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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 27, Issue 6 - Nov 2003
Volume 27, Issue 5 - Sep 2003
Volume 27, Issue 4 - Jul 2003
Volume 27, Issue 3 - May 2003
Volume 27, Issue 2 - Mar 2003
Volume 27, Issue 1 - Jan 2003
Selecting the target year
Interaction of Bone Marrow Stromal Stem Cells with Adhesive Protein and Polypeptide-adsorbed Poly(lactide-co-glycolide) Scaffolds
Polymer Korea, volume 27, issue 5, 2003, Pages 397~404
The interaction of cell adhesive protein and polypeptide with bone marrow stromal stem cells (BMSCs) grown in tissue engineered films and scaffolds were examined. Several proteins or polypeptide known as cell-adhesive were coated adsorption on poly(lactide-co-glycolide) (PLGA) films and scaffolds and adhesion and proliferation behavior of BMSC on those surfaces were compared. The protein and polypeptide used include collagen IV, fibrinogen, laminin, gelatin, fibronectin, and poly(L-lysine). The protein and polypeptide were adsorbed on the PLGA film surfaces with almost monolayer coverage except poly(L-lysine). BMSCs were cultured for 1, 2, and 4 days on the protein- or polypeptide-adsorbed PLGA films and scaffolds. The cell adhesion and proliferation behaviors were assessed by sulforho damine B assay. It was observed that the protein- or polypeptide-adsorbed surfaces showed better cell adhesion and proliferation than the control.
Preparation and Characterization of the Blends of Poly(vinyl alcohol) and N-(2-hydroxy)propyl-3-trimethylammonium Chitosan Chloride
Polymer Korea, volume 27, issue 5, 2003, Pages 405~412
Poly(vinyl alcohol) (PVA) and N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (HTCC), a water soluble chitosan derivative synthesized by the reaction of quaternary ammonium compound with chitosan, were blended using water as a solvent and the PVA/HTCC blend films with various compositions were prepared by solution casting method. The miscibility between the two polymers and the thermal properties of the blend films were investigated using FT-IR, DSC, DMA, and TGA. Single glass transition temperatures and single melting temperatures of the blend films along with the strong and clear film state for the whole composition of blending ratios suggest the miscibility between PVA and HTCC. The PVA/HTCC blend films with HTCC content of 1% and greater showed excellent antimicrobial activity.
Shear Induced Homogenization Study of an Immiscible Polymer Blend Solution Using Fluorescence Microscope
Polymer Korea, volume 27, issue 5, 2003, Pages 413~420
Fluorescence microscope technique was employed for the characterization of phase separation behavior of a 4-chloro-7-nitrobenzofurazan labeled polystyrene (PS) / polybutadiene (PB) blend in dioctyl phthalate under steady shear. It was confirmed that the fluorescence microscope images reflect the real phase morphology by comparing with the images of phase contrast microscope. Comparing the fluorescence intensities from the phase separated domain (PS rich) and continuous phase (PB rich), the composition difference between these two phases were deduced. The observed shear dependence of compositional change is then used to confirm that the phase diagram is indeed shifted under the steady shear.
Photopolymerization of Reactive Oligomers and Methacrylate/SBS Blends
Polymer Korea, volume 27, issue 5, 2003, Pages 421~428
The kinetics of photoinitiated polymerization of reactive oligomer methacrylates and oligomer methacrylate/SBS blends have been studied to characterize the diffusion-controlled reaction using Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (ATR-FTIR). The polymerization rates of reactive oligomer methacrylates and oligomer methacrylate/SBS blends were autocatalytic in nature at the initial stage and then a retardation of the reaction conversion occurred gradually as the polymer matrix became vitrified, and finally the reaction became diffusion controlled. Photopolymerization behavior of methacrylate/SBS blends was well predicted using the diffusion-controlled reaction model. N-Vinyl-2-pyrrolidinone (NVP) as a reactive solvent was used to incorporate SBS into methacrylate to form semi-IPN via photopolymerization. Due to the high reactivity of NVP, polymerization rate increased with the increase of NVP content. As the content of NVP-SBS in the blends increased up to 10 phr, the reaction conversion maintained almost constant. But above 20 phr of NVP-SBS in the blends, the reaction conversion gradually decreased since the increase of viscosity affected on the photopolymerization rate. The semi-IPN films of methacrylate/SBS blends were transparent at room temperature as well as at increased temperature and were able to be applied to surface coating.
Vinyl Addition Copolymerization of Norbornene/5-Vinyl-2-norbornene with Cationic
-Allyl Palladium Catalyst and Their Post-Reaction
Polymer Korea, volume 27, issue 5, 2003, Pages 429~435
Vinyl addition copolymerizations of norbornene (NB) and 5-vinyl-2-norbomene (VNB) were carried out using a cationic η
-allyl palladium catalyst in the various mole ratio of comonomers. The copolymers could be obtained in good yield (65∼85%) with high weight-average molecular weights (M
> 760,000). Depending on increasing VNB contents, the molecular weight and yield of the copolymers decreased. FT-IR analysis confirmed that actual contents of VNB in polymer were proportional to the feeding content of VNB. From
H-NMR spectroscopy, we found that both exo and endo VNB isomer were copolymerized with NB. Thermal stabilities of NB-VNB copolymers were independent on the VNB content and their initial decomposition temperatures were about 300 C. The NB-VNB copolymers were followed by epoxidation by using m-CPBA and hydroxylation by 9-BBN, respectively, and these post-polymers were characterized by FT-IR spectroscopy and
Characteristics of Thermoplastic Vulcanizate Weatherstrip Prepared by Water-Foaming Technique
Polymer Korea, volume 27, issue 5, 2003, Pages 436~442
Thermosetting elastomer such as EPDM (Ethylene Propylene Dien Rubber) has been applied to the sponge weatherstrip of a vehicle as a main material. However, the thermosetting elastomers have limited recycling and have brought about the environmental problems. Furthermore, many steps of the manufacturing process such as formulation, mastication and vulcanization make difficult to control uniformity of the endproducts. These problems of current EPDM weatherstrip necessitated development of a new recyclable material, Thermoplastic Vulcanizates (TPV). In this study the influence of the water contents, and the processing conditions. On the foam density and structure in water blowing process was carried out. We found that TPV also can be foamed with water, maintaining the uniformity form this study. Therefore, many inevitable problems of EPDM weatherstrip can be solved, and this new technique is expected to take a roll of making a breakthrough in the rubber industry.
Synthesis and Characterization of Polymers with the Moiety of 2-Phenylphenol as a Microbicide
Polymer Korea, volume 27, issue 5, 2003, Pages 443~448
2-Biphenylyl acrylate (BPA) was synthesized by the reaction of 2-phenylphenol as a microbicide with acryloyl chloride, and copolymers with the moiety of 2-phenylphenol were prepared by the radical terpolymerization of BPA-methylmethacrylate-acrylic acid. The contents of BPA unit in the poly mers were found to be 4.2 mol% and 9.1 mol% from their nuclear magnetic resonance spectra. The number average molecular weights of the polymers were in the range of 15000 to 16000. 2-Phenylphenol was released through the hydrolysis of the polymers. The release rate of the microbicide increased with increasing pH of the release medium. The released solution showed higher microbicidal activity for E. coli as a negative microbe than S. aureus as a positive microbe.
Preparation and Characterization of Biodegradable Poly(
-caprolactone)/ Poly(ethylene oxide) Microcapsules Containing Erythromycin
Polymer Korea, volume 27, issue 5, 2003, Pages 449~457
The purposes of this work were the producing of a biodegradable poly(
-caprolactone) (PCL) / poly(ethylene oxide) (PEO) microcapsule and the analyzing of form and features for the manufacturing conditions which could be observed in a prospective drug delivery systems through drug release. The effects of emulsifier, emulsifier concentration, and stirring rate for the diameter and form of the microcapsules were observed using image analyzer and scanning electron microscope. The role of interfacial adhesion between PCL/PEO and drug was determined by contact angle measurements, and the drug release test of the microcapsules was characterized by UV/vis. spectra. As a result, the microcapsules were made in spherical fonns with a mean particle size of 170 nm∼68
m. And the work of adhesion between water and PCL/PEO increased with increasing the content of PEO, probably due to the increased the hydrophilicity. It was also found that the drug release rate from the microcapsules significantly increased with increasing the content of PEO, which could be also attributed to the increasing of the hydrophilic groups or the degree of adhesion force at interfaces.
Effects of Dispersivity of Clay on Thermal Stabilities of PP/Clay Nanocomposites
Polymer Korea, volume 27, issue 5, 2003, Pages 458~463
The effect of ozone surface treatment of montmorillonite (MMT) was investigated in thermal stabilities of polypropylene (PP) nanocomposites. Sodium montmorillonite (Na
+/-MMT) was organically modified with dodecylammonium chloride. The surface properties of MMT, including the specific surface area (S
BET/), equilibrium spreading pressure (
e/), and London dispersive component (
L/), were studied by the BET method with
adsorption. Also, the thermal stabilities of the nanocomposites were investigated in DSC and TGA. As experimental results,
L/ of the ozonized dodecylammonium chloride (DA-MK (
)) were increased in about 1.7 and 3.5 mJ/
, resulting from the increasing of the micropores. From the DSC results, it was found that the melting temperature and crystallization temperature of PP/DA-MK and PP/DA-MK (
) were higher that those of pure PP. These results were explained that dodecylammonium chloride of nano-scale led to a nucleation effect for PP crystallization. Also, it was found that E
t/ of the PP/DA-MK (
) nanocomposies was increased within about 64 kJ/mol. These results were probably explained by the improvement of dispersivity of DA-MK (
) in a PP matrix.
Influence of Surface Treatment of SiO
and Stirring Rate on Fragrant Oil Release Behavior of Poly(
Polymer Korea, volume 27, issue 5, 2003, Pages 464~469
In this work, the fragrant oil release behavior of poly(
-caprolactone) (PCL) microcapsules containing SiO
was investigated. The SiO
was chemically treated in 10, 20, and 30 wt% hydrochloric acid and sodium hydroxide. The acid and base values were determined by Boehm's titration technique and
/77 K adsorption isotherm characteristics, the specific surface area and total pore volume were studied by BET. The PCL microcapsules containing SiO
and fragrant oil were prepared by oil-in-water (o/w) emulsion solvent evaporation method. The shape and surface of PCL microcapsules were observed using image analyzer and scanning electron microscope (SEM). The fragrant oil release behavior of PCL microcapsules was characterized using UV/vis. spectra. The average diameters of PCL microcapsules were decreased from 35 to 21
m with increasing stirring rate. It was found that in the case of acidic treatment the fragrant oil adsorption capacity and release rate were increased due to the increase of specific surface area and acid value. In the case of basic treatment, the fragrant oil adsorption capacity and release rate were decreased due to the decrease of sp ecific surface area and the increase of acid-base interactions between SiO
-NaOH and fragrant oil with increasing base value of SiO
Synthesis and Characterization of Novel Polythiourethanes
Polymer Korea, volume 27, issue 5, 2003, Pages 470~476
In order to obtain high refractive plastic materials, 1,2 -ethylenedisulfanylbis(2-mercaptomethyl-1-ethanthiol) (ESTT) was newly prepared in good yield by the reaction of 1,2-ethylenedisulfanylbis(2-bromomethyl-1-ethanthiol) (ESTB) with thiourea followed by hydrolysis using an aqueous ammonia solution and characterized by
H-NMR (-SH at 1.7 ppm),
SH at 28.4 ppm) and FT-IR (-SH at 2540 cm
-1/) spectroscopy, etc. Polythiourethanes (PTU) were obtained from the combinations of ESTT with each of 4,4＇-methylenebis(phenylisocyanate) (MDI), tolyene 2,4-diisocyanate (TDI), isophorone diisocyanate (IPDI), mxylene diisocyanate (XDI), and 1,6-diisocyanatohexane (HMDI) in the presence of dibutyltin dilaurylate as a catalyst, in a casting mold, and characterized by FT-IR (existence of N=C=O) spectroscopy and elemental analyzer (sulfur content). Accordingly, their thermal, mechanical and optical properties were investigated by using DSC, TGA, hardness tester and refractometer: both the melting point on DSC and crystallinity on X -ray diffraction (XRD) for specimens of PTUs were not observed. PTUs with T
g/s above 110
showed good hardness (Shore D) in the range of 86 to 89. Thermal stabilities of PTUs obtained by using ESTT and each of diisocyanates containing aromatic rings were especially good. Also, the optical transmittances of amorphous PTUs through UV-visible source in the range of 400 to 600 nm were good. PTUs showed refractive indexes above 1.60, and their refractive indexes gradually increased with increase of sulfur contents.
Structure Development in Drawn Poly(trimethylene terephthalate)
Polymer Korea, volume 27, issue 5, 2003, Pages 477~483
The structure development of drawn poly(trimethylene terephthalate) PTT as a function of draw down ratio and drawing temperature was studied. The special effort was made to find out the effect of structural development on thermal properties and crystallinity in drawn PTT. The changes in shrinkage ratio and mechanical properties were understood base on the level of crystallinity and orientation of the drawn PTT. The stress induced crystallization caused the increase in glass transition temperature and the decrease in cold crystallization temperature and enthalpy. The crystallinity and orientation were dependent upon the level of applied stress level as well as chain flexibility at high drawing temperature. The drawing resulted in the increase of shrinkage ratio but it was minimized by increasing of crystallinity. The development of orientation resulted in increasing modulus and tensile strength while decreasing elongation at break.
Characteristics and Stability of Liquid Crystal Alignment for Interfacial Properties of Polyimide-Liquid Crystal
Polymer Korea, volume 27, issue 5, 2003, Pages 484~492
How the characteristics and stability of the rubbing-induced alignment of nematic liquid crystals (LCs) relate to the interfacial characteristics of LC-polyimide has been studied. The characteristics of the LC alignment (such as the LC texture, the pretilt angle, and the anchoring energy) and their thermal stability have been investigated for 5 polyimides synthesized for this work. The work showed that the rubbed polyimide alignment layer induces the strong LC anchoring and that the characteristics and stability of LC alignment are determined by the short-ranged interactions between LC and polyimide molecules at the alignment layer surface. The increased flexibility of the polyimide accelerates thermal imidization, increases the pretilt angle, and improves the alignment stability. It also turned out that fluorination of the polyimide tends to deteriorate the alignment uniformity and stability. No distinct differences in the alignment characteristics were shown for the aromatic- and alicyclic-dianhydride polyimides.
Mechanical Properties of Denture Base Resin through Controlling of Particle Size and Molecular Weight of PMMA
Polymer Korea, volume 27, issue 5, 2003, Pages 493~501
Poly(methyl methacrylate) (PMMA) particles, denture base resin, were synthesized by suspension polymerization through control of polymerization conditions (stabilizer concentration, co-monomer concentration, and the agitation speed) and evaluated changes in molecular weight and particle size. We also investigated their mechanical properties of compression-molded samples which were from synthesized polymer powder mixed with methyl methacrylate (MMA) solution. under the condition of volumetric ratio as 2:1(PMMA powder and MMA solution). The results shows that the mechanical properties were mainly affected by particle size over 100
m (in particle size) and by molecular weight under 100
m (in particle size). From these results, we concluded that the most appropriate particle size of PMMA powder for heat-cured denture base resins is around 100
m. and its molecular weight is around 300000 (M
Thermal Behavior and Physical Properties of Low Density Polyethylene/Metallocene Linear Low Density Polyethylene Blends
Polymer Korea, volume 27, issue 5, 2003, Pages 502~507
The thermal and physical properties of low density polyethylene melt-blended with Metallocene linear low density polyethylenes were investigated. Since the Metallocene polyethylenes have similar MW and MWD except m-LLDPE4, it can be said that the thermal behavior and mechanical properties of the blends depend upon the l-octene comonomer content. The melting behavior of LDPE/m-LLDPE1 blends shows two melting peaks with LDPE contents higher than 50%, while the other blends show only one melting peak. It was observed that the blends show higher crystallization temperature and higher crystallinity with lower comonomer content. Initial modulus of a blend exhibited the behavior proportional to the crystallinity and the elongation at break of the blends was increased with increasing the m-LLDPE composition. Melt indices of the blends decreased with increasing the comonomer content of Metallocene LLDPE. Melt Index values of the blends show negative deviation.