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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 of Aminated GMA-DVB Copolymer and Their Adsorption Properties for Nitrate
Polymer Korea, volume 25, issue 3, 2001, Pages 311~317
In this study, we synthesized bead-type GMA-DVB copolymer using glycidylmethacrylate (GMA) with high reactivity and hydrophilicity. Macrorecticular anion exchanger containing the trimethylammonium group were then prepared by amination with trimethylammonium chloride. We observed that the size of
is smaller than that of
removal in most of coexistent anions in ground water. Thus we investigated selective affinity for
and properties of individual ion exchangers with various DVB content. For each resins, we confirmed formation of copolymer by FT-IR spectrometer and investigated ion exchange capacity, swelling ratio, the amination yield and the effect with degree of crosslinking on adsorbability for nitrate. When amount of DVB is 4 wt%, amination yield, ion exchange capacity and swelling ratio was 384.3%, 3.25 meq/g and 77.1%, respectively. In these result, it can found that synthetic optimal condition is 4 wt% DVB content for monomer.
Fabrication and Characterization of Porous PLLA Scaffolds with Gentamicin Sulfate Release System
Polymer Korea, volume 25, issue 3, 2001, Pages 318~326
PLLA scaffold loaded with gentamicin sulfate (GS) was prepared by emulsion freeze-drying method for the prevention of infection and the improvement of wettability. i.e., the cell- and tissue-compatibility. GS-loaded PLLA scaffolds were characterized by scanning electron microscopy (SEM), mercury porosimetry and blue dye intrusion, and the GS release pattern was analyzed by high performance liquid chromatography (HPLC). GS-loaded PLLA scaffolds with porosity above 50%, medium pore size ranging from 30 to 57
(with larger pore diameters greater than 150
), and specific pore area in the range of 35 to 75(
/g )were manufactured by varying processing parameter as GS concentration. It was observed that GS-loaded PLLA scaffolds were highly porous with good interconnections between pores for allowing cell adhesion and growth. These scaffolds may be applicable for scaffold as structures that facilitate either tissue regeneration or repair during reconstructive operations.
Thermal and UV Curing of Vacuum Deposited Film of Acetylene Substituted Fluorenes
Polymer Korea, volume 25, issue 3, 2001, Pages 327~333
Acetylene substituted fluorenes such as 2-ethynylfluorene and 2,7-diethynyl-fluorene were synthesized and thin films were prepared by the vacuum deposition. Curing of these fluorene derivatives could be achieved by heat treatment and UV irradiation. The curing temperature of 2-ethynylfluorene and 2,7-diethynylfluorene were found to be 231 and
, respectively. The cured poly(2-ethynylfluorene) and poly(2,7-diethynylfluorene) started to decompose at 280 and
, respectively. Fluorescent characteristics of the cured films were similar to those of monomers, but fluorescent efficiency of the film was decreased about 3 to 10 fold.
Preparation of Biodegradable PHBV Devices Containing Gentamicin Sulfate
Polymer Korea, volume 25, issue 3, 2001, Pages 334~342
Gentamicin sulfate (GS)-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) devices were prepared for controlled-release of antibiotics. In this study, the effects of thickness, hydroxyvalerate (HV) content, initial drug-loading ratio, and additive content on the release profile have been investigated. The morphology of devices was examined with scanning electron microscope (SEM) before and after in vitro release; their highly porous surface and cross-sectional were observed. It could be suggested that device would be affected by the packing of the HV and additive content, which would depend on their structure. A high performance liquid chromatography (HPLC) was used to detect and quantify the release of GS from the device. The drug release from all the devices showed biphasic release patterns, and some matrices released the incorporated antibiotic throughout 30 days with a near zero-order release rate. The release patterns were shown to be changed by altering the thickness, copolymer ratio, and additive content.
A Study for Mechanical and Platelet Adhesion Properties of Fluorinated Polyurethanes
Polymer Korea, volume 25, issue 3, 2001, Pages 343~348
The mechanical and the platelet adhesion properties of the fluorinated polyurethane elastomers synthesized with a perfluorinated polyether diol (Fomblin ZDOL
) and 4,4'-diphenyl methane diisocyanate (MDI) were investigated. The change of mechanical properties with the Fomblin content and the type of the polyether diol was investigated by applying a designed technique using in vitro platelet adhesion test. As a result, the tensile properties were affected by the content and the type of nixed polyether diols. Also the platelet adhesion of polyurethane elastomers decreased with increasing the extent of fluorination in the polymer.
Synthesis and Behavior of Silyl Group-Containing Acrylic Resins as Weather Resistant Coatings
Polymer Korea, volume 25, issue 3, 2001, Pages 349~358
Silyl group-containing acrylic resins were synthesized to prepare weather resistant coatings. Acrylic copolymer was synthesized by the addition copolymerization of n-butyl methacrylate, methyl methacrylate, n-butyl acrylate and 3-methacryloxypropyl trimethoxysilane (MPTS). Acrylic copolymer were synthesized such that their
's were adjusted to
and their MPTS contents were varied to 10, 20 and 30 wt%. As the content of MPTS increased, viscosity of coatings increased and thermal stability at the high temperature was improved. Coatings was prepared by blending the synthesized resins with a white pigment. The adhesion performance of coatings was superior with various substrates and their other properties were on the whole suitable. Weatherability was tested by outdoor exposure test, WOM test and QUV test. It was proved that resin with 30 wt% MPTS was suitable as the binder for weather resistant coatings.
Properties of a Thermosetting Epoxy Composite : Effect of Isothermal Physical Aging
Polymer Korea, volume 25, issue 3, 2001, Pages 359~366
Isothermal physical aging of a glass fiber/epoxy composite was examined at different aging temperatures (
) and degrees of conversion (monitored by the glass transition temperature,
) by means of the TBA torsion pendulum technique. The range of aging temperature was from 10 to
: the conversion was systematically changed from
(fully crosslinked). The effect of isothermal physical aging was manifested as perturbations of the modulus and mechanical loss vs. temperature in the vicinity of
for all conversions. The rate of isothermal physical aging determined from the change of modulus with aging time at fixed aging temperature decreased and then increased with increasing conversion below T
. There exists a superposition in aging rate vs. (
) by shifting horizontally and vertically. This implies that the physical aging process is independent of the change of chemical structure as conversion proceeds. It has been found that water absorbed at the aging temperature below
during isothermal physical aging lowers the apparent aging rate. It is due to the absorbed water molecules forming strong polar interactions with hydroxyl group on network chain and reducing the segmental mobility during the physical aging.g.
Effectiveness of Electromagnetic Interference Shielding of Carbon Nanofiber/Poly(vinylidene fluoride) Composites as a Function of Beat Treatment Temperature and Time
Polymer Korea, volume 25, issue 3, 2001, Pages 367~374
The electromagnetic interference (EMI) shielding effectiveness (SE) of poly(vinylidene fluoride) (PVDF) composites was investigated using carbon nanofiber fillers prepared by catalytic chemical vapor deposition of various carbon-containing gases over Ni and Ni-Cu catalysts. The electrical conductivity of carbon nanofiber which was regarded as the key property of filler for the application of EMI shielding ranged from 4.2 to 22.4 S/cm at a pressure of 10000 psi. The electrical conductivity of carbon nanofiber/PVDF composites ranged from 0.22 to 2.46 S/cm and the EMI SE of those was in the range of 2∼13 dB. The electrical conductivity of carbon nanofibers increased with the increase in heat treatment temperature and time, while the electrical conductivity of the composites increased rapidly at the initial heat treatment and then approached a certain value with the further increase of heat treatment. The SE of the composites showed a maximum at the medium heat treatment and was proportional to the electrical conductivity of the composites. It was concluded that the specific surface area of carbon nanofibers decreased with the continual heat treatment and the specific surface area of filler was an important factor for the SE of the composites.
Effect of Vinylic Monomers on Toughness of Unsaturated Polyester
Polymer Korea, volume 25, issue 3, 2001, Pages 375~384
We investigated the change of mechanical properties of UP using mixture of SM with VAc or MA that have low glass transition temperature when polymerized instead of SM only for diluents of UP. In case of using mixture of SM/MA, it was elucidated that the toughness of UP was more improved than using SM only. But in case of SM/VAc, it was observed that the content of mixture could not affect on toughness. It was concluded that these results are caused by the effect of each diluents mixtures on stress-relaxation due to phase separation and on decrease glass transition temperature of UP is quite different from each other.
Anti-thrombogenicity and Surface Structure of a Poly(ester-ether) Consisting of Poly(L-lactic acid) and Poly(oxyethylene-co-oxypropylene)
Polymer Korea, volume 25, issue 3, 2001, Pages 385~390
The A-B-A type block copoly(ester-ether)s consisting of poly(L-lactic acid) (PLLA)(A) and poly(oxyethylene-co-oxypropylene)(B) were prepared to improve the mechanical properties and hydrolyzability of PLLA. The block copolymers showed an improved flexibility due to the incorporation of the soft segments. Then, the same copolymer has an improved anti-thrombogenicity probably due to the specific microphase separation structure in the surface. The AFM of the film of the block copolymer revealed that the surface was quite flat in comparison with that of PLLA. Therefore, the flatness of the surface may be related with the increased anti-thrombogenicity of the copolymer film.
Synthesis and Characterization of PU Flame-Retardant Coatings Using Tribromo Modified Polyesters
Polymer Korea, volume 25, issue 3, 2001, Pages 391~398
Two-component polyurethane (PU) flame-retardant coatings were prepared by blending tribromo modified polyesters (
) and isocyanate.
were synthesized by condensation polymerization of tribromoacetic acid, a flame-retardant component, with 1,4-butanediol, adipic acid, and trimethylolpropane. The content of tribromoacetic acid was varied by 10, 20, and 30 wt% for the reaction. Various physical properties of these new flame-retardant coatings were comparable to nonflame-retardant coatings. Coatings with 20 wt% tribromoacetic acid did not burn during the vertical burning test.
Change in Opto-electrical Characteristics in Poly[3-octylthiophene-co-3-(4-fluorophenyl)thiophene] according to the Copolymerization Ratio
Polymer Korea, volume 25, issue 3, 2001, Pages 399~405
Poly[3-octylthiophene-co-3-(4-fluorophenyl)thiophene]s were synthesized in 2:1, 1:1, and 1:2 mole ratios, and organic electroluminescent devices were fabricated using the copolymers. The opto-electrical properties of the copolymers were studied by PL, EL spectra, I-V, and V-L curves of the organic electroluminescent devices in conjunction with the energy band diagrams which were obtained from the cyclic voltammogram and the electronic absorption spectra. The LUMO energy level of P(OT/FPT)(1:1) is the lowest as -3.35 eV. In the copolymers P(OT/FPT)(2:1) and P(OT/FPT)(1:1) the
in the PL and EL spectra red-shifted as the mole ratio of fluorophenyl group increased while in P(OT/FPT)(1:2) it showed a blue-shift. This indicates that the backbone chain is twisted due to the steric hinderance of the fluorophenyl group leading to shorter
-conjugation length. P(OT/FPT)(1:1) showed the highest EL intensity and the highest power efficiency among the three copolymers. In P(OT/FPT)(1:2) the roughness of the film surface causes unusually high local leakage current leading to the low efficiency of electroluminescence.
Study on Manufacturing and Characteristics of Silicone/EPDM Rubber Blend
Polymer Korea, volume 25, issue 3, 2001, Pages 406~413
Blending has become an interesting way for preparing new materials with tailored properties. Unfortunately, many materials are incompatible due to the difference in their viscoelastic properties, surface energy and interaction. Therefore, the properties of polymer blends are not obtained as expected levels. Silicone rubber has an excellent heat-resistance and electrical characteristics, and ethylene propylene diene monomer (EPDM) rubber also has good mechanical properties. The purpose of this study is to develop a new engineering material which has excellent electrical and mechanical properties through blending of silicone with EPDM rubber
Effect of Intercalant on the Synthesis and Properties of Epoxy Nanocomposites
Polymer Korea, volume 25, issue 3, 2001, Pages 414~420
In this study, the effect of type of intercalant on properties of epoxy nanocomposites was investigated. Cetyltrimethylammoniumbromide (CTMA) as an alkylammonium salt and cetyltributylphosphoniumbromgide (CTBP) as an alkylphosphonium salt were used to modify sodium montmorillonite. In the case of using the CTMA as an intercalant, the long spacing of the silicate layer was about
. When CTBP was used, the long spacing of the silicate layer (
) was higher than that of CTMA. From these results, the characteristic length of the modified silicate was found to be significantly affected by the type of intercalant. We also noted that the thermal stability of modified MMT were affected by the type of intercalant, but in the epoxy nanocomposites prepared from the modified MMT, the thermal stability remains almost the same regardless of the type of intercalant. Tensile strength and elongation of epoxy nanocomposites prepared from MMT modified with CTBT were found to be higher than those of the epoxy nanocomposite prepare with WT modified with CTMA.
Preparation of Exfoliated PCL/Clay Nanocomposite and Its Characterization
Polymer Korea, volume 25, issue 3, 2001, Pages 421~426
11-Aminododecanoic acid, to insert the functional group of -COOH reacted with the end group of poly(
-caprolactone) diol, and cetyltrimethylammonium bromide (CTMA), to increase the d-spacing of Montmorillonite (MMT), were intercalated into
MMT. The modified MMT was reacted with poly(
) diol (
) in THF solution at
for 4 hrs. After reaction, poly(
) was mixed into the solution for 12 hrs. To prepare the PCL/clay nanocomposite film this solution was cast into the silicon mold at
in vacuum oven for 6 hrs. From the results of XRD and TEM, it was found that the exfoliated PCL/clay nanocomposite were prepared. The effects of the amount of MMT on the mechanical properties and thermal properties of PCL/clay nanocomposites have been investigated by tensile tester and DSC. Because the MMT was dispersed homogeneously in PCL matrix, the Young's modulus of the nanocomposite were found to be excellent. However, MMT dispersed in PCL matrix had almost no effect on the tensile strength of the composites. The crystallization temperature of PCL increased in proportion to 3 wt% MMT in the PCL matrix.
A Study on the Characteristic of Sound Absorption of the Polyester Non-Woven Fabrics Used for the Automobile Sound Absorption Material
Polymer Korea, volume 25, issue 3, 2001, Pages 427~434
The sound absorption materials With polyester (PET) were prepared for automobile. They consist of 3 layers with different size of PET fiber (3 and 15 deniers) in order to optimize the characteristic of sound absorption, and with various densities (895~1790 g/
) by controlling the weight of PET of each layer. They were also compared with the commercial sound absorption materials made of glass wool. It was shown that the new PET had better absorption capability in both high and low frequency regions than that of the commercial material. It was revealed also that the density and the thickness of PET played an important role to determine the capability of sound absorption. The NRC (noise reduction coefficient) was increased by 22-39% with optimized PET sound absorption material. It should be noted that the PET can substitute the glass wool, a commercial sound absorption material, in view of environment and as well as recycle capability of sound absorption.
Influence of Oxidation Inhibitor on Carbon-Carbon Composites : 7. Studies on Work of Adhesion and Fracture Toughness of Carbon-Carbon Composites
Polymer Korea, volume 25, issue 3, 2001, Pages 435~440
The objective of this study was to examine the effect of oxidation inhibitor contents on the work of adhesion, fracture toughness, and impact strength of the unidirectional carbon-carbon composites (C/C composites). The molybdenum disilicide (
) used as an oxidation inhibitor was impregnated with phenolic resins to improve the anti-oxidation properties of the composites in different concentrations of 4, 12 and 20 wt%. Based on Wilhelmy equation, the work of adhesion of C/C composites was calculated by contact angle methods. Fracture toughness and impact strength were pressured by three-point bending test for the critical intensity factor (
) and Izod test method, respectively. As a result, the composites made with
resulted in an increasing of both fracture toughness and impact strength. Especially, the composites made with 12 wt%
content showed the highest value of London dispersive component,
, in work of adhesion, resulting from improving the interfacial adhesion force among fibers, filler, and matrix in this system.
A Study on the Compatibilization of Blends Based on Poly(phenylene ether) and Polyamide
Polymer Korea, volume 25, issue 3, 2001, Pages 441~449
Compatibilization of blends based on poly(phenylene ether) (PPE) and polyamide (PA) has been practiced with the incorporation of a copolymer formed by grafting polystyrene onto polybutadiene latex (g-BS) which is further functionalized with maleic anhydride (MAH) (g-BS*) to impart reactivity with amine groups of PA. The major focus has been placed on the effect of the various structural factors in g-BS8 on the phase morphology and mechanical performance of the blends. For the balance of impact strength and heat resistance, it was important to locate g-BS n particles inside of the PPE phase, which was accomplished by the proper control of the molecular weight and amount of PS in g-BS*. For g-BS*'s having constant molecular weight and amount of PS, the reduction of MAH content or increase of rubber particle size in g-BS* resulted in the increase of domain size and consequently loss in mechanical properties. Based on the comparison made with the conventional PPE/PA blend comprising MAH grafted PPE as a compatibilizer, it was confirmed that the comparable level of mechanical performance can be achieved by an appropriate g-BS* type material with improved whiteness index.