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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 37, Issue 6 - Nov 2013
Volume 37, Issue 5 - Sep 2013
Volume 37, Issue 4 - Jul 2013
Volume 37, Issue 3 - May 2013
Volume 37, Issue 2 - Mar 2013
Volume 37, Issue 1 - Jan 2013
Selecting the target year
Effect of Silk in Silk/PLGA Hybrid Films on Attachment and Proliferation of Human Aortic Endothelial Cells
Lee, Jihye ; Lee, Sojin ; Kim, Seulji ; Kim, Kyounghee ; Kim, Younglae ; Song, Jeongeun ; Lee, Dongwon ; Khang, Gilson ;
Polymer Korea, volume 37, issue 2, 2013, Pages 127~134
DOI : 10.7317/pk.2013.37.2.127
The vascular endothelial cells are the inner layers of blood vessels. It regulates the function of blood vessels and proliferation of vascular smooth muscle cells. Poly(lactide-co-glycolic acid) (PLGA) is a biodegradable synthetic polymer with a well-controlled degradation rate and an acceptable mechanical strength. It can be easily fabricated into many shapes. Silk consists of 18 amino acids. It found important for attaching cells cultured in vitro, and maintaining cell functions. In this study, we fabricated silk/PLGA biomaterial hybrid films of 0, 10, 20, 40 and 80 wt% silk. We performed MTT, SEM, ELISA, and immunocytochemistry analyses. We confirmed the adhesion and the proliferation of HAECs on silk/PLGA according to the content of silk, and 40 wt% silk/PLGA hybrid films have superior adhesion and proliferation properties. These results demonstrate that silk/PLGA hybrid films provide suitable surfaces for HAECs, and there is the effect of silk on cell growth and proliferation.
pH Effect on Relaxation Spectra of Poly(methyl acrylate)-Poly(acrylonitrile) Copolymers by REM Model
Kim, Nam Jeong ;
Polymer Korea, volume 37, issue 2, 2013, Pages 135~140
DOI : 10.7317/pk.2013.37.2.135
The stress relaxation of poly(methyl acrylate)-poly(acrylonitrile) copolymer samples was carried out in air, distilled water, pH 3, 7 and 11 solutions at various temperatures using a tensile tester equipped with a solvent chamber. The relaxation spectra of poly(methyl acrylate)-poly(acrylonitrile) copolymers were obtained by applying the experimental stress relaxation curves to the equation of relaxation spectrum derived from the Ree-Eyring and Maxwell model. The determination of relaxation spectra was performed from computer calculation using a Laplace transform method. It was observed that the relaxation spectra of these samples are directly related to the distribution of molecular weights and self-diffusions of flow segments.
Effects of PLGA/Fibrin Scaffolds on Attachment and Proliferation of Costal Cartilage Cells
Song, Jeong Eun ; Lee, Yujung ; Lee, Yun Me ; Cho, Sun Ah ; Jang, Ji Eun ; Lee, Dongwon ; Khang, Gilson ;
Polymer Korea, volume 37, issue 2, 2013, Pages 141~147
DOI : 10.7317/pk.2013.37.2.141
Poly(lactide-co-glycolic acid) (PLGA) has been widely used in the drug delivery and tissue engineering applications because of its good mechanical strength and biodegradation profile. However, cell attachment to the scaffold is low compared with that on fibrin although cells can be attached to the polymer surface. In this study, PLGA scaffolds were soaked in cells-fibrin suspension and polymerized with dropping fibrinogen-thrombin solution. Cellular proliferation activity was observed in PLGA/fibrin-seeded costal cartilage cells (CC) on 1, 3, and 7 days using the MTT assay and SEM. The effects of fibrin on the extracellular matrix (ECM) formation were evaluated using CC cell-seeded PLGA/fibrin scaffolds. The PLGA/fibrin scaffolds elicited more production of glycosaminoglycan (GAG) and collagen than the PLGA scaffold. In this study, fibrin incorporated PLGA scaffolds were prepared to evaluate the effects of fibrin on the cell attachment and proliferation in vitro and in vivo. In this result, we confirmed that proliferation of cells in PLGA/fibrin scaffolds were better than in PLGA scaffolds. The PLGA/fibrin scaffolds provide suitable environment for growth and proliferation of costal cartilage cells.
Properties of Polymer Cement Mortar Based on Styrene-Butyl Acrylate according to Emulsifier and Monomer Ratios
Jo, Youngkug ; Hyung, Wongil ;
Polymer Korea, volume 37, issue 2, 2013, Pages 148~155
DOI : 10.7317/pk.2013.37.2.148
The purpose of this study is to clarify the effect of the emulsifier ratio on the properties of the polymer cement mortars based on styrene-butyl acrylate (S/BA) latexes, and to obtain necessary basic data to develop appropriate latexes for cement modifiers. The polymer dispersions for cement modifiers was synthesized using styrene and butyl acrylate. Polymer cement mortars based on S/BA latexes were prepared with various monomer and emulsifier ratios, and their water-cement ratio, air content, flexural and compressive strengths, water absorption and chloride ion penetration were tested. From the test results, the maximum flexural and compressive strengths of polymer cement mortars based on S/BA latexes were obtained at a bound styrene content of 60% and an emulsifier ratio of 6%. Also, the water absorption and chloride ion penetration depth are greatly affected by the polymer-cement ratio rather than the bound styrene and emulsifier content. Accordingly, it is judged that S/BA latexes can be used place of the conventional polymer dispersions of cement modifier.
Effect of Phenolic Antioxidants System on Yellowing of Amorphous Poly-α-olefin
Kim, Si-Yong ; Kim, Ho-Gyum ; Park, Sang-Cheol ; Min, Kyung-Eun ;
Polymer Korea, volume 37, issue 2, 2013, Pages 156~161
DOI : 10.7317/pk.2013.37.2.156
Phenolic antioxidants are effective stabilizers that provide excellent long-term heat stability by preventing thermo-oxidative degradation during processing and service life. However, under a selected set of circumstances, certain types of phenolics have been susceptible to discoloration due to prolonged storage in an environment containing oxides of nitrogen. It is investigated that the effect of addition of secondary antioxidant and chemical structure of primary antioxidant on discoloration of amorphous poly-
-olefin (APAO), which is especially prone to be decomposed in high processing temperature. From the result, it is concluded that a higher level of steric hindrance of phenolic antioxidant provided by long alkyl chain allows a more enhanced synergic effect with secondary antioxidant.
Adhesion Behavior of Graphene Oxide on Spherical Polymer Particles
Kim, Sinwoo ; Lee, Sang-Soo ; Lee, Jonghwi ;
Polymer Korea, volume 37, issue 2, 2013, Pages 162~166
DOI : 10.7317/pk.2013.37.2.162
Graphene-coated polymer particles have attracted research interests due to their emerging applications derived from their controlled structure and morphology. To control the properties of graphene oxide (GO)-polystyrene (PS) composite particles, the adsorption time and instantaneous adsorption conditions were investigated by varying their mixing method. Polystyrene particles prepared by emulsion polymerization were modified to have positive surface charge by adsorption of polyethylene imine (PEI) on the surface of PS particles. GO prepared by the chemical exfoliation method had negative surface charge from the oxygenated groups. The adsorption of the negatively charged GOs onto the positively charged PS particles was successfully completed, and it was found that a longer adsorption time and a greater difference in the instantaneous relative concentration led PS-GO particles to have more homogeneously coated surfaces without aggregation.
Synthesis and Characterization of Waterborne Polyurethanes Based on Isophorone Diisocyanate and Mixed Polyols of Poly(tetramethylene glycol)/Polydimethylsiloxane Diol
Lee, Ji Hye ; Hong, Seongdon ; Kim, Young Ho ;
Polymer Korea, volume 37, issue 2, 2013, Pages 167~176
DOI : 10.7317/pk.2013.37.2.167
Linear and cross-linked waterborne polyurethanes (WPUs) based on isophorone diisocyanate and mixed diols of poly(tetramethylene glycol)/hydroxyethyl-terminated polydimethylsiloxane (PDMS-OH) were synthesized with dimethylol propionic acid as an anionic component, trimethylolpropane as a cross-linking agent, and butanediol as a chain extender and characterized. The hydrophobicity,
, stress-strain behaviors of the linear or cross-linked siloxane-containing WPU (WPU-Si) films with different PDMS content were analyzed by using water contact shape analyzer, energy dispersive spectrometer, dynamic mechanical analyzer, and universal testing machine. The results reveal that as the PDMS content increased, the hydrophobicity of WPU-Si films increased,
moved to higher temperature, the breaking stress increased, and the breaking strain decreased.
Surface Characterization of Poly(vinylidene fluoride) and Poly(methyl methacrylate) Blend Coatings Prepared by Dispersion Coating
Seok, Kwang Hee ; Ha, Jong-Wook ; Lee, Soo-Bok ; Park, In Jun ; Kim, Hyung Joong ;
Polymer Korea, volume 37, issue 2, 2013, Pages 177~183
DOI : 10.7317/pk.2013.37.2.177
Surface properties such as morphology, crystalline structure, and chemical composition of poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blend coatings prepared by dispersion coating on poly(ethylene terephthalate) (PET) film have been investigated. It was observed that the surface properties were greatly influenced by the coating temperature and blend composition according to SEM, ATR-FTIR and XPS analysis. The typical surface morphology of
-crystalline structure of PVDF could be observed when the coating temperature was lower than
or the amount of PVDF was higher than 80 wt% in the blend. Otherwise, the crystalline structure was changed from
-crystal or amorphous state. Based on the XPS analysis, the surface segregation of PVDF chains in the blend coating was confirmed.
Effect of Acrylic Acid Contents and Inorganic Fillers on Physical Properties of Acrylic Pressure Sensitive Adhesive Tape by UV Curing
Kim, Dong-Bok ;
Polymer Korea, volume 37, issue 2, 2013, Pages 184~195
DOI : 10.7317/pk.2013.37.2.184
Acrylic pressure sensitive adhesive (PSA) tapes were used for the automotive, the electrical and the electronic industries and the display module junction. In this study, the manufacture of high-strength structural tape used 2-ethylhexyl acrylate (2-EHA) and acrylic acid (AAC), and UV irradiation for photo-polymerization, and the semi-structural properties of acrylic PSA tape with the AAC content and inorganic filler
content were investigated. The initial adhesion strength was lowered by the rigidity of molecule chains due to the use of AAC, and the adhesion strength increased with increasing wetting time. The wetability, contact angle, and SEM images of PSA tapes with various contents of AAC were determined. Without filler, the peel strength and dynamic shear strength of PSA tape showed inverse correlation but the peel strength and dynamic shear strength increased with increasing filler content. From these correlations the PSA tapes could be optimized for the applications requiring high performance.
Effect of Surface Modification Process Conditions on Properties of Aramid Paper
Sha, Lizheng ; Zhao, Huifang ;
Polymer Korea, volume 37, issue 2, 2013, Pages 196~203
DOI : 10.7317/pk.2013.37.2.196
Surface modification of meta-aramid fibers was performed by phosphoric acid treatment. Surface morphology and element composition of untreated and treated fibers were analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Effects of surface modification on the mechanical strength of aramid papers made from meta-aramid fibers and fibrid were investigated. Surface modification conditions were optimized by response surface analysis (RSA). Results show that phosphoric acid treatment increases the surface roughness and oxygen content of aramid fibers. They improve the interface bonding strength between aramid fibers and fibrid, which improves the tensile strength of aramid papers. The results of response surface analysis indicate that the tensile strength of aramid papers increases by 47.5% and reaches the maximum when meta-aramid fibers are treated with 21.1wt% phosphoric acid solution at
for 36.7 min.
Effects of Melt-blending Condition and Additives on Mechanical Properties of Wood/PP Composites
Ahn, Seong Ho ; Kim, Dae Su ;
Polymer Korea, volume 37, issue 2, 2013, Pages 204~210
DOI : 10.7317/pk.2013.37.2.204
Effects of additives (lubricant and antioxidant) and melt-blending condition (temperature, time and rotor speed) on the mechanical properties of polypropylene-based wood polymer composites (WPCs) were investigated. WPCs were prepared by melt-blending followed by compression molding. To understand melt-blending procedure, torque change of the WPC melt-blend was monitored. Maleic anhydride modified PP and nanoclay were used as a compatibilizer and a reinforcing filler, respectively. UTM and izod impact tester were used to measure the mechanical properties of the WPCs and a color-difference meter was used to measure the discoloration of the WPCs according to melt-blending condition. The mechanical properties showed that the optimized melt-blending condition was
, 15 min, and 60 rpm. The mechanical properties of the WPCs decreased with increasing lubricant and antioxidant content. The two step method, adding wood flour later separately during melt-blending, was more effective than the typical one step method for improving the mechanical properties of the WPCs.
Synthesis and Characterization of Very High Molecular Weight Nylon 4 and Nylon 4/6 Copolymers
Kim, Nam Cheol ; Kim, Ji-Heung ; Nam, Sung Woo ; Jeon, Boong Soo ; Yoo, Young-Tai ; Kim, Young Jun ;
Polymer Korea, volume 37, issue 2, 2013, Pages 211~217
DOI : 10.7317/pk.2013.37.2.211
Potassium tert-butoxide (t-BuOK) with
or benzoyl chloride (BzC) as a polymerization initiator system was used with crown ether or TMAC as catalyst to synthesize very high molecular weight nylon 4 homo- and copolymers by anionic ring opening polymerization. Effect of different amounts of catalyst, crown ether and TMAC on the polymerization was studied in terms of intrinsic viscosity, yield and thermal properties. By adding crown ether or TMAC, polymers with very higher intrinsic viscosity values were obtained in a high yield. It was possible to synthesize nylon 4 homopolymer with such a high intrinsic viscosity value of 6.36 dL/g. Crown ether was found to be more efficient in terms of intrinsic viscosity and polymer yields than TMAC. Thermal analysis confirmed that molecular weight effect on the thermal properties of both nylon 4 and nylon 4 copolymer was marginal.
Syntheses and Characterizations of Position Specific Functionalized Graphenes
Heo, Cheol ; Chang, Jin-Hae ;
Polymer Korea, volume 37, issue 2, 2013, Pages 218~224
DOI : 10.7317/pk.2013.37.2.218
Graphene oxide (GO) was prepared by the Hummers and Offeman method from graphite. Two different types of functionalized graphene sheets (FGSs) were synthesized by using GO. Hexamethylamine (HDA) substituted vertically to the graphene sheet (Ver-HDA-GS) was synthesized from HDA and epoxy group in GSs. Whereas, horizontally substituted hexadecanol (HDO) to the GS(Hor-HDO-GS) was synthesized from HDO and alcohol groups via reduced GO (RGO), respectively. The structures of the GO, RGO, Ver-HDA-GS, and Hor-HDO-GS were identified by Fourier transform infrared (FTIR). In addition, we examined the thermal stability and morphology. Atomic force microscope (AFM) disclosed that Ver-HDA-GS consisted of one- or two-layer graphene regions. However, the Ver-HDA-GS layers showed average thickness of 1.76 nm. The thermal stabilities of the FGSs were better than those of the GO and RGO. The Ver- HDA-GS was well dispersed in common solvents such as dimethyl sulfoxide (DMSO), toluene, chloroform, and decalin.
Characterization of Poly(vinyl alcohol) Nanocomposite Films with Various Clays
Ham, Miran ; Kim, Jeong-Cheol ; Chang, Jin-Hae ;
Polymer Korea, volume 37, issue 2, 2013, Pages 225~231
DOI : 10.7317/pk.2013.37.2.225
Poly(vinyl alcohol) (PVA) hybrid films containing 5 wt% pristine clay mineral were synthesized in the water solution. The various PVA hybrid films were synthesized from structurally different pristine clays: saponite (SPT), montmorillonite (MMT), hectorite (SWN), hydrophilic bentonite (PGV), and mica (Mica). The thermo-optical properties and morphologies of the PVA hybrid films were evaluated with various pristine clays. The nanostructure of the hybrid films was observed using transmission electron microscopy, which showed that the clay layers were well dispersed into the matrix polymer, although some clusters or agglomerated particles were also detected. The addition of pristine clay was more effective with regard to improving the thermal properties and gas barrier characteristics, whereas the optical transparency of the PVA hybrid films deteriorated with pristine clay.
Preparation and Characterization of Polyurethane Bioadhesive from Hydroxyl-terminated Polylactide and Imidazole-blocked Isocyanate
Shen, Tengfei ; Sun, Yingjuan ; Sun, Chunfeng ; Lu, Mangeng ;
Polymer Korea, volume 37, issue 2, 2013, Pages 232~239
DOI : 10.7317/pk.2013.37.2.232
A series of novel imidazole-blocked diisocyanate bioadhesives (IBAs) were synthesized from reaction of toluene 2, 4-diisocyanate (TDI), isophorone diisocyanate (IPDI), hydroxyl-terminated polylactide (HO-PLA-OH), 1,1,1-trimethylolpropane (TMP), and imidazole. Synthesis of IBAs was confirmed by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) revealed that the TDI-based IBA had lower thermal dissociation temperature and a faster deblocking rate than IBA based on IPDI. Hydroxyl-terminated polyurethane (HPU) was introduced to study the adhesive effect of the synthesized IBAs. Improvement on elastic modulus, tensile strength and water resistance of IBA-modified HPU in comparison with neat HPU suggested the good adhesive effect of IBA due to the strong chemical reaction between released NCO groups from IBA and hydroxyl groups from HPU.
Study on Cure Behavior of Low Temperature and Fast Cure Epoxy with Mercaptan Hardener
Eom, Se Yeon ; Seo, Sang Bum ; Lee, Kee Yoon ;
Polymer Korea, volume 37, issue 2, 2013, Pages 240~248
DOI : 10.7317/pk.2013.37.2.240
The curing behaviors of diglycidyl ether of bisphenol A (DGEBA) with mercaptan hardener were studied by the comparison with amine-adduct type hardener. Curing behaviors were evaluated by DSC at dynamic and isothermal conditions. In the DSC, the dynamic experiments were based on the method of Kissinger's equation, and the isothermal experiments were fitted to the Kamal's kinetic model. Activation energy of epoxy/amine-adduct type hardener was ca. 40 kcal/mol. As the functional group of mercaptan hardener, -SH increased, on epoxy/mercaptan hardeners, the activation energies decreased from 28 to 19 kcal/mol. Epoxy/amine-adduct type hardener was initiated at
or higher. However, epoxy/mercaptan hardeners reduced the initiation temperatures below
and shortened the durations of curing reaction within 10 min. We found out that the reaction kinetics of epoxy with mercaptan hardener followed the autocatalytic reaction models, and the maximum reaction rates were shown at the conversions of 20~40%.
Fabrication and Characterization of Environmentally Friendly PLA/PPC/PLA Multilayer Film
Lee, Deuk-Young ; Kim, Kyung-Youn ; Cho, Misuk ; Nam, Jaedo ; Lee, Youngkwan ;
Polymer Korea, volume 37, issue 2, 2013, Pages 249~253
DOI : 10.7317/pk.2013.37.2.249
From poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC) synthesized using
, a PLA/PPC/PLA layered film is prepared by coextrusion and then stretched to uniaxial orientation. The mechanical, optical, and barrier properties and shrinkage of the prepared film were investigated in detail. The maximum shrinkage of PLA/PPC/PLA film reached to 60% at
. With increasing PPC content, the ratio of shrinkage of the film was increased and its shrinkagerate was increased. The ratio of shrinkage of the film decreased with increasing stretching temperature. The prepared film has oxygen and vapor transmission barrier properties. In this study, the PLA/PPC/PLA film is expected to be commercialized as a environmentally friendly shrinkable film.