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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 26, Issue 6 - Nov 2002
Volume 26, Issue 5 - Sep 2002
Volume 26, Issue 4 - Jul 2002
Volume 26, Issue 3 - May 2002
Volume 26, Issue 2 - Mar 2002
Volume 26, Issue 1 - Jan 2002
Selecting the target year
Synthesis of Sulfonated Hollow PP-g-Styrene Fibrous Ion-exchange Membrane and Separation of BSA Protein
Polymer Korea, volume 26, issue 4, 2002, Pages 415~421
A sulfonated PP-g-styrene ion-exchange hollow fiber membrane was prepared by pre-irradiation method with E-beam followed by sulfonation reaction. Degree of grafting increased with the increase of styrene monomer concentration and showed the maximum value of 128% at 80% of styrene monomer composition. Sulfonation yield increased with the degree of grafting. At 100% degree of grafting, sulfonation yield showed the maximum value of 13.4%. Ion exchange capacity of sulfonated HPP-g-styrene of 3.42 meq/g was attained, resulting in the remarkable increase of adsorption ability BET analysis proved that the surface area of sulfonated HPP-g-styrene was 62.54
and the mean pore size was 25
. From the BSA adsorption experiments, the adsorption amount of BSA was increased with sulfonation. At 13.4% sulfonation yield the adsorption amount of BSA was maximum as 3.8 mg/g. Sulfonated HPP-g-styrene was synthesized successfully and suitable for the adsorption and separation of BSA.
Kinetic Study on the Polycondensation Reaction of Bis-hydroxyethyl Naphthalate
Polymer Korea, volume 26, issue 4, 2002, Pages 422~430
The kinetics of polycondensation of bishydroxyethyl naphthalate has been studied in the range of 241 -
using antimony trioxide catalyst. The reaction was performed in a batch reactor and the concentration of reaction mixture was measured with HPLC. The activation energy values of forward and reverse reaction determined from molecular species model were found to be 19.7 and 31.4 kcal/mole, respectively, and the equilibrium constants were in the range of 1.4-2.0, which were larger than that of polycondensation of PET and varied to some degree with temperature. It was confirmed by applying the Flory's distribution function that the reaction rate of the hyroxyethyl group does not depend on the molecular size. By applying functional group model, we observed that there was few difference between the activation energy of the forward reaction and that of reverse reaction, therefore the equilibrium constant has almost constant value of 1.4. The rate constants obtained from functional group model was about 3-4 times larger than that from molecular species model, which showed that both model explains the reaction system well. Although the molecular species model should predict the concentration of as many as ten molecules, it fits for the experimental results well.
Thermal Stability of Polarized UV Exposed Polyimide Films for Liquid Crystal Display
Polymer Korea, volume 26, issue 4, 2002, Pages 431~438
We studied the orientation behavior and thermal stability of polyimide (PI) molecules under irradiation of polarized UV (PUV) using polarized fourier transform infrared (FTIR) spectroscopy. In the case of PUV-exposed PI films, the remaining PI molecules after photo-degradation showed molecular orientation perpendicular to the irradiated PUV polarization direction predominantly, due to the preferential degradation of PI molecules parallel to the irradiated PUV Polarization direction. On the other hand, the rubbing of PI films induced reorientation of the PI molecules parallel to the rubbing direction. We also investigated the thermal stability of the alignment layers furled by rubbing and PUV irradiation on the PI films using Polarized FTIR. The thermal stability of the PUV irradiated PI alignment layer is lower than that of the rubbed PI layer due to the fragmentation reaction of the PI by PUV.
Synthesis and Characterization of New Polyesters Having Unsaturated Groups from Bis [4-(alkyloxy)benzilidene]succinic Anhydride
Polymer Korea, volume 26, issue 4, 2002, Pages 439~444
Several monomeric benzilidene anhydrides (2a~d) haying n-alkyloxy groups with various n-alkyl chain lengths were prepared by Stobbe condensation of diethyl succinate with 4-(n-alkyloxy)benzaldehyde (1a,b) followed by hydrolysis by the succinates and cyclodehydration of the benzilidenated succinic acids. Configurational isomerism of the monomer was investigated by spectroscopic means. It was found that monomers (2a~d) exist in (Z,Z)-isomeric structure. Polymerization was carried out in bulk at 150~
range in nitrogen flow. The chemical structure and thermal properties of the polymers were characterized by spectroscopic means, TGA and DSC. Their properties highly depended on their chemical structures in accordance with a side chain length.
Filler-Elastomer Interactions 5. Effect of Silane Surface Treatment on Interfacial Adhesion of Silica/Rubber Composites
Polymer Korea, volume 26, issue 4, 2002, Pages 445~451
In this work, the adsorption characteristics and mechanical interfacial properties of treated silicas by silane coupling agents, such as,
-methacryloxy propyl trimethoxy silane (MPS),
-glycidoxy propyl trimethoxy silane (GPS), and
-mercapto propyl trimethoxy silane (MCPS), were investigated. The equilibrium spreading pressure (
), surface free energy (
s/), and specific surface area (
) were studied by the BET method with
/77 K adsorption. The developments of nonpolar functional groups of the silica surfaces treated by silane coupling agents led to the increase in the
, resulting in the improved tearing energy (
)of the silica/rubber composites. The composites treated by MPS showed the superior mechanical interfacial properties in these systems. These results explained by changing of crystalline size, dispersion, agglomerate, and surface functional group of silica/rubber composites.
Discoloration and the Effect of Antioxidants on Thermo-Oxidative Degradation of Polyamide 6
Polymer Korea, volume 26, issue 4, 2002, Pages 452~461
In this study, the effect of various concentrations of antioxidants on thermo-oxidative degradation of polyamide 6 was investigated. Unstabilized and stabilized polyamides 6 were subjected to long-term oven aging in ambient atmosphere at 70~
. All of specimens were discolored within 100 hr at temperature range of 70~
. Optimum antioxidant concentration was determined from the data of mechanical properties, yellowness index and relative viscosity. The synergistic effect of each primary and secondary antioxidant concentrations was not observed. Yellowing phenomenon was explained by using NMR, IR and EA. Different carbonyl groups were detected by
/NMR. During thermooxidative degradation, oxygen consumptions were determined by EA. The lifetime after long-term aging was predicted using Arrhenius equation.
Physical and Optical Properties of PMMA/PVDF Blends
Polymer Korea, volume 26, issue 4, 2002, Pages 462~467
Blends of polymethylmethacrylate (PMMA) with polyvinylidenefluoride (PVDF) were prepared by melt mixing and investigated for optical waveguide devices by using hot embossing process. The glass transition temperatures (
) of the blends were decreased with increasing PVDF contents. However, the crystalline of PMMA/PVDF blends was not appeared by DSC and XRD due to miscibility between PMMA and PVDF. Shear viscosities and refractive indices of the blends were decreased with increasing PVDF contents. Optical transmittances and absorption losses of the blends were improved with increasing PVDF contents. This is due to a decreasing of polarizability of molecules by fluorine molecule in the PVDF.
A Study on Elongation/Contraction Behavior and Mechanical Properties of Oxy-Polyacrylonitrile(PAN) Fiber in Basic/Acidic Solution for Artificial Muscle Applications
Polymer Korea, volume 26, issue 4, 2002, Pages 468~476
Oxy-PAN fiber prepared from the preoxidation and saponification of raw PAN fiber is known to elongate and contract when immersed in basic and acidic solutions, respectively. In this study, about 30% elongation in NaOH solution and 30∼50% contraction in HCl solution have been observed. In mechanical test, the mechanical properties of oxy-PAN fiber in the contracted state was stronger than that in the elongated state. These behaviors and mechanical properties are compared to those of living muscle and linear actuator. The change of length in NaOH and HCl solutions is due to switching between a hydrophilic and a hydrophobic structure. Other reasons are exchange of ion and water in/out of oxy-PAN fiber, and osmotic pressure difference associated with relevant ions. Much studies are needed to clarify the effective factors on but the oxy-PAN fiber's elongation/contraction behavior and mechanical properties, but the oxy-PAN fiber perpared in our laboratory has a sufficient potential for application as artificial muscle and linear actuator.
Effect of KOH Addition on Pore Structure of Glassy Carbon Prepared by Polymerization of Phenolic Resin
Polymer Korea, volume 26, issue 4, 2002, Pages 477~482
In order to control the micro-pore structure of glassy carbon (GC), an activation agent of KOH was introduced as the glassy carbon was prepared from phenolic resin with a curing agent of phosphoric acid. The yield and properties of GC were investigated as a function of KOH content. Although the GC produced without KOH had nonporous structure except the trace of bubble formation, the GC with KOH had very porous structure. The surface area of GC with KOH increased continuously up to 870
/g with the increase of KOH content. The carbonization yield and apparent density measured in water reduced from 40 to 15% and iron 1.5 to 0.9 g/
, respectively, and the electrical resistivity increased from
.cm with the increase of KOH content.
A Study on the Tensile Properties and Impact Behavior of Polyurethane/Nylon 6 Melt Blends
Polymer Korea, volume 26, issue 4, 2002, Pages 483~491
Polyurethane (PU)/nylon 6 blends were prepared by melt blending with Haake Rheomix at
. The compositions of PU/nylon 6 blends were 10/90, 20/80, 30/70, 40/60, and 50/50 (wt%). The effects of PU contents and blending time on the crystal structure, tan
, the tensile properties, and the impact behavior were investigated by means of WAXD and DMA, etc. The crystalline diffraction peaks are broadened, and their intensities are reduced with increasing PU contents and blending time. The glass transition temperature, the tensile strength, and the tensile modulus of the blends are also decreased and the elongation at break is increased. The influence of PU content on the crystal structure, tan 3, and the tensile properties of PU/nylon 6 blends is more significant than that of blending time. The impact strength of PU/nylon 6 (10/90 wt%) blends measured at 20 and
could be greatly improved.
Morphological Behavior of Oxy-PAN Fiber upon pH Variation
Polymer Korea, volume 26, issue 4, 2002, Pages 492~500
Oxidized-polyacrylonitrile (oxy-PAN) was prepared by oxidation of PAN fiber at
, followed by base catalyzed hydrolysis reaction. The chemical structure of PAN fiber in various pH conditions was characterized by
spectroscopy. The characteristic contraction and expansion behavior of oxy -PAN fiber was observed in acidic and basic medium, respectively. In basic condition, water molecules might be absorbed into the fiber with the movement of charge balancing
ion, on the other hand, the water molecules seemed to be expelled in acidic condition to result in contraction. It was also observed that the facile chemical modification occurred due to free diffusion of aqueous reagent into the hydrophilic PAN fiber, and the morphology was affected by pH condition.
Synthesis and Cure Behaviors of Diglycidylether of Bisphenol-S Epoxy Resins
Polymer Korea, volume 26, issue 4, 2002, Pages 501~507
In this work, diglycidylether of bisphenol-S (DGEBS) epoxy resin was prepared by alkaline condensation of bisphenol-S (BPS) with epichlorohydrin (ECH) in the presence of NaOH catalyst. The structure of the synthesized DGEBS epoxy resin was confirmed by IR, NMR spectra, and elemental analysis. The curing reaction and glass transition temperature (
) of DGEBS epoxy resin cured with phthalic anhydride (PA) and tetrahydrophthalic anhydride (THPA) at curing agents were studied by dynamic differential scanning calorimetry (DSC). The thermal stability of the cured specimen was investigated by thermogravimetric analysis (TGA). As a result, the activation energy (
) of DGEBS/PA system was higher than that of DGEBS/THPA system, whereas
, initial decomposed temperature (IDT), and decomposition activation energy (
) of DGEBS/PA were lower than those of DGEBS/THPA. This was probably due to the fact that the crosslinking density of DGEBS/THPA was increased by ring strain of curing agent.
Effects of Irradiation Crosslinking and Molecular Weight Properties on Crosslinked PP Foaming Process
Polymer Korea, volume 26, issue 4, 2002, Pages 508~515
The effects of the crosslinking caused by irradiation dose, molecular weights of the foaming materials, and various foaming processes on the foam structure of the polypropylene (PP) were investigated. The maximum gel content of the PP was 48% when the sheet was irradiated with 3.2 Mrad. This high gel content improved the cell structures by providing high thermal stability. The increase of both the gel content and structural development were stopped at the irradiation dose exceeding 3.2 Mrad. The increase of the molecular weights served to help produce a foam with particularly fine and even cell structures, along with improved thermal stability as well.
Studies on the Adsorption of Linear Alkylbenzene Sulfonate from Waste Water by Fibrous Aminated Acrylic ion-Exchanger
Polymer Korea, volume 26, issue 4, 2002, Pages 516~522
The ion exchange characteristic of quaternary ammonium as functional group containing aminated acrylic fibrous ion exchanger were studied for the adsorption of linear alkylbenzene sulfonate (LAS) in a continuous ion exchange process. The adsorption capacities of aminated acrylic for LAS as the adsorption temperature were increased with increasing adsorption temperature and were equilibrated at
. The maximum adsorption capacities as column packing ratio (L/D) were obtained at L/D>2. The adsorption capacity for LAS was increased with increasing pH and the maximum adsorption capacity as pH was obtained at pH 7. The effects of temperature and pH were similar to those of flow rate and concentration of LAS tin the breakthrough curves, the breakthrough time and slope of breakthrough corves decreased with increasing flow rate and concentration of LAS in adsorption process.
Optical and Swelling Properties of Photocrosslinked Cholesteric Gels Based on Acrylic Acid Esters of Hydroxypropyl Cellulose
Polymer Korea, volume 26, issue 4, 2002, Pages 523~534
A new hydroxypropylcellulose (HPC) capable of exhibiting reflection colours in the temperature ranges of about 60-
and acrylic acid esters of HPC (ESs) with degree of esterification (DE) ranging from 1 to 3 were synthesized. The crosslinked ES films with the optical pitch (
) ranging throughout the visible region were also prepared by exposing thermotropic cholesteric phases of ESs with a DE of more than 2 to UV light at
. The thermal and optical properties for both the uncrosslinked and crosslinked samples and the swelling behavior of the crosslinked films in acetone were investigated. The
's of ESs, as well as HPC itself, increased with temperature. However, the
's of ESs were larger than of HPC at the same temperature and decreased with increasing DE. The temperature dependence of
of the crosslinked samples was much weaker than that of ESs. Moreover, in contrast with ESs that exhibit a decrease of the isotropization temperature with increase in the DE, the networks were found to decompose at about
, giving no transition to an isotropic state. The crosslinked samples exhibited an anisotropic swelling, suggesting that the two-dimensional crosslinking preferentially performs between ES molecules.
Norfloxacin Release from Surfactant-Free Nanoparticles of Poly(DL-lactide-co-glycolide) and Biodegradation
Polymer Korea, volume 26, issue 4, 2002, Pages 535~542
We have prepared the surfactant-free nanoparticles of poly(DL-lactide-co-glycolide) (PLGA) by dialysis method and their physicochemical properties such as particle size and drug contents were investigated against various solvent. The size of PLGA nanoparticles prepared by using dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethylsulfoxide (DMSO) was smaller than that from acetone. Also, the order of drug contents was DMAc>DMF>DMSO=acetone. These phenomena could be expected from the fact that solvent affects the size of nanoparticles and drug contents. The PLGA nanoparticles have a good spherical shapes as observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Also, surfactant-free nanoparticles entrapping norfloxacin (NFx) have a good drug loading capacity without free-drug on the surface of nanoparticles confirmed by the analysis of X-ray powder diffraction. Release kinetics of NFx used as a model drug was governed not only by drug contents but also by particle size. Also, the biodegradation rate of PLGA nanoparticles prepared from DMF was faster than that prepared from acetone, indicating that the biodegradation of PLGA nanoparticles is size-dependent.
Studies on the Characteristics of Single-Layered Organic EL Device Using a Copolymer Having Hole and Electron Transporting Moieties
Polymer Korea, volume 26, issue 4, 2002, Pages 543~550
We have synthesized a novel carrier transporting copolymer having triphenylamine moiety as a hole transporting unit and triazine moiety as an electron transporting unit in the polymer side chain. Single-layered organic electroluminescent (EL) devices consisted of ITO/copolymer and emitting materials (DCM, coumarin 6, DPvBi)/Al exhibited maximum external quantum efficiency when the ratio of hole transporting unit and electron transporting unit is 6:4 and the content of emitting material is 30 wt%. Especially, the devices emitted the light of red (620 nm), green (520 nm) and blue (450 nm) corresponding to the emitting materials, respectively. A maximum luminance of ITO/copolymer (6:4) and DCM (30 wt%)/Al EL device was about 500 cd/
at a DC drive voltage of 12V.