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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 28, Issue 6 - Nov 2004
Volume 28, Issue 5 - Sep 2004
Volume 28, Issue 4 - Jul 2004
Volume 28, Issue 3 - May 2004
Volume 28, Issue 2 - Mar 2004
Volume 28, Issue 1 - Jan 2004
Selecting the target year
Synthesis of Photoresist Using Environmental-benign Supercritical
Polymer Korea, volume 28, issue 6, 2004, Pages 445~454
The requirement for a much finer line width circuits on semiconductors needs new developers such as supercritical fluid to prevent the collapse of the photoresist micro-patterns. The copolymers contain t-butyl methacrylate having an acid-cleavable t-butyl group and supercritical fluid
soluble perfluorinated decyl methacrylate segments. The supercritical fluid
-philic properties of the photoresist changed to supercritical fluid
-phobic properties after the deprotection reaction by exposure, which made the exposed resist insoluble in the supercritical fluid
developer. The synthesized copolymers containing more than 30% of perfluorinated decyl methacrylate were found to be soluble in supercritical fluid
. The variation of film thickness before and after exposure was largest when the mole ratio of perfluorinated decyl methacrylate in the copolymer was 30%.
Ionic Conductivity Change Depending on Thermal History in PEO-LiC
Polymer Korea, volume 28, issue 6, 2004, Pages 455~459
Ionic conductivities of poly(ethylene oxide) (PEO)-based electrolytes are in a considerable inconsistency in many papers, varying more than three orders of magnitude for just same compositions. In PEO-salt-ceramic composite electrolytes, it has been also reported that the conductivity can be variant by almost three orders of magnitude according to thermal treatment and it has been regarded as a consequence of polymer-ceramic particle interaction. In this paper, we present a more systematic study on the change of ionic conductivity for ceramic-free PEO
polymer electrolytes, and found that the ionic conductivity can be variant more than hundred times according to thermal history. The slow recrystallization kinetics of PEO polymer is discussed to be responsible for the thermal history effect. Present results reveal that the effect of ceramic filler is not a main cause of the conductivity relaxation phenomenon.n.
Morphology and Mechanical Properties of Waste PVC Blends (II)- The Relationship between Rheology and Morphology of Waste PVC/PE Blends
Polymer Korea, volume 28, issue 6, 2004, Pages 460~467
The polymer blends of waste poly(vinyl chloride) (RPVC) and waste polyethylene (RPE) were prepared by melt mixing. Their morphologies and rheological properties were investigated and torque changes were also measured. Comparing the torques calculated by the log additivity rule with measured torque changes, the polymer blends showed the large negative deviation behavior (NDB) due to their incompatibility. The shear viscosities of the blends decreased with increasing shear rates, showing shear thinning behavior. The shear viscosity of the blends with compatibilizer was larger than that of the blends without compatibilizer. SEM micrographs of the strands after measurement showed that the domain size of the blends was slightly enlarged with increasing the shear rate. Also, RPVC domain size was larger in the core-sections of the strands from capillary viscometer than in the surface region.
Morphology and Mechanical Properties of Recycled PVC Blends (III) - Morphologies and Mechanical Properties of Recycled PVC/PE Blends with Different Kinds of Compatibilizers and Mixing Conditions
Polymer Korea, volume 28, issue 6, 2004, Pages 468~477
The polymer blends of waste poly(vinyl chloride) (RPVC) and waste polyethylene (RPE) were prepared by melt mixing. Various ethylene-vinyl acetate copolymers (EVA) and ethylene-methacrylic acid Na salt copolymer (ionomer) were used as compatibilizer. Their morphologies and mechanical properties were evaluated as a funtion of mixing sequence and time. EVA with high vinyl acetate contents showed a rapid increment of tensile properties when small amount was added. Tensile properties of the blends were gradually increased with the addition of ionomer. Morphologies of RPVC/RPE blends were analyzed by scanning electron microscopy. FT-IR data showed that EVA was a good compatibilizer in RPVC/RPE blend compared to ionomer. Mechanical properties of the blends were highly enhanced when RPVC and compatibilizer were mixed and first RPE was added later.
Effect of Types of Buffer Solution, pH and Soaking Time on the Water Uptake of Small Intestinal Submucosa Sheets
Polymer Korea, volume 28, issue 6, 2004, Pages 478~486
Small intestinal submucosa (SIS) is consisted with collagen and glycosaminoglycan as well as some growth factors which can stimulate cell activity. Recently, it has been recognized that SIS has been successfully examined in the bio-medical application as biomaterials without xenograft immune-rejection response. We prepared native SIS sheets and acid treated SIS sheets by acetic acid with 1 or 5-layered sheets, respectively. The water uptake ability of native and acid treated SIS sheets was examined to evaluate the possibility as wound dressings. Morphologies of SIS sheets were characterized by SEM and the effects of various buffer solutions and different pH solutions on the water uptake ability were observed for 16 days. We observed that the acid treated SIS sheets had higher water uptake ability than native SIS sheets. Also, the water uptake ability of these was slightly higher in various buffers than distilled water. In conclusion, this study suggests that native and acid treated SIS sheets could be useful for the applications of wound dressing and biodegradable injectable materials.
Effect of Interfacial Modification on the Characteristics of Poly(ethyl acrylate-co-t-butyl acrylate)/Silica Nanocomposites
Polymer Korea, volume 28, issue 6, 2004, Pages 487~493
The distribution of particles, in the mixture of poly(ethyl acrylate-co-t-butyl acrylate) (PEB) emulsion polymer and silica nanoparticles, was determined mainly depending on the pH of the mixture. The weak interfacial interaction was responsible for the severe coagulation of silica particles and the irregular dispersion for these nanocomposites. Methacryloxypropyltrimethoxysilane (MPS) was used to modify both the polymer and the silica. The nanocomposites which were prepared with these modified components had finer dispersion of silica nanoparticles and core-shell morphology due to the strong interfacial interaction. The strong hydrogen bonds were identified for these nanocomposites with FT-IR. The nanocomposites having strong interfacial interaction showed the increased glass transition temperature, the decreased ΔC
, and the increased decomposition temperature of the polymer chains. polymer chains.
Synthesis and Characterization of Photosensitive Polyimides Containing Alicyclic Structure
Polymer Korea, volume 28, issue 6, 2004, Pages 494~501
A new alkali developable photosensitive poly(amic acid) (PAA-0) with transmittance at 400 nm was synthesized from cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 2-(methacryloyloxy)ethyl-3,5-diamino-benzoate and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyl disiloxane in N-methyl-2-pyrrolidinone. Photosensitivity of the PAA-0 was investigated at 365-400 nm in the presence of a photoinitiator using a high pressure mercury lamp. The photo-cured poly(amic acid) was insoluble toward aqueous 2.38 wt% tetramethylammonium hydroxide solution. Negative pattern of the PAA-0 with 25
resolution was obtained by developing with 2.38 wt% tetramethylammonium hydroxide solution after exposure of 600 mJ/
in the presence of 2,2-dimethoxy-2-phenyl-acetophenone as a photoinitiator. The patterned poly(amic acid) was converted to polyimide by thermal curing at 25
for 50 min, which showed chemical resistance against photoresist stripper as well as good transmittance at 400 nm.
Surface Properties of Liposomes Modified with Poly(ethylenimine)
Polymer Korea, volume 28, issue 6, 2004, Pages 502~508
Cationic liposomes for cancer treatment have been developed in the field of chemotharpy. It was well combined on the surface of anionic tumor cell membrane by electrostatic interaction. Thus, the object of this study was to prepare the cationic liposomes capable of forming an ionic complex with the anionic cell membrane. To prepare the cationic liposomes, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) as a cationic lipid material and polyethylenimine (PEI) as a cationic polymer were synthesized. Ionic property on the surface of liposomes was determined by the zeta potential. The adsorption characteristics of plasma protein for liposome in bovine serum were determined by the particle size and turbidity change. To estimate the stability of liposome in buffered solution, the change of particle size was measured at room temperature for seven days. The cationic liposomes were absorbed a large amount of plasma protein in bovine serum because plasma protein having anionic charge was fixed on the surface of cationic liposomes. This result indicate that the modification on the surface of liposomes using cationic polyethylenimine enhances the protein adsorption in bovine serum. Additionaly, cationic liposomes showed good stability in buffered solution for seven days.
Microphase Separation and Crystallization in Binary Blends Consisting of Poly (methyl methacrylate)-block-Polystyrene Copolymer and Poly (vinylidene fluoride)
Polymer Korea, volume 28, issue 6, 2004, Pages 509~518
Microdomain structures and crystallization behavior of the binary blends consisting of an asymmetric block copolymer and a homopolymer were investigated using small-angle X-ray scattering (SAXS), optical micro scope (OM) and differential scanning calorimetry (DSC). Poly(methyl methacrylate)-block-polystyrene block copolymer (PMMA-b-PS) (weight fraction of PMMA =0.53) was mixed with low molecular weight poly(vinylidene fluoride) (PVDF). As the PVDF concentration was increased, the morphological change from a lamellar to a cylindrical structure occurred. The crystallization of PVDF significantly disturbed the orientation of the pre-existing microdomain structure, resulting in a poorly ordered morphology. In the blends, PVDF exhibited unique crystallization behavior due to the PMMA block which is preferentially miscible to PVDF and the space constraint imposed by the microdomains.
Compatibilization and Properties of Modified Starch-Poly(lactic acid) Blend
Polymer Korea, volume 28, issue 6, 2004, Pages 519~523
Starch was grafted with maleic anhydride by melt process and then the grafted starch was blended with poly(lactic acid). The thermal properties of the poly(lactic acid), poly(lactic acid)/starch, and poly(lactic acid)/ modified starch were observed by DSC and TGA analysis. In the case of poly(lactic acid)/modified starch, an additional melting peak at 1
accompanying with 172
assigned to pure poly(lactic acid) melting transition was clearly displayed in DSC analysis. Also, smooth decomposition pattern between starch and poly(lactic acid) was also monitored in poly(lactic acid)/modified starch blend by TGA analysis. The modulus of poly(lactic acid)/modified starch was 12％ higher than that of poly(lactic acid)/starch. The thermal and mechanical characteristics of poly(lactic acid)/modified starch might be due to the enhanced compatibilization between each components, which was also observed in SEM analysis.
Preparation of Polystyrene Particles Containing Poly(ethylene glycol) Groups and Their Surface Charge Characterization in Dielectric Medium
Polymer Korea, volume 28, issue 6, 2004, Pages 524~530
Polystyrene particles (PS) with poly(ethylene glycol) units on surface were formed by an emulsifier-free emulsion polymerization using styrene, poly(ethylene glycol) methacrylate (PEG-MMA) or poly(ethylene glycol) dimethacrylate (PEG-diMMA) at pH 7, and followed by freeze-drying to give the corresponding powders. The structures of PS particles were confirmed by FT-IR spectroscopy, and the particle size and distribution the PS particle were observed by scanning electron microscopy and particle analyzer. Monodisperse polymer particles were obtained at a concentration of PEG-MMA 2∼5 mol% or PEG-diMMA 1 mol% relative to styrene. The highest zeta potential of polymer surface was measured to be 183 mV at a polymer of PEG-MMA 5 mol%, which was measured in dielectric medium by means of ELS-8000 dynamic light scattering.
Synthesis and Properties of Photocurable Epoxy Modified Acrylates Using Half-Ester Acrylates
Polymer Korea, volume 28, issue 6, 2004, Pages 531~537
Various half-ester acrylates were prepared from anhydrides and 2-hydroxyethyl acrylate. Photocurable epoxy modified acrylates were prepared from synthesized half-ester acrylate and neopentylglycol diglycidylether. Physical properties such as hardness, yellowing, tensile strength and elongation were tested and compared as the structure of oligomer in cured-film differs. It was found that viscosity of neopentylglycol diglycidylether-hexahydrophthalic anhydride (NP-HA) was highest. Hardness and tensile strength of photocrosslinked neopentylglycol diglycidylether-hexahydrophthalic anhydride were better than those of other photocrosslinted epoxy acrylates. And 5% weight loss temperature of photocrosslinked neopentylglycol diglycidylether-hexahydrophthalic anhydride was higher than those of other photocrosslinked epoxy acrylates. Value of yellow index of photocrosslinked neopentylglycol diglycidyl ether-succinic anhydride (NP-SA) was lower than the other products.
Preparation of Insulin-Immobilized Polyurethane Films and Their Interaction with Fibroblasts
Polymer Korea, volume 28, issue 6, 2004, Pages 538~544
Polyurethanes containing L-lysine segments in the main chain (PULL) were synthesized from 4,4'-diphenymethyl diisocynate, poly(tetramethylene glycol), and z-lysine oligomer as a chain extender. Insulin-immobilized polyurethanes (PULL-In) were prepared by a coupling reaction of PULL surface amino groups with insulins. The amount of immobilized insulin was about 0.30 nmol/
, as determined by Bradford method. The interactions of NIH/3T3 fibroblasts with surface-modified PULLs were investigated using
H-thymidine incoporation and optical microscopy. The cell growth rate on PULL-In film was higher than those on other substrates. The cell proliferation by the immobilized insulin was almost same as that by the free one.
Refractive Index Changes of Polymer Film by Photochemical Reactions
Polymer Korea, volume 28, issue 6, 2004, Pages 545~550
The refractive index of thin copolymer film was controlled by photo-degradation of chromophores in the copolymer. FTIR and UV/Vis spectroscopy were employed to elucidate the effect of chemical structure on refractive index changes after photobleaching. The decrease of refractive index of the film by photobleaching can be ascribed to the decrease of polarizability of polymer molecules through breakage of C =C bond in the chromophore. Due to the selective photoreaction of the chromophores which align along the film plane, refractive index of the copolymer film measured in TE mode decreases faster than that in TM mode. Polarized ATR-FTIR spectroscopy was used to verify such a difference in refractive index of the film.
Preparation and Mechanical Properties of Nanocomposite of Cellulose Diacetate/Montmorillonite
Polymer Korea, volume 28, issue 6, 2004, Pages 551~555
Cellulose diacetate (CDA) nanocomposite films were prepared by using various plasticizer and montmorillonite nanofiller in methylene chloride/ethanol (9:1 w/w) mixed solution. The thermal property (T
) of prepared CDA films was observed by DSC and T
of the films was decreased with the increase in the plasticizer content. The degree of dispersion of MMT in the CDA film was observed by XRD and mechanical property of CDA film was measured by tensile strength and Young's modulus. When the plasticizer was added into the CDA film upto 30 wt%, the Young's modulus of film was decreased from 1930 MPa to 1131 MPa but was increased from 1731 MPa to 2272 MPa when the MMT was added into the film upto 7 wt%. The mechanical properties of CDA films were decreased by addition of plasticizer but strengthened by the incorporation of MMT.