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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
The Polymer Society of Korea
Editor in Chief :
Volume & Issues
Volume 25, Issue 6 - Nov 2001
Volume 25, Issue 5 - Sep 2001
Volume 25, Issue 4 - Jul 2001
Volume 25, Issue 3 - May 2001
Volume 25, Issue 2 - Mar 2001
Volume 25, Issue 1 - Jan 2001
Selecting the target year
Synthesis and Characterization of Poly(ethylene oxide) Derivatives Containing Carbonate Linkages
Polymer Korea, volume 25, issue 6, 2001, Pages 759~764
In order to obtain PEO with reduced crystallinity, novel PEO derivatives containing carbonate linkages in the main chain have been synthesized by the reaction of various molecular weight poly (ethylene glycol)s (PEGs) with dimethyl carbonate (DMC) in the presence of
to yield methyl carbonate terminated PEGs, followed by condensation reaction under vacuum in the presence of titanium isopropoxide (TiP) catalyst. The number average molecular weight of PEGs used was in the range of 200 and 600 g/mol. The structure and compositions of the resulting polymers were characterized by
. Their thermal behavior and molecular weight were characterized by DSC/TGA and GPC, respectively
Synthesis of Multifunctional AN-co-(MMA/IA) Fibrous ion-exchanger by Hydrolysis and Adsorption Properties for Trace Transition Elements
Polymer Korea, volume 25, issue 6, 2001, Pages 765~773
In In order to remove harmful trace elements such as
from water, we synthesized AN-co-(MMA/IA) according to various mole ratio of monomers and spun by wet-spinning. And multi-functional PAN ion exchangers were prepared by hydrolysis. We observed structure, degree of functionalization, ion exchange capacity, distribution coefficient and mechanical properties for ion exchanger. Anion exchange capacity decreased in 4.5 ~ 4.2 meq/g with increasing of IA content and cation exchange capacity increased in 1.8 ~ 2.2 meq/g. Tensile strength of the ion exchanger increased up to 0.008 mol% IA content and appeared maximum value by 216
Distribution coefficient for AN-co-(MMA/IA) ion exchanger appeared maximum value for Co(II), Ni(II) in pH 5-6 range and for Cr(III) in pH 3-4 range. And the adsorption capacity was in the order of Cr(III) > Co(II) > Ni(II) for multicomponent in continuous process.
Fabrication and Mechanical Properties of the Hybrid Composites Filled with Waste Stone and Tire Powders
Polymer Korea, volume 25, issue 6, 2001, Pages 774~781
In order to reuse the waste matters, the polyester hybrid composites were fabricated with the waste stone (WSP) and waste tire (WTC). Before mixing, the waste fillers were treated with the silane coupling agent [
-methacryloxy propyl trimethoxy silane(
-MPS)] for enhancing the dispersion of the fillers and interfacial bonding with polymer matrix. Mechanical properties and morphologies of the resulted hybrid composites were investigated with the filler content. The hybrid composites containing surface treated fillers have high initial thermal decomposition temperature and low weight loss compared to the untreated one. The highest mechanical properties of composites were obtained with the
-MPS (2 wt%) treated fillers. The porosity of composite increased with the content of organic filler which can be reduced by the silane surface treatment of fillers. The pore size distribution of the composites varied with the waste filler content.
Electrochemical Characteristics at Copolymeric film Electrodes of [Ru(v-bpy)
and Vinylbenzoic Acid Modified with Dopamine
Polymer Korea, volume 25, issue 6, 2001, Pages 782~788
and vinylbenzoic acid (vba) were electrochemically copolymerized to afford electrodes modified with dopamine to study their properties such as electropolymerization rate, redox process, and electron transfer. The optimum mole ratio of the monomers was 5:2, which gave
of rate constant for first order reaction, while the ratio of the substances on the copolymeric film produced was 5:1.68. The formal potential produced from the hydroquinone=quinone+
reaction at the electrode of GC/p-
/vba-dopamine was 0.17 V in phosphate buffer (pH=7.10). The electrocatalytic rate was
;2.41 times faster than that of non-modified one. The mass change measured by EQCM was
which is larger than that of non-modified one.
Synthesis of Pan Fibrous ion-Exchanger by Hydrolysis and Their Adsorption Properties for Nickel Ion
Polymer Korea, volume 25, issue 6, 2001, Pages 789~795
In order to recover nickel ion from waste water containing heavy metals, the PAN fibrous ion-exchanger with primary, secondary amine groups and carboxyl group was synthesized by acid and base hydrolysis. The hydrolysis yield of PAN fiber in acid solution was higher than base solution. The swelling ratio and ion-exchange capacity of PAN fiber which was synthesized in 1N
for 7 hrs appeared 71.2% and 1.95 meq/g respectively. We investigated that the adsorption of nickel ion was approached 1.44 meq/g at 50 min and the maximum adsorption capacity of ion-exchanger was 2.48 meq/g. We confirmed that the
adsorption ability of the synthesized PAN fibrous ion-exchanger in this study is excellent.
Synthesis of Polybenzimidazole Containing Bulky Side Group
Polymer Korea, volume 25, issue 6, 2001, Pages 796~802
Novel monomer for polybenzimidazole was prepared and polymerized via aromatic nucleophilic substitution reaction. Thus, N-(4-fluorobenzoyl)-4-methoxy-N'-naphthyl-1,2-phenylenediamine was synthesized from the reaction of 4-methoxy-N-naphthyl-1,2-phenylenediamine and 4-fluorobenzoyl chloride. N-(4-fluorobenzoyl)-4-methoxy-N'-naphthyl-1,2-phenylenediamine was converted to 2-(4-fluorobenzoyl)-5-hydroxy-1-naphthylbenzimidazole by ring closure and demethylation reaction. Polymerization was done in N-cyclohexyl-2-pyrrolidinone (CHP) containing potassium car bonate. The resulting polymer was soluble in N-methyl-2-pyrrolidinone (NMP) and had inherent viscosity of 0.38 dL/g (NMP at
). The glass transition temperature (
) of the polybenzimidazole was
. The thermogravimetric analysis (TGA) thermograms of this polymer showed 5% weight losses at
in nitrogen and at
Synthesis and Properties of Hyperbranched Polyester with Second-Order Outical Nonlinearity
Polymer Korea, volume 25, issue 6, 2001, Pages 803~810
A nonlinear optical hyperbranched polyester (PE-Azo/Hyper) was synthesized from 4-[N,N-bis(hydroxyethyl)amino-4'-formyl] azobenzene and cyanoacetic acid by a Knoevenagel polycondensation using 4-(dimethylamino) pyridine as a base. The resulting polymer was soluble in polar aprotic solvents such as N,N-dimethylformamide and 1-methyl-2-pyrrolidinone and could be processed into optical quality films by spin coating. The molecular weight was determined to be
) by gel permeation chromatography using polystyrene as a standard. No melting point was detected by differential scanning Calorimeter, indicating that this polymer presents an amorphous state. It shows a glass transition temperature of
. The second-order nonlinear optical coefficient
of the poled polymer determined by the second harmonic generation at 1064 nm was 25.4 pm/V.
Solvent Induced Crystallization of Polycarbonate in Mixed Solvent
Polymer Korea, volume 25, issue 6, 2001, Pages 811~817
Crystallization behaviour of bisphenol A polycarbonate(PC) from amorphous phase was studied by varing solvent/nonsolvent ratios in liquid phase. Chloroform and isopropanol were used as a solvent and a nonsolvent, respectively. Samples were characterized by optical microphotography, scanning electron microscope (SEM), X-ray diffaction (XRD), and differential scanning calorimeter (DSC). DSC and XRD measurement were used to determine the crystallinity of PC. The solubility constant seems to critical to control the PC crystallinity in solvent/nonsolvent mixture. The difference in PC crystallinity is explained by the difference in solubility constant of the mixture depending on the solvent/nonsolvent ratio. PC solution of 75/25 wt% (solvent/nonsolvent) ratio produced PC powder showing maximum crystallinity. At this condition solubility constant (9.85) of the mixed solvent was close to PC (9.9).
Intercalation of Polycarbonate/Montmorillonite Nanocomposites
Polymer Korea, volume 25, issue 6, 2001, Pages 818~825
Polycarbonate(PC)/montmorillonite (MMT) nanocomposites were prepared by solution and melt mixing methods. A d-spacing of the nanocomposites was measured by an X-ray diffractometer. Neat montmorillonite (MMT-Na) and MMTs modified by dodecyl ammonium (MMT-DA) or dimethyl hydrogenated tallow 2-ethylhexyl ammonium (MMT-25A) were used. The d-spacing value of PC/MMT-25A and PC/MMT-DA was higher than that of PC/MMT-Na. The d-spacing increased from around 12 to
depending on the mixing method. PC was more readily introduced to the gallery of MMT as the molecular weight of PC reduced and the mixing time increased. PC/MMT-25A showed higher thermal stability by thermogravimetric analysis (TGA) than PC/MMT-DA and PC/MMT-Na.
Preparation and Characterization of Polypyrrole Electroactive Actuators
Polymer Korea, volume 25, issue 6, 2001, Pages 826~832
In this study, PPy/gold/mylar type electroactive bi-layer actuator was prepared by the electrochemical polymerization of pyrrole onto the gold/mylar film and the actuation characteristics were studied using bending beam method. Conducting polymer-based actuators undergo volumetric changes due to the movement of dopant ions into the film during the electrical oxidation process. The bilayer films exhibited different actuation characteristics depending on dopant ion size. It was observed that the relatively small dopant ion (i.e. toluene sulfonate) moved into the PPy film at oxidized state, so volume expanded to result in bending motion. In case of the film having large dopant ion (i.e. dodecylbenzenesulfonate), volume expansion was observed at reduced state. This is due to the incorporation of
counterion with water molecules, while the large dopant ion was fixed in the film due to the limited mobility during tile redox process.
Crystallization Characteristics of Metallocene Low Density Polyethylene
Polymer Korea, volume 25, issue 6, 2001, Pages 833~839
The crystallization characteristics of metallocene linear low density polyethylene was investigated by small angle light scattering and comparison was made with Ziegler-Natta linear low density polyethylene. The special efforts were made to find out the effects of branching number, length of branching and co-monomer content of m-LLDPE on the crystallization behavior of m-LLDPE. It was found that m-LLDPE has longer induction time to start crystallization from the amorphous state than that of conventional LLDPE with similar branching number, but the rate of crystallization seems not change much in both LLDPEs. Lowering of branching number in m-LLDPE resulted in both increasing of rate of crystallization and reducing induction time to crystallize. In general, the maximum size of spherulites of m-LLDPE is bigger than that of conventional LLDPE.
Crystallization Characteristics of Metallocene Low Density Polyethylene/Low Density Polyethylene Blends
Polymer Korea, volume 25, issue 6, 2001, Pages 840~847
The crystallization characteristics of metallocene linear low density polyethylene (m-LLDPE)/linear low density polyethylene (LLDPE) blends were investigated. The effect of blending on the induction time for crystallization, spherulites growth rate, and maximum size of spherulites was mainly considered in this study. The formation of separate crystal which is well known crystallization behavior in LLDPE/LDPE blend was not found in m-LLDPE/LLDPE blends. The blending m-LLDPE to LLDPE caused the dramatic decrease in the induction time of m-LLDPE/LLDPE blends but it seems that the blend composition shows less effect on the induction time. Lower branching number in m-LLDPE resulted in the increasing of spherulites growth rate and the maximum size of spherulites is depend upon both the induction time and spherulites growth rate of LLDPE component affected by m-LLDPE.
Crystallization Behavior of Poly(ethylene terephthalate)/Ethylene-Methyl acrylate-Glycidyl methacrylate Copolymer Blend
Polymer Korea, volume 25, issue 6, 2001, Pages 848~854
The crystallization behavior of poly (ethylene terephthalate) (PET) /ethylene-methyl acrylate-glycidyl methacrylate copolymer (E-MeA-GMA) blend was studied. The extent of reaction and the reaction rate between PET and E-MeA-GMA were measured with torque rheometer, FT-IR and SEM. The effects of the grafting reaction on the crystallization behavior were investigated with DSC and time-resolved light scattering (TR-LS) techniques. The morphological change at the lamellar level was also examined by using a small angle X-ray scattering (SAXS) method.
Optimization Condition for Injection Molding of TV Speaker Grille Using CAE
Polymer Korea, volume 25, issue 6, 2001, Pages 855~865
The optimization condition of injection molding for a commercial product of TV speaker grille of A Company was induced using a CAE software of Moldflow. The flow and packing phase analysis was performed by using flow balance, runner balance, and the intermediate one by using the above two balances, which were used for controlling the amount of packing resins into the cavity, Later, the analysis performed by using the measured viscosity (local database) at various shear rates and the results were compared with the computer simulation using the standard database. Flow balance induced minimized weld line resulted in a better appearance and physical properties of the were line, but exhibited a disadvantage of large deformation and gas formation due to over-packing of the molten resin in the center of the speaker grille. Runner balance improved the disadvantage of the flow balance by controlling the amount of molten resin injected from the gate, however resulted reduced mechanical properties and poor appearance of the weld line. However, the modified method induced from the flow and runner balance improved the disadvantages by changing the runner size. In addition, the analyses based on the local database and the standard database were compared. Although the measured viscosity was slightly higher and the temperature distribution was broader than the standard database, no distinct difference was obtained from the analysis using the two different databases.
Influence of Oxidation Inhibitor on Carbon-Carbon Composites : 8. Studies on Thermal Decomposition Mechanism and Thermal Stability of Composites Impregnated with TEOS
Polymer Korea, volume 25, issue 6, 2001, Pages 866~875
In this work, thermal decomposition mechanism based on kinetic parameters and thermal stability of carbon fiber-reinforced carbon matrix composites (C/C composites), have been studied under high temperature oxidative conditions with addition of tetra-ethylorthosilicate (TEOS) as an oxidation inhibitor. Thermogravimetric analysis (TGA) was executed to evaluate the thermal decomposition mechanism and thermal stability of C/C composites in the temperature range of 30 ～
. As a result, the kinetic parameters of the composites impregnated with TEOS, i.e., activation energy for thermal decomposition (
), order of reaction (n) , and pre-exponential factor (A) were evaluated as 136 kJ/mol, 0, and 2.3
, respectively. Especially, the IPDT and
of C/C composites impregnated with TEOS were improved largely compared with the composites impregnated without TEOS, due to the formation of
on composite surfaces, resulting in interrupting the oxygen attack to carbon active site in the composites.
Synthesis and Characterization of Organo-Clay Based Thermotropic Liquid Crystalline Polyester Nanocomposites
Polymer Korea, volume 25, issue 6, 2001, Pages 876~883
A thermotropic liquid crystalline polyester (TLCP) containing a side group was, synthesized from ethoxyhydroquinone and bromoterephthalic acid. Intercalation of TLCP in layered clays is accomplished by heating the polymer with hexadecyl ammonium-montmorillonite (
) above melting transition temperature (
). Liquid crystallinity of the TLCP/
-hybrid was observed up to 6 wt%
-MMT. Some of the
-MMTs in TLCP were highly dispersed in a nanometer scale, but some of them were agglomerated. Thermal and morphological properties of the nanocomposites were examined by differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA), polarized optical microscope, and electron microscopes (SEM and TEM).
Characteristics of Nifedipine Loaded PLGA Wafer
Polymer Korea, volume 25, issue 6, 2001, Pages 884~892
Biodegradable wafers were prepared with poly (L-lactide-co-glycolide) (50 : 50 mole ratio of lactide to glycolide, molecular weight:5000 g/mole) by direct compression method for the sustained release of nifedipine to investigate the possibility of the treatment of hypertension. PLGA wafers were prepared by altering initial drug/polymer loading ratio, wafer thickness, and hydroxypropyl methylcellulose (HPMC) content. These wafers showed new zero-order release patterns for 11 days, and various biphasic release patterns could be obtained by altering the composition of wafers such as addition of matrix binder as HPMC to the PLGA wafer to reduce release rate of initial phase. The onset of polymer mass loss only occured after 4 days and about 40% of mass loss was observed after 11 days nifedipine release. This system had advantages in terms of simplicity in design and obviousness of drug release rate and may be useful as an implantable dosage form.
Preparation and Release Profile of N8f-loaded Polylactide Scaffolds for Tissue Engineered Nerve Regeneration
Polymer Korea, volume 25, issue 6, 2001, Pages 893~901
We developed the nerve growth factor (NGF) loaded poly (L - lactide) (PLA) scaffolds by means of emulsion freeze drying method to the possibility for the application of the nerve regeneration of spinal cord disease and the degeneration in Alzheimer's disease. The release amount of NGF from NGF loaded PLA scaffold were analyzed over a 4 week period in vitro at phosphate buffered saline (PBS), pH 7.4, at
. It can be observed the open cell pore structure of porous scaffolds and can be easily controlled the pore structure by the controlling of formulation factors resulting in the controlling of the release rate and the release period. The stability of NGF during the preparation of PLA scaffold was evaluated by comparing the released amounts of total NGF, assayed NGF enzyme - linked immunosorbent assay (ELISA). Released NGF has been found to enhance the neurite sprouting and outgrowth from pheochromocytoma (PC-12) cells. These results suggest that the released NGF from NGF loaded PLA scaffold such as conduit type can be very useful for the nerve regeneration in the neural tissue engineering area.