time. Interfacial properties and microfailure degradation mechanisms can be important factors to control bioabsorbable composites performance because IFSS changes with hydrolytic degradation.

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The Synthesis of Cellulose-graft-poly (L-lactide) by Ring-opening Polymerization and the Study of Its Degradability

  • Dai, Lin;Xiao, Shu;Shen, Yue;Qinshu, Baichuan;He, Jing
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.4122-4126
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    • 2012
  • Cellulose-graft-poly (L-lactide) (cellulose-g-PLLA) was successfully prepared via ring-opening polymerization (ROP) by using 4-dimethylaminopyridine (DMAP) as an organic catalyst in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). The structure and morphology of the polymer was characterized by nuclear magnetic resonance (NMR) and transmission electron microscope (TEM). From wide-angle X-ray powder diffraction (WAXD) and degradation test (by acid, alkaline, PBS and enzyme solution), changes in the crystalline structure as a result of degradation was also investigated. The results indicated that materials which have low degree of crystallinity showing higher degradability, however, in acid liquor, enzyme solution, alkaline liquor and PBS system, the degradation rate of the polymer decreased by the above sequence. Moreover, with the further increase of graft degree of this material, its degradation degree decreased.

Preparation and Physical Properties of Biodegradible Poly(L-lactide )/silica Composites (생분해성 폴리락타이드/실리카 복합체 제조 및 특성)

  • Lee, Byung-Ick;Kim, Sung-Hun;Lee, Moo-Sung
    • Textile Science and Engineering
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    • v.45 no.5
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    • pp.269-275
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    • 2008
  • The composites of poly(l-lactide) (PLLA) and silica were prepared using a Haake melt mixer. In order to improve the interfacial adhesion between the two components silica was modified using three different silane coupling agents with different functional moieties. For the case that silica is treated with GPTS or MPTS, the molecular weight of PLLA are significantly reduced. This results in the lowering of the glass transition temperature ($T_g$) and melt viscosity of the composites. However, when the APTS-treated silica with amine functionality is added to PLLA, the storage modulus and melt viscosity of the composites are somewhat increased compared to neat PLLA. The rate of melt crystallization of PLLA is also increased as a result of surface treatment of silica.

Compatibilization of Immiscible Poly(l-lactide) and Low Density Polyethylene Blends

  • Kim Young Fil;Choi Chang Nam;Kim Young Dae;Lee Ki Young;Lee Moo Sung
    • Fibers and Polymers
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    • v.5 no.4
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    • pp.270-274
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    • 2004
  • Blends of poly(l-lactide) (PLA) and low density polyethylene (LDPE) were prepared by melt mixing in order to improve the brittleness of PLA. A reactive compatibilizer with glycidyl methacrylate (GMA), PE-GMA, was required as a compatibilizer due to the immiscibility between PLA and LDPE. It contributes to reduce the domain size of dispersed phase and enhance the tensile properties of PLA/LDPE blends, especially for PLA matrix blends. A reaction product between PLA and PE-GMA, which was formed during melt-mixing and considered to act as a reactive compatibilizer, was characterized using $ ^1H-NMR$ spectroscopy.

Preparation of Gemcitabine-Loaded Methoxy Poly(ethylene glycol)-b-Poly(L-lactide) Microparticles Using W/O/W Double Emulsion (W/O/W 다중유화법을 이용한 젬시타빈 함유 Methoxy Poly(ethylene glycol)-b-Poly(L-lactide) 미립자 제조)

  • Ryu, Jong-Hoon;Jung, In-Il;Lee, Ji-Eun;Lim, Gio-Bin
    • KSBB Journal
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    • v.26 no.4
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    • pp.333-340
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    • 2011
  • In this study, gemcitabine-loaded methoxy poly(ethylene glycol)-b-poly(L-lactide) (MPEG-PLLA) microparticles with different PEG block lengths were prepared by a W/O/W double emulsion technique. The present study focuses on the investigation of the influence of various preparative parameters such as the ratio of internal water phase and oil phase, polymer concentration, solvent composition of organic phase and salt concentration of external water phase on the morphology and encapsulation efficiency of the microparticles. The microparticles fabricated at high volume ratios of internal water phase to oil phase and at high polymer concentrations showed a relatively high encapsulation efficiency and low porosity. When a dichloromethane/ethyl acetate mixture was used as solvent, both the encapsulation efficiency and drug loading of the microparticles decreased as the level of ethyl acetate increased. The addition of a salt (NaCl) to the external water phase significantly improved the encapsulation efficiency up to 40%, and the microparticles became more spherical with their size and porosity decreased.

Synthesis and Characterization of Poly(L-lactide)(L-PLA), Poly(D-lactide)(D-PLA) and Stereocomplex-poly(lactide)(PLA) (L-폴리락타이드, D-폴리락타이드의 활성과 입체복합체 폴리락타이드의 제조 및 특성연구)

  • Kim, Ji-Hyun;JeGal, Jong-Geon;Song, Bong-Keun;Shin, Chae-Ho
    • Polymer(Korea)
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    • v.35 no.1
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    • pp.52-59
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    • 2011
  • L-PLA or D-PLA was synthesized in bulk at $140^{\circ}C$ by ring opening polymerization(ROP) of L-lactide or D-lactide as a monomer using tin(II) octoate and lauryl alcohol as a catalyst and an initiator with changing the amounts of catalyst(0.25~1.0 wt%) and initiator(0.l~0.5 wt%). And stereocomplex-PLA was prepared by L-PLA/D-PLA having a wide range of molecular weight(30000~90000 g/mol) and L-PLA/D-PLA blends having different mixing ratio ($X_D$). The melting temperature. thermal degradation temperature and thermal stability of stereocomplex-PLA were higher than those of homopolymers(L-PLA, D-PLA). We supposed that these improvements arose from a strong interaction between L-PLA and D-PLA. The improved mechanical properties and changes in morphology of LPLA/D-PLA blends were compared to those of homopolymers(L-PLA, D-PLA).

Core-shell Poly(D,L-lactide-co-glycolide )/Poly(ethyl 2-cyanoacrylate) Microparticles with Doxorubicin to Reduce Initial Burst Release

  • Lee, Sang-Hyuk;Baek, Hyon-Ho;Kim, Jung-Hyun;Choi, Sung--Wook
    • Macromolecular Research
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    • v.17 no.12
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    • pp.1010-1014
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    • 2009
  • Monodispersed microparticles with a poly(D,L-lactide-co-glycolide) (PLGA) core and a poly(ethyl 2-cyanoacrylate) (PE2CA) shell were prepared by Shirasu porous glass (SPG) membrane emulsification to reduce the initial burst release of doxorubicin (DOX). Solution mixtures with different weight ratios of PLGA polymer and E2CA monomer were permeated under pressure through an SPG membrane with $1.9\;{\mu}m$ pore size into a continuous water phase with sodium lauryl sulfate as a surfactant. Core-shell structured microparticles were formed by the mechanism of anionic interfacial polymerization of E2CA and precipitation of both polymers. The average diameter of the resulting microparticles with various PLGA:E2CA ratios ranged from 1.42 to $2.73\;{\mu}m$. The morphology and core-shell structure of the microparticles were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The DOX release profiles revealed that the microparticles with an equivalent PLGA:E2CA weight ratio of 1:1 exhibited the optimal condition to reduce the initial burst of DOX. The initial release rate of DOX was dependent on the PLGA:E2CA ratio, and was minimized at a 1:1 ratio.

Synthesis of Poly(DL-lactide-co-glycolide) Copolymers and Its Application (I). Release Characteristics of Clonazepam Using Poly(DL-lactide-co-glycolide) (80:20) Copolymers (Poly(DL-lactide-co-glycolide) 공중합체의 합성과 그 응용 (I). Poly(DL-lactide-co-glycolide)(80:20) 공중합체를 이용한 Clonazepam의 방출특성)

  • Nah, Jae Woon;Lee, Dong Byung;Cho, Chong Su;Jeong, Young Il;Kim, Sung Ho;Kim, Sung Hyun
    • Journal of the Korean Chemical Society
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    • v.42 no.1
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    • pp.92-98
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    • 1998
  • Poly(DL-lactide-co-glycolide) (80:20) was synthesized from DL-lactide and glycolide, and the copolymers was made to micelles containing clonazepam for drug delivery system. The release experiments of the drug from micelles were operated at pH 7.4 phosphate buffer solution $37.0{\pm}0.05^{\circ}C$. The linearly-releasing time ranges of the drug from micelles prepared with the copolymer/drug weight ratio of 20:40, 20:20, and 40:20 (mg) were 50, 41, and 29 days, respectively. So the linearly-releasing time of drug showed the order of micelles 20/40 > micelles 20/20 > micelles 40/20. In short, the formulation allows polymeric micelles to suppress the burst effect of the drug release mechanism, which led to the controlled release pattern and the possibility of drug delivery system for veinous injection.

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Effect of Composition and Synthetic Route on the Microstructure of Biodegradable Diblock Copolymer, Poly($\varepsilon$-caprolactone-co-L-lactide)-b-Poly(ethylene glycol)

  • Min, Youn-Jin;Lee, Seong-Nam;Park, Jung-Ki;Cho, Kuk-Young;Sung, Shi-Joon
    • Macromolecular Research
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    • v.16 no.3
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    • pp.231-237
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    • 2008
  • Biodegradable poly($\varepsilon$-caprolactone-co-L-lactide)-b-poly(ethylene glycol) (PCLA-b-PEG) copolymers were synthesized via solution polymerization by varying the feed composition of $\varepsilon$-caprolactone ($\varepsilon$-CL) and L-lactide (LLA) ($\varepsilon$-CL: LLA= 10:0, 7:3, 5:5, 3:7, 0: 10). The feed ratio based on weight is in accordance with the copolymer composition except for the case of $\varepsilon$-CL: LLA=3:7 (C3L7), which was verified by $^1H$-NMR. Two different approaches were used for the exceptional case, which is an extension of the reaction time or the sequential introduction of the monomer. A copolymer composition of $\varepsilon$-CL: LLA=3:7 could be obtained in either case. The chemical microstructure of PCLA-b-PEG was determined using the $^{13}C$-NMR spectra and the effect of the sequential structure on the thermal properties and crystallinity were examined. Despite the same composition ratio of the copolymer, the microstructure can differ according to the reaction conditions.

Application of Drug Release Carrier with Block Copoly(esterether) Comprising Poly(L-lactide) and Poly(oxyethylene) (Poly(L-lactide)(PLLA)/Polyoxyethylene(POE) 블록공중합체의 약불방출담체에 관한응용)

  • Lee, Chan-Woo;Ihm, Dae-Woo;Jun, Kun
    • Textile Science and Engineering
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    • v.37 no.9
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    • pp.519-523
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    • 2000
  • An A-B-A block copoly(ester-ether) comprising poly(L-lactic acid)(PLLA, A) and poly (oxyethylene)(POE, B) was prepared by copolymerization. The release rate of the model drugs form PLLA/POE particles was studied by varying the hydrophilicity of the model drugs as well as that of the copolymers. It was observed that the rate of controlled release from the copolymer microspheres is not dependent on the degradation of the polymer, but on the wall permeability which is defined as the product of diffusion coefficient and the solubility coefficient. The release rate was fast as long as the hydrophilicity of the copolymer was high, regardless of the composition of the copolymer. It was also found that the release rate was faster as the monomer composition of the oxyethylene unit becomes higher.

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