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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 35, Issue 6 - Nov 2011
Volume 35, Issue 5 - Sep 2011
Volume 35, Issue 4 - Jul 2011
Volume 35, Issue 3 - May 2011
Volume 35, Issue 2 - Mar 2011
Volume 35, Issue 1 - Jan 2011
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Mechanical Property and Cell Compatibility of Silk/PLGA Hybrid Scaffold; In Vitro Study
Song, Yi-Seul ; Yoo, Han-Na ; Eum, Shin ; Kim, On-You ; Yoo, Suk-Chul ; Kim, Hyung-Eun ; Lee, Dong-Won ; Khang, Gil-Son ;
Polymer Korea, volume 35, issue 3, 2011, Pages 189~195
The design of new bioactive scaffolds offering physiologic environment for tissue formation is an important frontier in biomaterials research. In this study, we performed compressive strength, water-uptake ability, and SEM analysis for physical property assessment of 3-D silk/PLGA scaffold, and investigated the adhesion, proliferation, phenotype maintenance, and inflammatory responses of RAW 264.7 and NIH/3T3 for cell compatibility. Scaffolds were prepared by the solvent casting/salt leaching method and their compressive strength and water-uptake ability were excellent at 20 wt% silk content. Result of cell compatibility assay showed that inflammatory responses distinctly decreased, and initial adhesion and proliferation were maximized at 20 wt% silk content. In conclusion, we suggest that silk/PLGA scaffolds may be useful to tissue engineering applications.
Cure Kinetics and Dynamic Mechanical Properties of an Epoxy/Polyoxypropylene Diamine System
Huang, Guang-Chun ; Lee, Jong-Keun ;
Polymer Korea, volume 35, issue 3, 2011, Pages 196~202
The cure kinetics of a bisphenol A epoxy resin and polyoxypropylene diamine curing agent system are investigated in both dynamic and isothermal conditions by differential scanning calorimetry (DSC). In dynamic experiments, the shift of exothermic peaks obtained at different heating rates is used to obtain activation energy of overall cure reaction based on the methods of Ozawa and Kissinger. Isothermal DSC data at different temperatures are fitted to an autocatalytic Kamal kinetic model. The kinetic model is in a good agreement with the experimental data in the initial stage of cure. A diffusion effect is incorporated to describe the later stage of cure, predicting the cure kinetics over the whole range of curing process. Also, dynamic mechanical analysis is performed to evaluate the storage modulus and average molecular weight between crosslinkages.
Analysis of Mechanical Properties and Stress Crack Behavior of HOPE Geomembranes by Laboratory Installation Damage Test
Khan, Belas Ahmed ; Park, Ju-Hee ; Kim, Sung-Hee ; Chang, Yong-Chai ; Oh, Tae-Hwan ; Lyoo, Won-Seok ; Jeon, Han-Yong ;
Polymer Korea, volume 35, issue 3, 2011, Pages 203~209
Two smooth and textured surfaced HDPE geomembranes (GMs) were cut into dumbbell shape and notched where depth of the notch produced a ligament thickness of 10% to 90% of the nominal thickness with the specimen at 10% interval. A series of laboratory simulation test for installation damage were carried out at different loading cycles on HDPE GMs in accordance with ISO 10722 test method and the effect of number of loading cycle on installation damage was compared. It was found that yield stress and elongation at yield point decreased gradually as the notch depth was increased. Both installation damaged and notched, GMs were used to understand stress crack behavior and this behavior was observed through NCTL test at
at different yield stresses immerging in pH 4 and pH 12 buffer solutions. Over 35% tensile load, GMs became vulnerable to stress cracking. Both damaged and notched GMs showed the same trend. Especially, notched GMs showed less strength than installation damaged GMs at every stress cracking test condition.
Fabrication and Biocompatibility of Rutin-containing PHBV Nanofibrous Scaffolds
Chae, Won-Pyo ; Xing, Zhi-Cai ; Kim, Yong-Jin ; Sang, Hie-Sun ; Huh, Man-Woo ; Kang, Inn-Kyu ;
Polymer Korea, volume 35, issue 3, 2011, Pages 210~215
Rutin (R) exhibits a wide range of biological activities including anticarcinogenic, antiinflammatory and antiviral actions. The purpose of this study is to investigate the effect of rutin concentrations (1 and 3 wt%) on the antibacterial activity of poly(3-hydroxybutylate-co-hydroxyvalerate) (PHBV) scaffolds. Antibacterial activity was evaluated by using Staphylococcus aureus and Klebsiella pneumoniae. Furthermore, the qualitative ongrowth of human KB endothelial cells was done to study in vitro cytotoxicity of the scaffolds. As the results, PHBV scaffolds containing 3 wt% rutin completely inhibited the proliferation of Staphylococcus aureus and Klebsiella pneumoniae. In addition, the PHBV/R scaffolds used in this study did not show any cytotoxicity when evaluated them with KB endothelial cells.
Fabrication of Electrochemical Microbial Biosensor Based on MWNT Supports Prepared by Radiation-Induced Graft Polymerization
Shin, Soo-Ran ; Kwen, Hai-Doo ; Choi, Seong-Ho ;
Polymer Korea, volume 35, issue 3, 2011, Pages 216~222
A multi-walled carbon nanotube (MWNT) support with dual properties, an ionic property via tetra-amine and unpaired electrons via tri-amine, was prepared by radiation-induced graft polymerization of glycidyl methacrylate (GMA) and the subsequent amination of its epoxy group. The electrochemical microbial biosensor (EMB) was then fabricated by immobilization of a microbe (Alkaligenes spp.) onto the dual property-modified electrode, which was prepared with the mixture of the MWNT support and a
solution on a glass carbon (GC) electrode surface by a hand-casting method. The sensing range of the prepared EMB for phenol in a phosphate buffer solution was 0.005~7.0 mM. The total concentration of phenolic compounds in a commercial red wine was also determined using the EMB.
Thermoresponsive Graft Copolymers of Hyaluronic Acid
Choi, So-Young ; Lee, Jong-Hwi ;
Polymer Korea, volume 35, issue 3, 2011, Pages 223~227
Stimuli-responsive polymers have been investigated as the materials playing the critical roles in various applications. Thermoresponsive graft copolymers, poly (N-isopropylacrylamide)-g-hyaluronic acid (PNIPAAm-g-HA) and elastin-like peptide-g-hyaluronic acid (ELP-g-HA), were synthesized by coupling carboxylic polymers (PNIPAAm-COOH or ELP) to biocompatible HA through amide linkages. Thermoresponsive behavior was observed in both the copolymers, and the results of turbidity measurement were consistent with the results of rheological examination. Among the two copolymers, the ELP graft copolymer shows less cooperative LCST transition than the PNIPAAm case. As the content of graft chains of PNIPAAm and ELP increases, viscosity increases, and the increase was larger in PNIPAAm case at a graft content. These results shows us that the introduction of grafts provides thermosensitivity to biocompatible HA, whose characteristics can be engineered.
Vulcanization Efficiency of Non-polar Rubber Compounds by Microwave
Jung, U-Sun ; Lee, Won-Ki ; Lim, Kwon-Tack ;
Polymer Korea, volume 35, issue 3, 2011, Pages 228~231
The rate of vulcanization of nonpolar ethylene-propylene-diene terpolymer(EPDM)/carbon black compounds was investigated by using hot air and microwave as a heating source. The present study parameters such as heating source, sample thickness, and loading of an additive. The compound thickness was the main factor in the hot air vulcanization. It was due to the poor thermal conductivity of EPDM; that is, the thicker thickness, the lower vulcanization rate. For 100% vulcanization, the compound with 3 mm thickness required 7 min at
in the hot air system. However, the vulcanization of EPDM compounds by microwave system was not affected by the thickness while strongly dependent on the amount of a polar additive, carbon black. A compound with 80 phr of carbon black was perfectly vulcanized within 30 sec. These results suggest that the use of microwave as a heating source is an effective method for the vulcanization of compounds including a polar component.
Experimental and Theory for Relaxation Spectrum of Polyacrylonitrile-Poly(vinyl chloride) Copolymers
Kim, Nam-Jeong ;
Polymer Korea, volume 35, issue 3, 2011, Pages 232~237
The relaxation spectra of polyacrylonitrile-poly(vinyl chloride) copolymer filament fibers were obtained by applying the experimental stress relaxation curves to the theoretical equation of relaxation spectrum. The theoretical equation of relaxation spectrum was derived from the Ree-Eyring and Maxwell model. The experimental of stress relaxation was carried out using a tensile tester with a solvent chamber. The determination of relaxation spectra was performed by computer calculation. From the relaxation spectra, the fine structures, viscoelastic properties and hole volumes of solid polymers were studied. It was observed that the relaxation spectra of these samples were directly related to the distribution of molecular weights and self diffusions of flow segments.
Controlling the Location of Thermally Stable Au Nanoparticles with Tailored Surface Property within Block Copolymer Templates
Kim, Se-Yong ; Yoo, Mi-Sang ; Jung, Se-Ra ; Paek, Kwan-Yeul ; Kim, Bum-Joon J. ; Bang, Joona ;
Polymer Korea, volume 35, issue 3, 2011, Pages 238~243
Organic/inorganic hybrid materials have a lot of interest in various areas due to their fascinating properties. To control the location and dispersion of inorganic nanoparticles within polymer matrix. thiol-terminated polymeric ligands have been widely used to tune the surface property of nanoparticles. However, the specific binding between the thiol functional group and metal is unstable with increasing temperature. To archive the thermally-stable Au nanoparticles, we previously synthesized various UV-crosslinkable polymeric ligands, which have different compositions of polar, UV-crosslinkable azide unit comparing to non-polar 스티렌 units. After crosslinking the Au nanoparticles, it was found that the nanoparticles had superb stability at high temperature (above
). In this work, we used thermally-stable Au nanoparticles to control the location within the polymer matrix. By changing the amount of polar azide units in the polymeric ligands, we could precisely control the location of nanoparticles from one domain to the interface of block copolymer templates.
Preparation and Characteristics of Poly(phenylene ether)s in Various Reaction Conditions
Park, Jong-Hyun ; Kim, Nam-Cheol ; Kim, Yong-Tae ; Nam, Sung-Woo ; Kim, Young-Jun ; Kim, Ji-Heung ;
Polymer Korea, volume 35, issue 3, 2011, Pages 244~248
Poly(2,6-dimethyl-1,4-phenylene ether) (PPE) was synthesized by oxidative polymerization using various Cu(I)-amine catalyst system. The effects of catalyst/monomer ratio, different amine ligand, and the content of 2,4,6-trimethylphenol (TMP) additive on the polymer yield and molecular weight were investigated by using gel permeation chromatography. The catalytic activity of various Cu-amine systems on the 2,S-dimethylphenol (DMP) polymerization was monitored and compared each other through oxygen-uptake experiment. In addition, the effect of catalyst removal using aqueous EDTA on the thermal stability of the prepared polymer was elucidated by thermogravimetric analysis.
Effect of Transesterification on the Characteristics of PET/PEN Blend Flexible Substrate
Kim, Jae-Hyun ; Kim, Whan-Ki ; Yum, Ju-Sun ; Kang, Ho-Jong ;
Polymer Korea, volume 35, issue 3, 2011, Pages 249~253
The effect of morphological development in PET/PEN blending on the physical properties of PET/PEN blend film as a flexible substrate was investigated. The two phase morphology was obtained in PET/PEN blends and it caused the improvement of dimensional stability of PET/PEN blend as a flexible substrate. The two phase morphology and crystallinity of PET/PEN blends could be controlled by the transesterification between PET and PEN during the film processing and this macroscopic structural development affected the dimensional stability of PET/PEN blend films. Better dimensional stability was obtained with increasing crystallinity and decreasing the level of transesterification.
Coaxial Nozzle Electrospraying of Polymer Solutions: Use of Dispersant Flow
Kim, Min-Young ; Lee, Jong-Hwi ;
Polymer Korea, volume 35, issue 3, 2011, Pages 254~259
In electrospraying of polymer solutions, metal sample collectors are often ineffective in fully removing solvent from sprayed particles and recovering redispersable sprayed particles. Herein, a novel electro spraying system, where sprayed particles were dispersed into laminar flow of dispersant (coagulation liquid), was designed for the nano-encapsulation of protein drugs. Chitosan and polyacrylic acid were used as the encapsulation materials. Aggregation of particles could be prevented by using this new electrospraying system, and unimodal size distribution was observed at an applied voltage between 4~16 kV and a low flow rate. The effects of the applied voltage on mean particle size were not significant on the other hand.
Study on Radial Force of Helical Structure for Biodegradable Polymer Stents
Park, Chul-Ho ; Park, Ga-Ram ; Choi, Ji-Yeon ; Park, Kwi-Deok ; Han, Dong-Keun ;
Polymer Korea, volume 35, issue 3, 2011, Pages 260~264
Biodegradable polymeric stents have been issued to replace the existing non-degradable metal stents due to relatively improved biocompatibility and low side effects. Fundamentally, all the stents must possess the desired mechanism strength, especially, compression or radial force to maintain the diameters of expanded vessels. Therefore, this study suggests a helical structure and focused on the relation between the lateral compression and structural factors, Unlike a cylindrical model, the radial force of the helical model is proportional to the thickness and the length to the power of one, whereas the diameter to the power of 1.6. The function obtained from these results might provide the fundamental information to design and prepare the stem for clinical applications.
Syntheses and Characterizations of Functionalized Graphenes and Reduced Graphene Oxide
Moon, Hyun-Gon ; Chang, Jin-Hae ;
Polymer Korea, volume 35, issue 3, 2011, Pages 265~271
Graphene oxide (GO) was prepared by the Hummers and Offeman method from graphite. Reduced graphene oxide (EGO) and functionalized graphenes were synthesized from GO by using hydrazine hydrate and amine-functionalized alkyl groups, respectively. The structures of the GO, EGO, and functionalized graphenes were identified by FTIR and
NMR. In addition, we examined the thermal stability, morphology and dispersibility of the materials in various organic solvents. AFM disclosed that GO and RGO consisted of one- or two-layer graphene regions throughout the film. However, the functionalized graphene films showed average thicknesses of 2.26~3.30 nm, The thermal stability of the functionalized graphenes was poorer than that of the EGO. The functionalized graphenes were well dispersed in toluene or chloroform, as evidenced by the lack of the characteristic graphite reflection in the solutions.
Induction Mechanism of Planar Arrangement in Cholesteric Liquid Crystals
Jung, Gap-Ha ; Lee, Mong-Ryong ; Seo, In-Seon ; Song, Ki-Gook ;
Polymer Korea, volume 35, issue 3, 2011, Pages 272~276
The induction mechanisms of planar arrangements in cholesteric liquid crystals (CLC) which showed selective reflections of visible light were investigated by measuring the selective reflectivity and FTIR peak intensity of
stretching band. Although the planar arrangement of CLC was not as perfectly induced as the cases prepared with using alignment layers, it could be also induced by stretching polymer substrate or by applying shear forces. The planar arrangements were induced by forming CLC helical structures on top of liquid crystal molecules which were in contact with the substrate and oriented all in the same direction.