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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
The Polymer Society of Korea
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Volume & Issues
Volume 30, Issue 6 - Nov 2006
Volume 30, Issue 5 - Sep 2006
Volume 30, Issue 4 - Jul 2006
Volume 30, Issue 3 - May 2006
Volume 30, Issue 2 - Mar 2006
Volume 30, Issue 1 - Jan 2006
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The Synthesis of Artery Wall Targeted Gene Carrier Using Low Molecular Water-Soluble Chitosan
Choi Chang-Yong ; Jang Mi-Kyeong ; Nah Jae-Woon ;
Polymer Korea, volume 30, issue 4, 2006, Pages 279~285
Non-viral gene carriers continue to attract a great deal of interest due to advantageous safety profile. Among the non-viral gene carriers, cationic liposomes or synthetic gene carriers are efficient DNA carriers in vitro. but their in vivo applications are greatly hampered because of low biocompatibility. On the other hand, chitosan, a natural cationic polysaccharide, is a candidate non-viral vector for gene delivery because of its low cytotoxicity and high positive charges. In this work, targeted gene carrier was synthesized to target artery wall cells using low molecular water-soluble chitosan (LMWSC). The molecular weight
and degree of de acetylation (DDA) of LMWSC were measured by relative viscometer and Kina titration. respectively. The structure of LMWSC was analyzed by measuring FTIR,
. AWBP-PEG-g-LMWSC was synthesized by conjugation of the artery wall binding peptide (AWBP), a specific targeting peptide, to the end of pegylated LMWSC as a gene carrier to target artery wall cells. The synthesized AWBP-PEG-g-LMWSC were analyzed by measuring FTIR,
, zeta -potentiometer, and atomic force microscopy (AFM).
Preparation and Super-Water-Absorbency of Poly(sodium acrylate-co-acrylamide-co-2-hydroxyethyl acrylate)
Zhang Yuhong ; Deng Min ; He Peixin ;
Polymer Korea, volume 30, issue 4, 2006, Pages 286~292
Super water-absorbent resins were prepared by inverse suspension copolymerization of sodium acrylate, acrylamide and 2-hydroxyethyl acrylate using N, N'-methylene-bis-acrylamide as cross-linker. For the suspension copolymerization, monohexadecyl phosphate was employed as the dispersing agent, cyclohexane as the dispersing medium and potassium persulfate as the initiator. The dependence of water-absorption capacity on the amount of crosslinking agent, oil/water ratio, degree of neutralization and the composition of the copolymer were systematically investigated. Furthermore, the swelling kinetics of the super water-absorbent copolymer was carried out. The absorption of the resins is more than 1800 g/g for deionized water and 100 g/g for 0.9% NaCl solution, respectively. The copolymers showed an increased salt resistance and enhanced water retention of soil.
Adsorption Properties of Oxidized NO by Plasma Using Hybrid Anion-Exchange Fibers
Cho In-Hee ; Kang Kyung-Seok ; Hwang Taek-Sung ;
Polymer Korea, volume 30, issue 4, 2006, Pages 291~297
In this study, adsorption properties of oxidized NO by plasma using aminated polyolefin-g-GMA hybrid anion exchange fibers were investigated. The maximum conversion of
by plasma was 49% at the conditions of 200 ppm NO, 10%
and 30 L/min of flow rate. The adsorption content for N02 of hybrid anion exchange fibers increased with increasing the swelling ratio and the highest value was 1.5 g
IEF. The adsorption of
by hybrid anion exchange fibers were very fast until 10 min and reached its maximum value of 80% at 120 min. Ion exchange capacity of hybrid anion exchange fibers increased with increasing the swelling ratio and it showed the highest 0.6 mmol/g IEF values at L/D=5. The adsorption isotherm model for hybrid anion exchange fibers were closer to Freundlich than Langmuir adsorption isotherm model. It was shown that adsorption of the multi-molecular layer was dominant.
Blend Films of Poly(acrylic acid-co-maleic acid) with Poly(vinyl alcohol) (I) : Thermo-mechanical Properties and Gas Permeability
Ham Shin-Kyun ; Jung Min-Hye ; Chang Jin-Hae ;
Polymer Korea, volume 30, issue 4, 2006, Pages 298~304
Blends of poly (acrylic acid-co-maleic acid)(PAM) with poly (vinyl alcohol)(PVA) were obtained by solution blending. The blends were solvent-on to a film to examine thermo-mechanical properties and gas permeability. The transition temperatures
of the blends remained constant regardless of PAM contents. However, the values of enthalpy changes corresponding to melting transition
and initial degradation temperature
were decreased with increasing PAM content. The values of ultimate strength and initial modulus gave the maximum value at the 12 wt% PAM then decreased with further increase of PAM content up to 15 wt%. To measure the gas permeability of the PVA/PAM blend films, the PVA blend solutions were coated onto both biaxially oriented propylene (BOPP) and poly (ethylene terephthalate)(PET) films. The oxygen transmission rate
permeability values mono- tonically decreased with increasing PAM content. However, moisture vapor transmission rate was not affected by PAM content.
Synthesis of Hybrid Cation Exchange Fibers by E-Beam Preirradiation and Their Adsorption Properties for Metal Ions
Baek Ki-Wan ; Nho Young-Chang ; Hwang Taek-Sung ;
Polymer Korea, volume 30, issue 4, 2006, Pages 305~310
The hybrid cation exchange fibers using graft copolymer of styrene onto PE/PP with PET trunk polymers were synthesized by electron beam preirradiation. The degree of grafting showed 123% value at 80% concentration of styrene. And also, amount of sulfonyl group in the ion exchanger was showed 3.3 mmol/g at 70% concentration of styrene and their values were constant after 70%. The tensile strength for fibers was lower than trunk fibers, and their value of ion exchange fibers were also below than copolymer. It was
value. The breakthrough time for Ca and Mg ions of hybrid cation exchange fibers were increased with the increase in the pH and temperature. The breakthrough of Mg was slower the mixture than single Mg solution. Adsorption rate constant for Ca, Mg ions and maximum ion exchange capacity were 0.012, 0.011 L/mg.h and 47.06, 42.83 mg/g, and also, activation energies were 2169 and 1534 J/mol, respectively.
Preparation of Poly-DCPD/Silicate Nanocomposites and Their Physical and Mechanical Properties
Hong Chae-Hwan ; Song Suk-Woo ; Nam Byeong-Uk ; Cha Bong-Jun ; Kim Baek-Jin ;
Polymer Korea, volume 30, issue 4, 2006, Pages 311~317
Poly-DCPD and poly-DCPD/silicates hybrids were prepared by in-situ ROMP poly-merization using
catalyst. Good dispersion of silicates in DCPD medium can be accomplished by sonication method. Compared with nanocomposites prepared using
, the nanocomposites with CL 15A showed well dispersed silicate's morphology. superior thermal and mechanical properties. Additionally, well dispersed silicates in DCPD matrix enhanced the gas barrier property of the nanocomposites.
Preparation of Polypropylene/Clay Nanocomposites Using Aminosilane Treated Clay
Hong Chae-Hwan ; Bae Jin-Woo ; Lee Yong-Bum ; Lee Choon-Soo ; Jho Jae-Young ; Nam Byeong-Uk ;
Polymer Korea, volume 30, issue 4, 2006, Pages 318~325
Polypropylene-clay nanocomposites were studied by the modification of clay with amino silanes to introduce covalent bonds in nanocomposites, and prepared by melt-compounding with polypropylene, clay modified with amino silanes and maleic anhydride grafted polypropylene. The . .structure and surface properties of modified clay were determined by x-ray diffraction, infrared spectrum, and solid-state
nuclear magnetic resonance spectrum. The modification of clay with aminosilanes led to the increase of the silicate interlayers to about
, the weakening effects of hydroxy group at
and the signal of amine groups at -69 ppm proved that the modification had taken place.
A Study on the Process in MMA/IPMI/Styrene Terpolymerization
Park Jong-Kyoung ; Yoon Sung-Cheol ; Jin Jung-Il ; Lee Chang-Jin ;
Polymer Korea, volume 30, issue 4, 2006, Pages 326~331
MMA(methyl methacrylate)/IPMI(N-isopropyl maleimide) copolymers are one of the well known heat resistant materials for POF(plastic optical fiber). However, because of the large difference in the reactivity ratio between MMA and IPMI
, the compositional drift occurs during the polymerization process which causes the deterioration of the physical properties of these copolymers. In this paper, we report that the compositional drift of the copolymer could be reduced by the addition of styrene (St) which increased the reactivity of IPMI in the MMA/IPMI copolymerization system and conversion was also increased by 1.5 or 2 times. The MMA/IPMI/St terpolymer had higher refractive index than the MMA/IPMI copolymer which depended on the contents of sytrene.
Mechanical Properties of Monodisperse Polymer Particles and Electroless Ni Plated Monodisperse Polymer Particles
Kim Dong-Ok ; Jin Jeong-Hee ; Shon Won-IL ; Oh Seok-Heon ;
Polymer Korea, volume 30, issue 4, 2006, Pages 332~337
Monodisperse polymer particles were prepared via one-step seeded polymerization using PMMA seed particles and HDDA (or EGDMA) as crosslinking monomer. For the study, the effects of 1) the ratio of the absorbed monomer or monomer mixture to the seed polymer particles (swelling ratio), 2) the ratio of EGDMA in absorbed monomer mixture, 3) the dosage of initiator, and 4) electro less Ni plating on the variation of mechanical properties of monodisperse polymer particles, such as recovery rate, K-values, breaking strength and breaking displacement, were investigated by using MCT (micro compression test). It was observed that monomer swelling ratio influenced only breaking strength, but EGDMA ratio in monomer mixture, dosage of initiator and electroless Ni plating affected both K-values and breaking strength.
Thermotropic Liquid Crystalline Properties of (8-Cholesteryloxycarbonyl)heptanoated Polysaccharides
Jeong Seung-Yong ; Ma Yung-Dae ;
Polymer Korea, volume 30, issue 4, 2006, Pages 338~349
Fully or nearly fully(8-cholesteryloxycarbonyl)heptanoated polysaccharide derivatives were synthesized by reacting cellulose, amylose, chitosan, chitin, alginic acid, pullulan or amylopectin with (8-cholesteryloxycarbonyl)heptanoyl chloride (CH8C), and their thermotropic liquid crystalline behaviors were investigated. Like in the case of CH8C, all the polysaccharide derivatives formed monotropic cholesteric phases with left-handed helicoidal structures whose optical pitches
decrease with increasing temperature. Amylopectin derivative also formed a monotropic cholesteric phase with lefthanded helicoidal structures but, in contrast with the other derivatives, did not display reflection colors over the full cholesteric range, suggesting that the helicoidal twisting power of the cholesteryl group highly depends on the branched structure in amylopectin. The thermal stability and degree of order in the mesophase, the magnitude of
at the same temperature, and the temperature dependence of the
observed for polysaccharide derivatives were entirely different from those reported for the polymers in which the cholesteryl groups are attached to flexible or semiflexible backbones through flexible spacers. The results were discussed in terms of the difference in the chemical structures of the main and side chains and flexibility of the main chain.
Relationship between Weather-Resistance and Mixing Ratio of Mill-Base and Let-Down Silicone/Acrylic Resins
Jo Hye-Jin ; Shim Il-Woo ; Hahm Hyun-Sik ; Park Hong-Soo ;
Polymer Korea, volume 30, issue 4, 2006, Pages 350~356
In order to investigate the effect of the composition of weather-resistant coatings on physical properties, three different weather-resistant coatings were prepared by varying the ratio of a mill-base silicone/acrylic resin and let-down silicone/acrylic resin in weight ratios of 2 : 8, 3 : 7, and 4 : 6. The physical properties and weather-resistance of the prepared coatings were tested. It was found that the thermal stability, salt spray exposure, and weather-resistance were improved with increasing the amount of silicone. The optimum mixing ratio of mill-base silicone/acrylic resin to the let-down silicone/acrylic resin was 2 : 8. The coating containing silicone component of 30 wt% was found to be suitable as high weather-resistant coatings.
Ring Opening and Polymerization of Alpha-Lipoic Acid
Park Chul-Ho ; Kim Ae-Ran ; Yun Hye-Lee ; Lee Jong-Hwi ;
Polymer Korea, volume 30, issue 4, 2006, Pages 357~361
Alpha-lipoic acid (ALA) synthesized in the body has virtues such as anti-oxidation, blood sugar regulation, appetite suppression, and anti-obesity, etc. ALA, which is also used as a drug, has a five-membered ring including disulfide and so easily losses bioavailability due to ring opening and subsequent polymerization by heat or ultraviolet. This report studies various conditions for ring opening polymerization. The ring opening starts above the melting point of ALA, but there was no temperature dependence above it. At
, the degree of ring opening was proportional to reaction time and inversely proportional concentration. The degree of ring opening in acetic acid with UV for 1 hour reached the maximum conversion (70%). Most cleaved ALA changed into disulfide polymers, and the molecular weight of the polymers increased as the amount of ring opening increased.
Molecular Orientation of Evaporated Pentacene Film on Polyimide Alignment Layer
Kim Beom-Kyung ; Kim Do-Hoi ; Chung Jae-Sun ; Kim Young-Ju ; Seo In-Seon ; Kwon Soon-Ki ; Song Ki-Gook ;
Polymer Korea, volume 30, issue 4, 2006, Pages 362~366
It was found by polarized FTIR spectroscopic studies that pentacene molecules are arranged with their molecular axes perpendicular to the substrate surface when pentacene films are deposited on a polyimide alignment layer. The ring plane in a pentacene molecule is arranged parallel to the rubbing direction of the polyimide alignment film while no specific arrangement of vertically deposited pentacene molecules was found for the film without rubbing. The pentacene band at
which has a transition dipole moment parallel to the ring plane is much stronger in a polarized IR spectrum of parallel to the rubbing direction, whereas the band at
whose transition dipole align normal to the ring plane shows much stronger intensity in a spectrum of perpendicular to the rubbing direction. These findings indicate that orientation of polyimide chains affects the arrangement of pentacene molecules when they are deposited on a polyimide alignment film.