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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 30, Issue 6 - Nov 2006
Volume 30, Issue 5 - Sep 2006
Volume 30, Issue 4 - Jul 2006
Volume 30, Issue 3 - May 2006
Volume 30, Issue 2 - Mar 2006
Volume 30, Issue 1 - Jan 2006
Selecting the target year
Synthesis of Novel Aromatic Polyimides
Shin Gyo-Jic ; Chi Jun-Ho ; Zin Wang-Cheol ; Chang Tai-Hyun ; Ree Moon-Hor ; Jung Jin-Chul ;
Polymer Korea, volume 30, issue 2, 2006, Pages 97~107
In spite of excellent thermomechanical performance the majority of aromatic polyimides are so poor in processability due to their high backbone rigidity that their applications are greatly limited. The introduction of long side chains not only enhances their processiblity but also makes useful contribution to discovering new application fields. In this article, a variety of novel aromatic polyimides with flexible side chains were prepared either from new dimines or new dianhydrides to measure the influence of the side chains on structure and properties of the polymers and their new applications as liquid crystal alignment layers, photosensitive polymers, alternating multilayer nano-films and photoluminescent materials are discussed.
Morphology of Membrane of Acrylic Polymers by Wet Phase Inversion Method
Choi Seung-Eun ; Park Han-Soo ; Lee Kwang-Hee ;
Polymer Korea, volume 30, issue 2, 2006, Pages 108~111
In this work, the effect of the hydrophobicity of acrylic polymers on the membrane morphology was investigated. The membranes were prepared with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly (butyl methacrylate) (PBMA), poly(isobutyl methacrylate), and their blends using the wet phase inversion method. PMMA and PEMA having a relatively less hydrophobicity formed the channel-like structure, whereas PBMA and PIBMA having more hydrophobic units formed the finger-like structure. These morphological changes were attributed to differences in the solidification process of the polymer-rich phase determine d by the polymer/solvent/nonsolvent ternary phase diagram. The membrane structures of the blends were controlled by the main component of their blends.
The Effects of Osmogant and Binder in Membrane on Nifedipine Release from Osmotic Granule
Jeong Sung-Chan ; Cho Young-Ho ; Kim Moon-Suk ; Lee Bong ; Khang Gil-Son ; Rhee John-M. ; Lee Hai-Bang ;
Polymer Korea, volume 30, issue 2, 2006, Pages 112~117
To improve the type error of osmotic tablet which is one of the drug delivery system, osmotic granule could be manufactured by fluidized bed coating. It has drug layer containing different amount of osmogant and is coated with membrane including different types of binder. We confirmed that the morphology of osmotic granule was different at each coating step. The more mont of osmotic agent, the faster drug release was observed due to increasing the driving force for drug release from osmotic granule. And drug release from osmotic granule coated with membrane using different types of binder was differed by solubility of binders to water. The formation of pore in membrane was confirmed by SEM and DSC Membrane using water soluble binder released more amount of drug. From these results, we assured that difference of osmotic pressure between the inside and the outside of granule and porosity of membrane have an effect on drug release from osmotic granule.
Effect of Transesterification on the Physical Properties of Poly(butylene terephthalate)/Poly(ethylene terephthalate) Blends
Kim Hoy-Kap ; Kim Jun-Kung ; Lim Soon-Ho ; Lee Kun-Wong ; Park Min ; Kang Ho-Jong ;
Polymer Korea, volume 30, issue 2, 2006, Pages 118~123
The effect of transesterification on the rheological properties in the melt reactive blending of poly(butylene terephthalate)(PBT) with poly(ethylene terephthalate)(PET) has been studied. The melt viscosity depression in PBT was found in PBT/PET blends due to the intrinsic low melt viscosity of PET compared to PBT. In addition, the thermal degradation in the melt blending and transesterification between two polyesters were considered as other factors fer the lowering of the melt viscosity in the blends. In the PBT/PET blends, calcium stearate was less effective than in PBT as a lubricant, however it accelerated both the thermal degradation and transesterification during melt blending. As a result, further melt viscosity drop was obtained in the reactive melt blending of PBT/PET.
Preparation and Characterization of Low Infrared Emissivity Bicomponent Fibers with Radar Absorbing Property
Yu Bin ; Qi Lu ;
Polymer Korea, volume 30, issue 2, 2006, Pages 124~128
Heavy weight of the camouflage materials was always the main problem. To solve it, the low infrared emissivity fibers with the radar absorbing property (LIFR) were prepared. The low infrared emissivity fibers (LIF) were firstly melt-spun by co-extrusion of polypropylene (PP) and PP/various fillers master-batches using general conjugate spinning. The infrared emissivity of LW with AA and ZnO was decreased respectively compared with that of pure polypropylene fibers. The infrared emissivity of LIF with 15 wt% Al and 2 wt% ZnO in the sheath-part can reach 0.58. To improve LIF radar absorbing property, LIFR was prepared by filling the 50 wt% ferrite and bronze in the core-part of LIF. The radar absorbing efficacy of LIFR was good and the infrared emissivity was low. For the characterization, fiber electron intensity instrument and differential scanning calorimetry (DSC) were used for the analysis of mechanical properties, thermal and crystallization behavior of the spun-fibers. Scanning electron microscopy (SEM) was carried out to observe the particle distribution of the bicomponent fibers.
Preparation of Urethane Nanocomposites with Inorganic Nano Fillers and Their Physical Properties
Yang Yun-Kyu ; Hwang Taek-Sung ; Hwang Eui-Hwan ;
Polymer Korea, volume 30, issue 2, 2006, Pages 129~134
Nanocomposites of polyurethane were prepared from inorganic nano particles,
, and surface modified MMT and their properties were investigated. It was shown that the molecular weight and polydispenity of nanocomposites of polyurethane were 20000 to 28000 and 1.0 to 2.0, respectively. d-Spacing for nanocomposites of MMT were increased than that of pure MMT. Initial degradation temperature of nanocomposites were 250 to
. And also, the range of weight loss for nanocomposites were decreased and the end of thermal degradation was observed at higher temperatures about
. The elongation at break for
filled nanocomposites were the highest among the nanocomposites used in this study. studied. It was found that the tensile strength increased with increasing the filler contents while the silica nanocomposite exhibited the lowest increase and the
nanocomposite the highest.
Dental Properties of Hydroxyapatite Filled Polymer Composite
Kim Oh-Young ; Seo Ki-Taek ;
Polymer Korea, volume 30, issue 2, 2006, Pages 135~139
To evaluate the dental restorative application of polymer composites filled with hydroxyapatite (HAP) which is an inorganic component of human bone material, dental properties of the polymer composites were investigated. A visible light system was utilized to activate the acrylate resin matrix of the composites. Maximum loading percentage of HAP in composite was 65 wt% and the depth of cure was 6.0 mm which can be applicable for dental restoration. With increasing the HAP content, degree of conversion of polymer composites was slightly decreased, however, polymerization shrinkage value was not varied. Diametral tensile strength value was enhanced with an increase of HAP content, however, there was no strict trend between flexural strength and HAP concentration. Anyhow, polymer composites prepared herein have superior mechanical properties sufficient specifications applicable to dental materials.
Synthesis and Film Properties of Cross-linked Polysulfone with Imide Side Chain
Lee Eun-Sang ; Hong Sung-Kwon ; Kim Yong-Seok ; Lee Jae-Heung ; Kim In-Sun ; Won Jong-Chan ;
Polymer Korea, volume 30, issue 2, 2006, Pages 140~145
The mort commonly available substrate material is glass in the display fibrication process. However, glass is not desirable due to its heaviness and fragility. Recently, plastics such polysulfone (PSF), polyethesulfone (PES), polycarbonate (PC), polyethylene terephthalate (PET) and cyclic olefin polymers (COP) have been investigated to replace glass as a substrate material for display fibrication. Plastic substrates are advantageous in that they are lightweight, huh impart resistance, flexibility, and ability for roll to roll manufacturing process. But many plastics have poor chemical resistance in organic solvent. The chemica resistance is also lequired because they are exposed to solvents for various chemical treatments din the manufacturing process. So, we have an interest in the chemical modification of PSF to improve chemical resistance. We introduced crosslinkable imide moieties using chloromethylation method for the modification of PSF which could be overcome above shortcomings for display substrate based on plastic film. We prepared the cross-linked polysulfone films which were represented chemical resistance in HeOH, THF, DMSO and NMP. The thermal properties were measured by TGA, DSC and TMA. As the results, we have confirmed to enhance of the thermal property. They had low coefficient of thermal expansion (CTE) which decreased to 15% and had increased
. Cross-linked polysulfone films with imide side-chain had good optical properties and chemical resistance so that they could be used as flexible display substrate.
Synthesis and Characterization of Linear and Branched Copolymers of Poly(ethylene glycol) and
Hyun Hoon ; Kim Moon-Suk ; Khang Gil-Son ; Rhee John-M. ; Lee Hai-Bang ;
Polymer Korea, volume 30, issue 2, 2006, Pages 146~151
Linear and branched copolymers consisting of poly(ethylene glycol) (PEG) and
(PCL) were prepared to compare the characterization of star-shaped copolymers with various molecular architecture. Linear and branched PEG-PCL (1-arm, 2-arm, 4-arm, and 8-arm) copolymers were synthesized by the ring-opening polymerization of
in the presence of HCl
as a monomer activator at room temperature. The synthesized copolymers were characterized with
, GPC, DSC, and XRD. As a result of the DSC and XRD, each copolymers showed different thermal properties and crystallinity according to the number of ms. The micellar characterization of linear and branched copolymers in an aqueous phase was carried out by using NMR, dynamic light scattering, AM, and fluorescence techniques. The critical micelle concentration (CMC) and diameters of micelles depended on the number of arms. Most micelles exhibited a spherical shape in AFM. In this study, we characterized star-shaped PEG-PCL copolymers and investigated their molecular architecture effect on the various properties. Furthermore, we confirmed that the micelles termed with linear and branched PEG-PCL copolymers have possibility as a potential hydrophobic drug delivery vehicle.
Preparation and Properties of Waterborne Polyurethanes Based on Mixtures of Hydroxy-Terminated Polybutadiene and Poly(propylene glycol)
Lee Seon-Suk ; Lee Si-Ho ; Lee Dai-Soo ;
Polymer Korea, volume 30, issue 2, 2006, Pages 152~157
Anionic or Zwitter-ionic waterbone polyurethanes (WPU) based on mixtures of hydroxy terminated poly-butadiene and poly(propylene glycol) were prepared and their physical properties were characterized. Particle size of WPU increased with increasing the content of HTPB. It was observed that the microphase separation of soft segments and hart segments increased with increasing the content of HTPB in the WPUs. Zwitter-ionic WPU showed stronger hydrogen bonds between molecules than anionic WPU after drying. Polyurethane films obtained after drying of WPUs exhibit besmechanical properties when the HTPB content among polyols for WPUs were 25wt%. It is postulated that such mechanical properties resulted from different microphase separation of soft segments and hard segments of polyurethane films obtainec after drying of WPUs.
Thermal and Optical Properties of Heat-Resistant Core Materials in Plastic Optical Fiber
Lee Gyu-Ho ; Cho Won-Keun ; Park Min ; Lee Hyun-Jung ;
Polymer Korea, volume 30, issue 2, 2006, Pages 158~161
Recently the application of plastic optical fiber (POF) in automotives and planes demands the heat-resistant and high refractive index con materials. We synthesized polyglutarimides (PGIs) via imidization of PMMA with primary amines under high pressure and high temperature and investigated thermal and optical properties by varying the molar ratio of amines and the type of amines (ethyl amine vs. isopropyl mine). The degree of imidization was calculated based on the peak intensity in
NMR and FTIR. We found that the glass transition temperature
of PGIs increased over
compared to the traditional core materials in POF, PMMA, and they are stable up to
. PGIs anthesized with ethyl mine show the better heat resistance than those with isopropyl amines. Additionally, they show the comparable transparency and higher refractive index than PMMA. It implies that they can be utilized as the excellent photo-efficient and heat-resistant core materials in POF.
Synthesis and Characterization of New Positive Type Photosensitive Poly(amic acid)s
Sim Hyun-Bo ; Yu Yeong-Im ; Yi Mi-Hye ;
Polymer Korea, volume 30, issue 2, 2006, Pages 162~167
Polyamic acid (PAA) was prepared from cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) and 4,4'-fiaminodiphenyl ether (DDE). In order to impart a photosensitivity to the PAA, diazonaphthoquinone (DNQ) derivative (DI) was added. However, the addition of the DI was not enough to inhibit the dissolution of the PAA for a aqueous alkal solution. Therefore, we had synthesized poly(amic acid ester)s by an adding 1,2-epoxy-3-phenoxypropane to the PAA. That is, an acidity of the PAA could be controlled by an esterification reaction of 1,2-epoxy-3-phenoxypropane with the PAA. Significant difference of a dissolution rate of the poly(amic acid ester) between an o(posed and unexposed area was observed at an acid content of 60% and less. Resolution of the positively patterned film showed about
at the exposure dose of
Optimal Hydrophilization and Chondrocyte Adhesion of PLLA Films and Scaffolds by Plasma Treatment and Acrylic Acid Grafting
Yang Hee-Seok ; Park Kwi-Deok ; Ahn Kwang-Duk ; Kim Byung-Soo ; Han Dong-Keun ;
Polymer Korea, volume 30, issue 2, 2006, Pages 168~174
To utilize as highly functional scaffolds for tissue engineering by improving hydrophobicity and cell compatibility of the exist polymer scaffolds, the biodegradable poly(L-lactic acid) (PLLA) films and scaffolds having the optimal hydrophilicity were prepared by in situ plasma treatment and grafting of a carboxyl acid-containing monomer, acrylic acid (AA) in the chamber. From the results of surface analyses, surface-modified nonporous PLLA film and dual pore scaffold surfaces showed high hydrophilicity due to the decrease in contact angle and the increase in carboxylic groups as compared with untreated PLLA control. In particular, among various surface modification methods, Ar(argon)+AA+AA sample prepared by Ar plasma and then acrylic acid treatments displayed lower contact angle and more carboxylic groups thar Ar/AA and Ar+TP(thermal polymerization) samples, indicating that Ar+AA+AA sample was optimally treated for improving its hydrophilicity. In the cases of surface modified nonporous PLLA films and dual pore scaffolds, the adhesion and proliferation of chondrocytes increased with increasing their hydrophilicity.
Structure Variation of Polypropylene Hollow Fiber Membrane with Operation Parameters in Stretching Process
Lee Gyu-Ho ; Kim Jin-Ho ; Song Ki-Gook ; Kim Sung-Soo ;
Polymer Korea, volume 30, issue 2, 2006, Pages 175~181
Hybrid process of thermally-induced phase separation and stretching was developed for the preparation of microporous polypropylene hollow fiber membranes. Precursor for stretching was prepared by using soybean oil as a diluent and benzoic acid as a nucleating agent far the sphenlite control and it was stretched far the micrporous hollow fiber membrane. The effects of stretching ratio and deformation rate for stretching process were investigated. Increase of stretching ratio resulted in the greater pore size with nonuniform size distribution. Higher deformation rate also increaser the pore size with uniform size distribution. Stretching ratio was closely related with the orientation of polymer chain and increased the mechanical strength of the fiber. Increase of deformation rate had little effects on the orientation of crystalline phase, and decreased the orientation of amorphous phase which caused the decrease of tensile strength of the fiber and broke the micro-fibrils connecting spherulites to form a circular pore shape.
Pitch Variations in Cholesteric Liquid Crystals by Phase Separation
Park Han-Soo ; Kim Beom-Kyung ; Kim Whan-Ki ; Kim In-Sun ; Song Ki-Gook ;
Polymer Korea, volume 30, issue 2, 2006, Pages 182~186
Due to their periodic helical structure, cholesteric liquid crystals (CLC) have a unique ability to selectively reflect light. CLC films reflecting a broad wavelength band were prepared by inducing a pitch gradient in CLC layer through a phase separation. The reflection bandwidth of the CLC cell was broaden as irradiation light intensity decreased and as the amount of the UV absorbing dye increased. Initial reflection bandwidth of 50 nm was broaden to 300 nm Various pitch distributions in the CLC cell was observed using SEM and ATR-IR technique was used to prove that the pitch distributions are induced through the phase separation.