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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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Simulations of Self-Assembled Structures in Macromolecular Systems: from Atomistic Model to Mesoscopic Model
Huh, June ; Jo, Won-Ho ;
Polymer Korea, volume 30, issue 6, 2006, Pages 453~463
Molecular simulation is an exceptionally useful method for predicting self-assembled structures in various macromolecular systems, enlightening the origins of many interesting molecular events such as protein folding, polymer micellization, and ordering of molten block copolymer. The length scales of those events ranges widely from sub-nanometer scale to micron-scale or to even larger, which is the main obstacle to simulate all the events in an ab initio principle. In order to detour this major obstacle in the molecular simulation approach, a molecular model can be rebuilt by sacrificing some unimportant molecular details, based on two different perspectives with respect to the resolution of model. These two perspectives are generally referred to as 'atomistic' and 'mesoscopit'. This paper reviews various simulation methods for macromolecular self-assembly in both atomistic and mesoscopic perspectives.
Synthesis of Methoxy Poly(ethylene glycol)/Polyesters Diblock Copolymers and Evaluation of Micellar Characterization as Drug Carrier
Hyun, Hoon ; Yang, Jae-Chan ; Kim, Moon-Suk ; Lee, Hai-Bang ; Khang, Gil-Son ;
Polymer Korea, volume 30, issue 6, 2006, Pages 464~470
Diblock copolymers consisting of methoxy Poly (ethylene glycol) (MPEG) and poly (
prolactone) (PCL), poly(
) (PVL), poly(L-lactide) (PLLA), or poly(L-lactide-co-glycolide) (PLGA) were prepared to compare the characterization of diblock copolymers as a drug carrier. MPEG-PCL, MPEG-PVL, MPEG-PLLA, and MPEG-PLGA diblock copolymers were synthesized by the ring-opening polymerization of
-valerolactone in the presence of
as a monomer activator at room temperature and by the ring-opening polymerization of L-lactide or a mixture of L-lactide and glycolide in the presence of stannous octoate at
, respectively. The synthesized diblock copolymers were characterized with
, GPC, DSC, and XRD. The micellar characterization of MPEG-polyester diblock copolymers in an aqueous phase was carried out by using NMR, dynamic light scattering, AFM, and fluorescence techniques. Most micelles exhibited a spherical shape in AFM. Thus, ore confirmed that the micelles formed with MPEG-polyester diblock copolymers have possibility as a potential hydrophobic drug delivery vehicle because a hydrophobic drug could be preferentially distributed in the micelle core.
Effect of the Surface Electrode Formation Method and the Thickness of Membrane on Driving of Ionic Polymer Metal Composites (IPMCs)
Cha, Gook-Chan ; Song, Jeom-Sik ; Lee, Suk-Min ; Mun, Mu-Seong ;
Polymer Korea, volume 30, issue 6, 2006, Pages 471~477
Ion exchange metal composite(IPMC) has toughness equivalent to the range of human's muscle, transformation-actuation force by relatively low voltage and the fast response time. Thus, as a new method for preparing thicker IPMC, the solution casting method to make the films of various thicknesses out of liquid nation was attempted in this study. To reduce the surface resistance of electrode, the first plated electrode prepared by Oguro method was replated with Au and Ir using ion beam assisted deposition(IBAD). The microstructures of electrode surfaces before and after IBAD plating were investigated using SEM. The change of water and ion-conductivity in IPMC were measured under applied voltage. The displacement and driving force of IPMCs with various thicknesses were measured to evaluate the driving properties.
Physical Properties and Flame Retardency of Polyhydroxyamides (PHAs) Having Pendant Groups in the Main Chain
Yoon, Doo-Soo ; Choi, Jae-Kon ; Jo, Byung-Wook ;
Polymer Korea, volume 30, issue 6, 2006, Pages 478~485
Physical properties and flammability of polyhydroxyamides (PHAs) haying poly (ethylene-glycol) methyl ether (MPEG) and/or dimethylphenoxy pendants were studied by using DSC, TGA, FTIR, pyrolysis combustion flow calorimeter (PCFC), and X-ray diffractometer. The degradation temperatures of the polymers were recorded in the ranges of
in air. PCFC results showed that the heat release (HR) capacity and total heat release (total HR) values of the PHAs were increased with in-creasing molecular weight of MPEG. In case of M-PHA 2 annealed at
, the values of HR capacity were siginificantly decreased from 253 to 42 J/gK, and 60% weight loss temperatures increased from 408 to
with an annealing temperature. The activation energy for the decomposition reaction of the PHAs showed in the range of
, which increased with increasing conversion. Tensile modulus of PHAs were decreased as increasing chain of MPEG, and showed an increase more than initial modulus after converted to PBOs.
Preparation and Properties of Heterogeneous Cation Exchange Membrane for Recovery of Ammonium Ion from Waste Water
Jeong, Boo-Young ; Song, Sang-Hun ; Baek, Ki-Wan ; Cho, In-Hee ; Hwang, Taek-Sung ;
Polymer Korea, volume 30, issue 6, 2006, Pages 486~491
Heterogeneous membranes were prepared by compression molding for the recovery of ammonium ion from waste water. Degree of sulfonation for sulfonated ion exchange resin increased with increasing amount of chlorosulfonic acid. It was 3.32 meq/g at 10 vol%. The tensile strength and elongation of the heterogeneous membrane was decreased with increasing contents of ion exchange resin. The tensile strength for LLDPE matrix membrane was the highest and also the elongation for EVA matrix membranes were the highest. The water content of heterogeneous membrane was increased with increasing contents of ion exchange resin. The maximum value of transport number for PE matrix membrane was 0.973. The electrical resistance of LLDPE matrix membrane was the lowest. It was value of
at 70 wt% resins.
Evaluation on Dielectric Properties of Epoxy/Montmorillonite Nanocomposites
Jang, Yong-Kyun ; Kim, Woo-Nyon ; Kim, Jun-Kyung ; Park, Min ; Yoon, Ho-Gyu ;
Polymer Korea, volume 30, issue 6, 2006, Pages 492~497
The epoxy composites are prepared with mixing temperature of epoxy/montmorillonite (MMT) melt master batch and the dielectric properties of the composites are also compared with intercalation of MMT. The exfoliation mainly occurrs iii the low content of MMT composites, while in the composites with high content of MMT the interspacing distance increases as the mixing temperature of epoxy/MMT master batch is increased. Class transition temperature of the composite which the MMT are effectively exfoliated is increased with the appropriate postcuring condition. Since the orientation polarization of dipoles in the epoxy molecules is restricted by the clay nanolayers exfoliated, the dielectric constant and dielectric loss of the composites are reduced. Furthermore, the dielectric properties could be improved by controling the mixing temperature and time of epoxy/MMT master batch as well as postcuring condition.
Preparation of Polystyrene Beads by Suspension Polymerization with Hydrophobic Silica as a Stabilizer in Aqueous Solution
Park, Moon-Soo ;
Polymer Korea, volume 30, issue 6, 2006, Pages 498~504
A suspension polymerization of styrene In aqueous phase was employed to study if polystyrene particles ranging from 1 to
can be produced. Hydrophobic silica was selected as a stabilizer and azo-bisisobutyronitrile (AIBN) as an initiator. Polymerization reaction was carried out at a selected temperature in the range of
. Stabilizer concentration was varied from 0.17 to 3.33 wt% compared to the water while the concentration of the initiator was raised from 0.13 to 6.0 wt% compared to the monomer. Dispersion of hydrophobic silica into the water phase was achieved by precise control of pH. Optimum dispersion of silica was obtained at pH 10. Average particle diameter decreased with increasing amounts of stabilizer concentration initially, exhibiting the minimum average diameter at 1.67 wt% of stabilizer concentration, after which it started to Increase. It is speculated that an excessive presence of stabilizer encouraged a secondary reaction in the reaction medium, which led to particle agglomeration, and as a result an increase in average particle diameter. Molecular weight was found to be independent of stabilizer concentration between 0.13 and 1.00 wt% whereas, it increased when stabilizer concentration exceeded 1.67 wt%. Variation of molecular weight was probably caused by the reduced activity and efficiency of initiator due to the high concentration of silica, and the secondary reaction in the reaction medium, as well. An increase in the Initiator concentration and/or reaction temperature resulted in an increase in both reaction rate and particle diameter. Consequently, we have confirmed that spherical polystyrene particles with
in diameter can be prepared by careful selection of the concentration of stabilizer, initiator, pH and reaction temperature.
Suspension Polymerization with Hydrophobic Silica as a Stabilizer II. Preparation of Polystyrene Composite Particles Containing Carbon Black
Park, Moon-Soo ;
Polymer Korea, volume 30, issue 6, 2006, Pages 505~511
We tried to prepare polystyrene composite particles containing carbon black by suspension polymerization with water as a reaction medium. Hydrophobic silica was selected as a stabilizer and oil-soluble azobisisobutyronitrile (AIBN), as an initiator. All polymerization reactions were carried out at a fixed temperature of
. Stabilizer concentration was varied from
compared to water, where particles with
in average diameter were obtained at 1.57 wt% of stabilizer. Increase in divinylbenzene concentration, as a crosslinking agent, from
compared to monomer exhibited a large increase in average particle diameter Incorporation of 1wt% of carbon black compared to monomer produced an increase in average diameter It is speculated that viscosity lower than that necessary to induce even dispersion of carbon black particles led to poor dispersion, and as a result, large particles. For a styrene mixture containing 3 wt% carton black compared to monomer, enhanced dispersion due to an increase in carbon black concentration reduced average particle diameters. For styrene mixtures containing 1 and 3 wt% carbon black compared to monomer, preparticles before polymerization and polymer composite particles after polymerization showed a similar tendency towards particle formation. When carbon black concentration compared to monomer was increased to 5 and 7 wt%, styrene mixtures exhibited a large increase in viscosity and thus better dispersion of carbon black particles, which led to a decrease in preparticle diameters. However, these particles experienced agglomeration in the polymerization process, and polystyrene composite particles increased in average diameter.
Polymeric Micelle Using Poly((R)-3-hydroxybutyric acid)/Poly(ethylene glycol) Amphiphilic Block Copolymer for Drug Delivery System
Jeong, Kwan-Ho ; Kim, Young-Jin ;
Polymer Korea, volume 30, issue 6, 2006, Pages 512~518
A biodegradable polymer poly((R) -3-hydroxybutyric acid) (PHB) was conjugated with a hydrophilic polymer poly(ethylene glycol) (PEG) by the ttansesterification reaction to form the amphiphilic block copolymer. PHB with low molecular weight (
) was appropriated for the drug delivery materials. High molecular weight PHB was hydrolyzed by an acid-catalyst to produce the low molecular weight one. Amphiphilic block copolymer was formed the self-assembled polymeric micelle system in the aqueous solution that the hydrophillic PEG was wraped the hydrophobic PHB. Generally, polymeric micelle forms the small particle between
. These polymeric micelle systems have been widely used for the drug delivery systems because they were biodegradable, biocompatible, non-toxic and patient compliant. The hydroxyl group of PEG was substituted with carboxyl group which has the reactivity to the ester group of PHB. Amphiphilic block copolymer was conjugated between PHB, and modified PEG at
which was higher than the melting point of PHB. Transesterification reaction was verified with DSC, FTIR,
. In the aqueous solution, critical micelle concentration (CMC) of the mPEG-co-PHB copolymer measured by the fluororescence scanning spectrometer was
. The shape and size of the nanoparticle was taken by dynamic light scattering and atomic force microscopy. The size of the nanoparticle was about 130 nm and the shape was spherical. Our polymeric micelle system can be used as the passive targeting drug delivery system.
Preparation and Evaluation of Poly(vinyl pyridine) Copolymers for Organic Solderability Preservatives
Im, Jeong-Hyuk ; Lee, Hyun-Jun ; Huh, Kang-Moo ; Kim, Chang-Hyeon ; Lee, Hyo-Soo ; Lee, Chang-Soo ; Choi, Ho-Suk ;
Polymer Korea, volume 30, issue 6, 2006, Pages 519~524
Poly(4-vinyl pyridine) (PVP) and its copolymers, poly(4-vinyl pvridine- co-acrylamide) and poly(4-vinyl pyridine-co-allylamine), were synthesized and evaluated for application to organic solder-ability preservatives (OSP). The copolymers were synthesized by radical polymerization of vinyl pyridine in the presence of acrylamide or allylamine as a comonomer. Various kinds of polymers with different chemical composition were synthesized by varying the feed ratio of monomers and their low
polymers can be obtained by adding 2-mercaptoethanol as a chain transfer agent during poly-merization. All the polymers showed good adhesion properties on Cu pad when they were spin-coated. Especially, allylamine -containing copolymers showed both good adhesion and solubility properties. Also, they exhibited better thermal stability than PVP homopolymer and such thermal properties were changed depending on the chemical composition and their
, which were evidenced by the measurement of oxygen induced temperature (OIT). From the OIT measurement, poly(4-vinyl pyridine- co-allylamine) was thermally stable up to
for 70 min in the 100% oxygen environment. As a result, allylamine-containing copolymers can be considered as a promising OSP coating material that has excellent thermal and adhesive properties applicable to the present microelectronic package processes.
Adsorption Properties for Heavy Metals Using Hybrid Son Exchange Fibers with Sulfonated PONF-g-Styrene by Radiation Polymerization and Cation Exchange Resin
Baek, Ki-Wan ; Cho, In-Hee ; Nho, Young-Chang ; Hwang, Taek-Sung ;
Polymer Korea, volume 30, issue 6, 2006, Pages 525~531
In this study, Sulfonated PONF-g-styrene ion exchange fibers were synthesized by radiation induced graft copolymerization. And also, hybride ion exchange fibers, which was combined sulfonated PONF-g-styrene fibers and cationic ion exchange resin, were fabricated by hot melt adhesion method and then their adsorption properties were investigated. ion exchange capacity and water content of hybrid ion exchange fibers increased as compared with those of bead and ion exchange fiber. Their maximum values were 4.76 meq/g and 23.5%, respectively. Adsorption breakthrough time for mercury of hybrid ion exchange fiber was slower than those of bead resin and fibrous ion exchanger. It's value was 130 minutes. Their breakthrough time become short as increasing of pH, and concentration. The initial breakthrough time was observed before and after 10 minutes as increasing of concentration. The adsorption of hybrid ion exchange fibers for
among heavy metals in the mixed solution was observed before 20 min. And also, The adsorption for
among the heavy metals by hybride ion exchange fibers was observed.
Preparation and Properties of Celluose Diacetate/Starch Composite
Lee, Sang-Yool ; Lee, Seung-Kyung ; Lim, Hwan-Kyu ; Kye, Hyoung-San ; Lee, Young-Kwan ;
Polymer Korea, volume 30, issue 6, 2006, Pages 532~537
In order to successfully meet the environmental and recycling problems, natural polymer and their derivatives are recognized as a promising biodegradable material. In this study, the biodegradable composites of cellulose diacetate and starch were prepared, and their physical and thermal properties were investigated. For the melting processing, triacetine was added as a plasticizer into the composites. The processability of cellulose diacetate was further enhanced by increasing the amount of starch in the composites. The tensile stress and Young's modulus were decreased and elongation was increased with increasing the amount of starch in them. A
value was decreased with increasing the amount of starch in the composites. Also, the morphology of the composites were observed with the SEM.
Synthesis of Novel Prepolymers Containing No Bisphenol A and Preparation of Organic Matrices for Dental Applications
Son, Jun-Sik ; Lee, Ki-Baek ; Park, Kwi-Deok ; Kim, Jae-Jin ; Ahn, Kwang-Duk ; Kim, Jung-Hyun ; Han, Dong-Keun ;
Polymer Korea, volume 30, issue 6, 2006, Pages 538~544
Two kinds of novel bifunctional methacrylated prepolymers (170-2MA and 631-2MA) which have similar structure with 2,2-bis[4- (2'-hynroxy-3'-methacryloyloxypropoxy)phenyl] propane (Bis-GMA) was synthesized for dental applications as an alternative to Bis-GMA containing bisphenol A that is doubtful as an endocrine disrupter. The organic matrices were prepared by mixing a diluent and/or a monomer with the synthesized methacrylated prepolymers. The yield, viscosity, and chemical structures of the prepolymers and the physical and methanical properties of the organic matrices were evaluated. The yields of the prepolymers synthesized through a ring-opening reaction of epoxy compound and methacrylic acid were above 90% and the viscosities of the prepolymers were much lower than that of the Bis-GMA control. From the results of
and FTIR analyses, the chemical structures of the prepolymers were similar to that of Bis-GMA. In addition, the curing time, poly-merization shrinkage, photoconversion, polymerization depth, and compressive strength of the organic matrices formulated with 170-2MA and 631-2MA prepolymers exhibited comparable to or better than those of the existing Bis-GMA-based one. These results suggest that the novel methacrylated prepolymers which have no endocrine disrupter can be an alternative to Bis-GMA and be applicable to dental polymer materials.
Poly(vinyl alcohol) Nanocomposite Films (II): Thermo-mechanical Properties and Morphology
Ham, Shin-Kyun ; Jung, Min-Hye ; Chang, Jin-Hae ;
Polymer Korea, volume 30, issue 6, 2006, Pages 545~549
Blends of poly(acrylic acid- co-maleic acid) (PAM) with poly (vinyl alcohol) (PVA) were pre -pared in distilled water PVA/PAM/saponite (PVA/PAM/SPT) nanocomposite films were prepared with various clay contents by using the solution intercalation method. The variations of the dispersion, morphology, and thermo-mechanical properties of the nanocomposites with clay content in the range 0 to 9 wt% were examined. Up to 3 wt% clay loading, the clay particles were homogeneously dispersed in the PVA/PAM blends. However, some agglomerated structures form in the polymer matrix above a clay content of 7 wt%. The thermal stability of the hybrids was increased linearly with increasing the clay loading up to 9 wt%. The maximum strength and modulus were obtained at a clay content of 7 wt%. Thus, the addition of small amounts of clay to the PVA/PAM blends produced PVA/PAM nano-composites with improved the thermo-mechanical properties.
Change of Ink Absorption Characteristics of Ink-Jet Printing Paper with Polymeric Binder
Kim, Chul-Yong ; Lee, Myung-Cheon ;
Polymer Korea, volume 30, issue 6, 2006, Pages 550~555
The coating material for the ink-jet printing paper tends to be waterbase as the waterbase ink-jet ink is used more widely. Waterbase coating material consists of alumina sol as a pigment, poly(vinyl alcohol) as a main binder and polymeric additive for improving properties. In this study, polymeric auditive was synthesized by combining one or toto monomers among methacrylic acid, acrylic acid and acrylamide to the basic monomers, styrene and n-butylacrylate. The properties of printability such as ink absorption, ink spreading, and optical density, glossiness and water resistance were investigated by changing the kinds of surfactants, the composition of monomers and the structure of polymer particles. Results showed that materials containing anionic surfactant and/or acrylic acid had problems in com-patibility with alumina sol. Also, coating materials containing acrylamide had good printability and lout glossiness while those containing methacrylic acid did not have good printability and high glossiness.
Synthesis of Almost Fully Quavternized Poly(4-vinylpyridine)s by Polymer Reaction and Aggregation Property with Sodium Dodecyl Sulfate
Sim, Hoo-Sik ; Choi, E-Joon ; Kim, Young-Chul ; Park, Il-Hyun ;
Polymer Korea, volume 30, issue 6, 2006, Pages 556~562
Quarternized poly(4-vinyl pyridine)s have been prepared by the reaction of poly (4-vinyl pyridine)s (Mw=50 kg/mol and 200 kg/mol) and alkylating agents varying the carbon numbers of the alkyl groups (m):dimethyl sulfate (m=1) as well as bromoalkane (m= 5, 8, 12, 16, and 22) was used as an alkylating agent. The degree of alkylation was determined by using an elemental analysis and NMR spectroscopy. As a result, polyelectrolytes were obtained by the almost full alkylation of poly (4-vinyl pyridine)s. The critical aggregation concentration (CAC) was determined by measuring the change of turbidity occurred by addition of sodium dodecyl sulfate (SDS) into aqueous solution of quarternized poly-(4-vinyl pyridine)s, and the dependence of molecular weight of polymer, the length of N-alkyl group and concentration of NaCl upon CAC was investigated. As a result, as the molecular weight or the length of alkyl group was increased, less amount of SDS Gould induce the aggregation.
Morphology and Swelling Behaviors of PVA/Gelatin Blend Membranes Prepared Under High Electric Field
Huh, Yang-Il ; Yun, Hyung-Ku ;
Polymer Korea, volume 30, issue 6, 2006, Pages 563~567
Poly(vinyl alcohol) (PVA) and gelatin (GEL) blend membranes were prepared by solution casting method under a high electric field. SEM observation of the membrane showed that gelatin rich domains were elongated and oriented to the direction of the applied electric field in PVA matrix. This can be attributed to the electrostatic emulsifying effects due to a reduction in interfacial tension. In addition, it was observed through WAXD and swelling measurements that the degree of crystallinity of membranes increased with applied electric field strength. This may be interpreted to be caused by the orientation effect of GEL domains in the blend membrane, and the self-annealing effect due to some heat generated from high electric field during casting.
Ion Permeation of PVA/Gelatin Blend Membrane Prepared Under High Electric Field
Huh, Yang-Il ; Joe, Jeong-Woong ;
Polymer Korea, volume 30, issue 6, 2006, Pages 568~571
Poly(vinyl alcohol) (PVA)/gelatin(GEL) blend membranes were prepared under a high electric field, and their swelling and ion permeation behaviors were investigated. For alkali metal salts such as LiCl, NaCl and KCl, the permeability coefficients were increased until the electric field of 10 kV due to the decreased tortuosity, whereas they were decreased over 10 kV owing to the increase of the degree of crystallinity. The swelling ratios of the blend membranes showed the minimum values at pH 6, while the permeability coefficients exhibited the maximum values at the same condition. The minimum swelling ratios result from the repulsion effect between charged groups in acidic or basic regions, and the maximum permeabilities result from Donnan exclusion effect in the same regions. Especially, the per-meability coefficient for KCl of the membrane increased steeply to five times at
Development of Jelly-Type Simulating Polymer Based Human Tissue for Research on Hyperthermia by High Frequency Magnetic Field
Kim, Oh-Young ; Choi, Chang-Young ; Ma, Sung-Jae ; Lim, Sang-Mung ; Seo, Ki-Taek ;
Polymer Korea, volume 30, issue 6, 2006, Pages 572~575
In this work, a variety of polymer based jelly phantoms suitable for the hyperthermia operations to human organs was synthesized in order to confirm the possibility of auxiliary cancer therapy. Specifically, using an appropriate material composition including polyethylene, Jelly phantoms for brain was prepared and characterized their electrical properties suitable for the monitoring the effect of electromagnetic wave from code division multiple access (CDMA) and personal communication service (PCS) on the human body. In the future, after injection of ferromagnetic nanoparticle into the jelly phantoms, new approach to propose the cancer therapy can be anticipated by monitoring the degree of temperature rise in human body using the photograph of Infrared camera.