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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
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Synthesis and Their Properties of PP Graft Copolymers by E-beam Radiation and Vapor Phase Reaction
Polymer Korea, volume 26, issue 3, 2002, Pages 287~292
Graft copolymerization of styrene and glycidyl methacrylate (GMA) to the peroxidized polypropylene (PP) fabric with E-beam in
atmosphere was carried out in vapor phase with benzoyl peroxide (BPO) as an initiator. The degree of grafting of copolymers was increased with the increase of the reaction temperature and the highest degree of grafting was obtained at
with styrene, and at
with GMA. The highest degree of grafting of styrene grafted PP according to reaction time was higher than that of GMA grafted PP. In vapor phase graft polymerization, the degree of grafting of copolymers according to water composition in monomer mixture was effected by the boiling temperature of monomers.
Synthesis and Characterization of Polymers with the Moiety of m-Cresol as a Microbicide
Polymer Korea, volume 26, issue 3, 2002, Pages 293~299
By the reaction of m-cresol as a microbicide with acryloyl chloride m-cresyl acrylate (CA) was synthesized, and polymers with the moiety of m-cresol were prepared by the radical terpolymerization of CA -methylmethacrylate -acrylic acid. The contents of CA unit in the polymers were found to be 4.7 mol% and 10.1 mol% from their nuclear magnetic resonance spectra. The number -average molecular weights of the polymers were in the range of 12000 to 15000. Through the hydrolysis of the polymers m-cresol was released. The release rate of the microbicide increased with increasing PH of the release medium. This result can be attributed to enhanced proton dissociation of carboxyl group of the acrylic acid unit in the polymers. These polymers showed microbicidal activities for S. aureus as a positive microbe and E. coli as a negative microbe.
RGD Fixation of Film Surface and Synthesis of Copolymer Comprising Malic acid
Polymer Korea, volume 26, issue 3, 2002, Pages 300~306
To study the effect of polymer compositions on the cell adhesion, copolymers of 3-(S)-[(dodecyloxycarbonyl) methyl]-1,4-dioxane-2,5-dione (DMD) and L-lactide were made, where DMD was synthesized form L-malic acid (L-MA) and glycolic acid. Furthermore, the copolymerization of DMD and L-lactide was performed using tin(II) octanoate as a catalyst. As a result of fixing RGD on the copolymer films, the cell adhesive peptide was fixable on the surface of the film. It was found out that the amount of fixation of RGD also increases by the increase in the amount of MA unit introduction. Since it is gradually decomposed over a long period and neither remains nor accumulation occurs, glycolic acid-
-dodecylmalate -lactic acid (D-PGML) is greatly expected as a potential biomaterial with improved slow degradability.
Effect of Solvent Content on Morphology and Rubber Particle Size Distribution of High Impact Polystyrene
Polymer Korea, volume 26, issue 3, 2002, Pages 307~315
Major factors affecting the impact resistance of high impact polystyrene (HIPS), the rubber-toughened grade of polystyrene, are rubber-phase particle size and size distribution, molecular weight, morphology, and degree of grafting. Accordingly, it is important to control or investigate these factors. In this study, the effect of solvent content was analyzed by the morphology and particle size distribution of rubber phase, and final properties in bulk-solution polymerization of HIPS. The prepolymerization time was, first, determined by measuring the evolution of particle size distribution of dispersed phase to explain the phase inversion with time. As the solvent content increased, the size of rubber particle increased and then gradually decreased. Rubber-phase morphology was likely to have higher degree of grafting as the solvent content increased. Rheological and mechanical properties decreased as the solvent content increased because of the decrease of matrix molecular weight due to the chain transfer reaction to solvent and the existence of residual solvent. Nevertheless, the impact resistance seemed to increase when the rubber particle size increased.
Coalescence of Dispersed Phase for Immiscible Polymer Blends in Quiescent Flow Field
Polymer Korea, volume 26, issue 3, 2002, Pages 316~325
The deformation and coalescence behaviors of immiscible LDPE/PS blends (86.5/13.5 vol%) prepared by internal mixer were studied using rheometer and scanning electron microscope. The fine droplets coagulated at initial stage of mixing, and deformed fiber at large strain. The critical capillary number was calculated according to the empirical equation of De Bruijn and it was 0.95, the local capillary number was 3.867. The polymer blends were annealed at
for various time to investigate morphological change of polymer blends. The maximum size of droplet after annealing at
was found at
=1798, and there was destruction of the morphology at 15 minutes of annealing time. The viscosity of matrix was critical to determine a coalescence of droplet.
Preparation and Characterization of Biodegradable Poly(
-caprolactone) Microcapsules Containing Erythromycin by Emulsion Solvent Evaporation Technique
Polymer Korea, volume 26, issue 3, 2002, Pages 326~334
The purpose of this work was the producing of a biodegradable poly(
-caprolactone) (PCL) microcapsule and the analyzing of form and features for the manufacturing conditions which could be observed in a prospective drug delivery systems (DDS) through drug release. The effects of different stirring rates, stirring times and concentrations of emulsifier for the diameter and form of the microcapsules were observed using image analyzer (IA) and scanning electron microscopy (SEM). As a result, the microcapsules were made in wrinkle and spherical forms with a mean particle size of 40~300
. PCL microcapsules containing drugs were confirmed using FT-IR spectra. The role of interfacial adhesion between PCL and drug was determined by contact angle measurements. The drug release test of PCL microcapsules was characterized by UV/vis. spectra. It was found that the drug release rate of the microcapsules prepared with high concentration emulsifier was significantly fast.
A Study on Fabrication of Polyester Copolymers (Ⅵ) -Physical Properties of PET/PETG Copolymer Blend by the Drawing Conditions-
Polymer Korea, volume 26, issue 3, 2002, Pages 335~343
Blend resin (PET/PETG 70/30 blend) of poly (ethylene terephthalate) (PET) and poly (ethylene terephthalate glycol) (PETG) of weight percent 70/30 was prepared by a twin-screw extruder. Undrawn films of the blend and pure PETG were made by melt-press in hot press. Drawn films were made by capillary rheometer. Crystallinity, shrinkage, thermal, dynamic mechanical, and mechanical properties of these blends and PETG drawn films were investigated by wide angle X-ray diffractometer, dry oven, DSC thermal analyzer, and tensile tester. The crystallinity and density of these films increased with increasing draw ratio and draw rate but decreased with increasing draw temperature. The crystallinity and density of the blend films were higher than those of PETG films. The tensile strength and tensile modulus of these drawn alms increased with increasing draw ratio and draw rate but decreased with increasing draw temperature. The tensile strength and tensile modulus of blend films were higher than those of PETG films. Shrinkage of PETG md blend films decreased with draw ratio and draw rate. Shrinkage of undrawn blend film was 600% higher than that of pure PET film.
Thermal Properties and fracture Toughness of Difunctional Epoxy Resins Cured by Catalytic Initiators
Polymer Korea, volume 26, issue 3, 2002, Pages 344~352
In this work, two thermal cationic latent catalysts, i.e., triphenyl benzyl phosphonium hexafluoroantimonate (TBPH) and benzyl 2-methylpyrazinium hexafluoroantimonate (BMPH) were newly synthesized. And the thermal and mechanical properties of difunctional epoxy (diglycidylether of bisphenol h, DGEBA) resins initiated by 1 phr of either TBPH or BMPH catalyst were investigated. As experimental results, the epoxy/TBPH system showed higher curing temperature and critical stress intensity factor (
) than those of epoxy/BMPH. This could be interpreted in terms of slow thermal diffusion rate and bulk structure of four phenyl groups in TBPH. However, the decomposed activation energy determined from Coats-Redfern method was lower in the case of epoxy/TBPH. This result was probably due to the fact that broken short chain structure was developed by steric hindrance of TBPH.
Effect of High Intensity Ultrasonic Wave on the Degradation Characteristics of PEO
Polymer Korea, volume 26, issue 3, 2002, Pages 353~359
High intensity ultrasound has been applied to a series of poly(ethylene oxide) (PEO)/water systems having different molecular weights of PEO. Major interest was focused on the effect of ultrasonic wane on the melt viscosity chemical structure and thermal properties of PEO. The expected role of ultrasound used in this study was to generate macroradicals of PEO chains by the formation and subsequent collapse of bubbles. It was found that the melt viscosity and chemical structure of PEO change significantly depending on the sonication time. For the prolonged sonication, PEO chains were significantly degraded and new end groups were formed by the interplay of various radical species. When the molecular weight of PEO was relatively higher, the crystallization rate was decreased and the intensity of the melting peak was reduced.
The Effect of Processing Parameters on the Diameter of Electrospun Polyacrylonitrile(PAN) Nano Fibers
Polymer Korea, volume 26, issue 3, 2002, Pages 360~366
The electrospinning of polyacrylonitrile dissolved in N,N-dimethyl formamide (DMF) successfully produced nano-scale fibers. The processing parameters such as charged voltage, velocity of collected roller, and tip-to-collector distance (TCD) , affected the ultimate fiber size. At TCD of 5 cm, the average tiber diameter increased with increasing charged voltage because of the more aggregation between fibers due to the remaining DMF solvent on the fiber surface. But, at TCD of 9 cm, the average fiber diameter decreased as the charged voltage was increased because of complete evaporation of DMF. Also, the fiber diameter decreased with increasing the velocity of collected roller. Cross direction width (CWD) of nonwoven mat increased with decreasing the charged voltage and with increasing TCD.
PTCR Characteristics of Multifunctional Polymeric Nano Composites
Polymer Korea, volume 26, issue 3, 2002, Pages 367~374
Electrical characteristics of crystalline polymer composites filled with nano-sized carbon black particle were studied. The developed composite system exhibited a typical positive temperature coefficient resistance (PTCR) characteristic, where the electrical resistance sharply increased at a specific temperature. The PTCR effect was sometimes followed by a negative temperature coefficient resistance (NTCR) feature with temperature, which seemingly caused by the coagulation of nano-sized carbon black particles in the excessive quantity. The PTCR temperature was controlled by the carbon black content and the external voltage. The change of electric conductivity was shown as a function of carbon black content, and the resistance was constant when the carbon black content was over 20 wt%. The room-temperature resistance was maintained by a repeated heating and cooling. The excellent PTCR characteristic was demonstrated by the low resistance in the initial stage and the instantaneous heating capability.
A Study on the Preparation of the Exfoliated Polyimide Nanocomposite and Its Characterization
Polymer Korea, volume 26, issue 3, 2002, Pages 375~380
Diamines (p-phenylenediamine , m-phenylenediamine , and n-hexamethylenediamine) were intercalated into sodium montmorillonite for the further reaction with the anhydride end groups of polyamic acid. The anhydride terminated polyamic acid was synthesized using a mole ratio of 4,4'-oxydianilline : 1,2,4,5-benzene tetracarboxylic dianhydride = 1.50 : 1.53. The modified montmorillonite was reacted with polyamic acid terminated with anhydride group in N-methyl-2-pyrrolidone (polyamic acid/clay nanocomposite). After imidization, thin films of the polyimide/clay nanocomposite were prepared. From the results of XRD and TEM, we found that mono layered silicates were dispersed in polyimide matrix and those resultants were exfoliated nanocomposites. Mechanical properties of exfoliated polyimide nanocomposite were better than both those of pure polyimide and those of intercalated polyimide nanocomposite.
Polyurethane Nanocomposites with Organoclay
Polymer Korea, volume 26, issue 3, 2002, Pages 381~388
The properties of polyurethane (PU) nanocomposites with organoclay have been compared in terms of their thermo-mechanical properties, morphology, and gas permeability. Hexadecylamine-montmorillonite (
-MMT) was used as an organoclay to make PU hybrid films. The properties were investigated as a function of organoclay content (1-4 wt%) in the PU matrix. Transmission electron microscopy (TEM) photographs showed that most clay layers were dispersed homogeneously into the matrix polymer in nano-scale, although some particles of clay were agglomerated. We also found that the addition of only a small amount of organoclay was enough to improve the thermal stabilities and mechanical properties of PU hybrid films while gas permeability was reduced. Even at low organoclay content (<5 wt%), the PU nanocomposite showed much better thermo-mechanical properties, and lower gas permeability than pure PU.
Chemical Modification and Functionalisation of Poly(ethylene terephthalate) Fiber
Polymer Korea, volume 26, issue 3, 2002, Pages 389~399
Poly (ethylene terephthalate) (PET) fibers were modified by deep UV irradiation which was produced by a low pressure mercury lamp. FT-IR and XPS analyses were used to elucidate the surface chemical composition of PET fibers treated with UV. Relative
intensity increased considerably and it was found that oxygen was incorporated in the form of COO on the fiber surface. FT-IR and XPS analyses proved the existence of carboxylic groups on the surfaces and the adsorption test of cationic compound further supported these results. The concentration of carboxylic acid group on the surface increased remarkably with Increasing irradiation time. XPS analysis and adsorption experiments proved that the surface structure of the UV-irradiated PET fibers were stable for 12 months. Antibacterial property and the deodorization rate of UV-irradiated PET fibers adsorbed with the berberine compound were investigated. Reduction rates of bacteria increased by about 21 to 99% compared to unradiated PET fiber. Deodorization rates of 23% for unradiated PET fiber increased to about 75% for 30 min irradiated samples.s.
Preparation and Characterization of Polyurethane Microcapsules Containing Functional Oil
Polymer Korea, volume 26, issue 3, 2002, Pages 400~409
Polyurethane microcapsules containing functional oil (citronella oil) were successfully prepared by conventional interfacial polymerization of tolulene 2,4-diisocyanate (TDI) and ethylene glycol (EG) and characterized by Fourier transform (FT-IR) spectroscopy, Ultraviolet spectroscopy, particle size analysis, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Tile effects of polymerization variables, such as surfactant concentration and agitation speed, on the particle size and particle size distribution were investigated. FT-IR spectroscopic data showed that citronella oil was successfully encapsulated in the microcapsule. Thermogravimetric analysis data showed that the microcapsule was thermally stable up to
. The controlled release of the citronella oil present in the microcapsule core in a methanol medium was demonstrated by ultraviolet spectroscopy showing that the amount of released citronella oil was increased with increasing time. It was observed that the amount of released citronella oil was increased with increasing stirring speed and emulsifier concentration in the rnicrocapsule preparation step. Polyurethane microcapsules containing citronella oil showed excellent anti-moth property.
Glass Transition Temperature of Poly(methyl methacrylate) Obtained with Ferrocene-Based Diimine Pd(II) Catalyst
Polymer Korea, volume 26, issue 3, 2002, Pages 410~414
The late transition Pd catalyst of low oxophilicity that has ferrocene -based diimine ligand for stabilization of center metal had been synthesized and applied for the polymerization of methyl methacrylate (MMA). In the presence of triisobutylaluminium (TIBA) for impurity scavenger, the effects of polymerization temperature and [TIBA]/[Pd] mole ratio on the yield and glass transition temperature (
) of PMMA had been examined. For 40~
of polymerization temperature and 2000~3000 of [TIBA]/[Pd] mole ratio, higher polymer yields were obtained. It was observed that (
) of PMMA is almost independent to the polymerization temperature but influenced by the [TIBA]/[Pd] mole ratio. With the examination of(
) of PMMA with the structure of polymer, it had been found that T
of PMMA exhibits a linear relationship with the isotacticity of polymer.r.