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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 35, Issue 6 - Nov 2011
Volume 35, Issue 5 - Sep 2011
Volume 35, Issue 4 - Jul 2011
Volume 35, Issue 3 - May 2011
Volume 35, Issue 2 - Mar 2011
Volume 35, Issue 1 - Jan 2011
Selecting the target year
Effect of PLGA Scaffold Containing Demineralized Bone Solution for Articular Cartilage Tissue Engineering: In Vitro Test
Ahn, Woo-Young ; Kim, Hye-Lin ; Song, Jeong-Eun ; Lee, Dong-Won ; Khang, Gil-Son ;
Polymer Korea, volume 35, issue 6, 2011, Pages 499~504
Articular cartilage has an intrinsic difficulty in recovering damages, which requires its tissue engineering treatment. Demineralized bone particle (DBP) contains various bioactive molecules. It is widely used biomaterials in the field of tissue engineering. We developed the synthetic/natural hybrid scaffolds with poly(lactide-co-glycolide) (PLGA) and solution of DBP. The chondrocytes were seeded on the PLGA-DBP scaffolds and MTT assay, morphological observation, biological assay for collagen, sGAG, and RT-PCR were performed to analyze the effect of the DBP on cell viability and extracellular matrix secretion. In SEM observation, we observed that PLGA-DBP scaffolds had uniform porosity. As MTT assay showed scaffolds containing DB solution had higher cell viability then only PLGA scaffolds. The PLGA-DBP scaffolds had better ECM production than PLGA scaffold. It was proven by the higher specific mRNA expression in the PLGA-DBP scaffold than that in PLGA scaffold. These results indicated that PLGA-DBP scaffolds might serve as potential cell delivery vehicles and structural bases for in vitro tissue engineered articular cartilage.
Relation of Structural Features of Dinuclear Constrained Geometry Catalysts with Copolymerization Properties of Ethylene and 1-Hexene
Cao, Phan Thuy My ; Nguyen, Thi Le Nhon ; Nguyen, Thi Le Thanh ; Noh, Seok-Kyun ;
Polymer Korea, volume 35, issue 6, 2011, Pages 505~512
Effects of structural features of 4 dinuclear constrained geometry catalysts having paraxylene derivative bridge (DCGC) on copolymerization of ethylene and 1-hexene were investigated. The bridges of three catalysts have para-xylene backbone with a different substituent at benzene ring. The substituents were hydrogen (Catalyst 1), isopropyl (Catalyst 2), n-hexyl (Catalyst 3) and 1-octyl (Catalyst 4). It was found that Catalyst 1 having hydrogen as a substituent exhibited the greatest activity among the four dinuclear CGCs. On the other hand, Catalyst 2 containing isopropyl as a substituent showed the smallest activity. Very interestingly, Catalyst 2 was able to produce about 6 times higher molecular weight polymer than Catalyst 3 and 4. Catalyst 3 and 4 having a long alkyl chain substituent revealed the biggest comonomer response to generate polyethylene copolymer containing more than 40% 1-hexene contents. These results suggest that the control of the substituent of para-xylene bridge of dinuclear CGC can provide a proper method to adjust the microstructure of polyethylene copolymers.
Molecular Simulation Studies for Penetrable-Sphere Model: II. Collision Properties
Kim, Chun-Ho ; Suh, Soong-Hyuck ;
Polymer Korea, volume 35, issue 6, 2011, Pages 513~519
Molecular simulations via the molecular dynamics method have been carried out to investigate the dynamic collision properties of penetrable-sphere model fluids. The collision frequencies, the mean free paths, the angle distributions of the hard-type reflection and the soft-type penetration, and the effective packing fractions are computed over a wide range of the packing fraction
and the repulsive energy
. The soft-type collisions are dominated for lower repulsive energy systems, while the hardtype collisions for higher repulsive energy systems. Very interestingly, the ratio of the soft-type (or, the hard-type) collision frequency to the total collision frequency is directly related with the Boltzmann factor of acceptance (or rejection) probabilities in the canonical ensemble Monte Carlo calculations. Such dynamic collision properties are shown to be restricted for highly repulsive and dense systems of
, indicating the cluster forming structures in the penetrable-sphere model.
Preparation of Eudragit Coated Superporous Hydrogels and Their pH Dependent Swelling Behavior
Kim, Bo-A ; Baek, Eun-Jung ; Huh, Kang-Moo ;
Polymer Korea, volume 35, issue 6, 2011, Pages 520~525
Superporous hydrogels (SPHs) with fast swelling and superabsorbent properties are useful materials in various biomedical fields, by improving the swelling properties of conventional hydrogels based on their unique porous structure. In this study, Eudragit polymers were used as coating materials to control the swelling properties of poly(acrylic acid-co-acrylamide) based SPHs by environmental pH. The SPHs were coated with Eudragit L100 and S100 that have different pH characteristics as enteric coating materials by a dip coating method, and their pH dependent swelling behaviors were observed in various pH environments. The swelling of SPHs was inhibited at a low pH range, but significantly enhanced above a characteristic pH of Eudragit polymers. This pH dependent swelling behavior of hydrogels could be modulated by the characteristics of the enteric coating polymers.
Polymerization and Characterization of Polyesters Using Furan Monomers from Biomass
Seo, Kang-Jin ; Kim, Myeong-Jun ; Jeong, Ji-Hea ; Lee, Young-Chul ; Noh, Si-Tae ; Chung, Yong-Seog ;
Polymer Korea, volume 35, issue 6, 2011, Pages 526~530
Furan-2,5-dicarboxylic acid (FDCA) was synthesized by
oxidation of 2,5-dihydroxymethylfuran(DHMF) derived from biomass. Polyesters were synthesized by esterification and polycondensation of FDCA with various diols(ethane-1,2-diol, propane-1,3-diol, butane-1,4-diol, hexane-1,6-diol, decane-1,10-diol). The composition of polyesters was characterized by using
NMR. Thermal properties of the polyesters were characterized by DSC and TGA. Intrinsic viscosities(IV) of the polyesters were measured to be 0.78~1.2 dL/g comparable with IV of commercial poly(ethylene terephthalate)(PET). As the chain lengths of diols increased, Young's modulus and strength decreased and elongation-to-break generally increased. Young's modulus and strength of the polyesters were measured to be 3551 MPa and 103 MPa, respectively, comparable with commercial PET.
Homopolymer Distribution in Polystyrene - Poly(methyl methacrylate) Diblock Copolymer
Hong, Sung-Ho ; Lee, Eun-Ji ; Song, Kwon-Bin ; Lee, Kwang-Hee ;
Polymer Korea, volume 35, issue 6, 2011, Pages 531~536
Homopolymer distribution in block copolymer/homopolymer blends was investigated as a function of homopolymer concentration and homopolymer molecular weight. The deuterated poly(methyl methacrylate) or polystyrene was blended with a deuterated polystyrene-poly(methyl methacrylate) diblock copolymer up to a concentration of 20 wt%. Samples were characterized by small-angle X-ray scattering (SAXS), neutron reflectivity and transmission electron microscopy. The block copolymer with a thin-film geometry formed alternating lamellar microdomains oriented parallel to the substrate surface. By adding the homopolymer, the microdomain structure was significantly disturbed. As a consequence, a poorly ordered morphology appeared when the homopolymer concentration exceeded 15 wt%. Increasing the homopolymer concentration and/or the homopolymer molecular weight caused the microdomains to swell less uniformly, resulting in segregation of the homopolymer toward the middle of the microdomains.
Fracture Behavior of Polycarbonate/Polyestercarbonate Blends
Lee, Yong-Bum ; Lee, Choon-Soo ; Kim, Dae-Sik ; Kim, Jong-Hyun ; Jho, Jae-Young ; Lee, Sang-Soo ;
Polymer Korea, volume 35, issue 6, 2011, Pages 537~542
Fracture behaviors of polycarbonate (PC)/polyestrercarbonate (PEC) blends and their miscibility have been examined to find out the mechanism of ductilie-brittle transition of fracture behavior which would be a main governing factor on the thickness sensitivity of impact strength of PC.
measurement showed that PEC with a carbonate content higher than 30 mol% was miscible with PC. In the notched Izod impact test of PC, ductile-brittle transition occurred in the range of 4 to 5 mm thickness. The impact strength of miscible PC/PEC5 blends ductile-fractured in the thin specimens decreased with increasing PEC5 content, which was in accordance with the decrease of elongation at break in tensile test. In the brittle fracture of the thick specimens, the impact strength was well correlated with the plastic zone size in the vicinity of the notch tip.
Influence of Polymer Morphology and Dispersibility on Mechanical Properties and Electrical Conductivity of Solution-cast PANI-DBSA/HIPS Blends
Lee, Jong-Hyeok ; Choi, Sun-Woong ; Kim, Eun-Ok ;
Polymer Korea, volume 35, issue 6, 2011, Pages 543~547
A study has been done to enhance the mechanical properties and processability of electrically conductive polyaniline(PANI) without the polymer's structural alternation. Functionalized acid doped PANI (PANI-DBSA) was prepared by an emulsion polymerization, and dodecylbenzenesulfonic acid (DBSA) played both roles of surfactant and dopant. Also, PANI-DBSA was solution cast blended with high impact polystyrene (HIPS) to produce PANI-DBSA/HIPS blend film. The structure and electrical properties of the conducting polymer blends were observed through UV-vis and FTIR/ATR spectroscopy. A study of the blend was carried by focusing on observation of mechanical and electrical properties based on dispersibility and changes in polymer morphology. The conductivity of the blends was increased by increasing the content of PANI-DBSA, and the sudden increase of conductivity to
S/cm was observed even under a low content of 9 wt%. There was a strong association of continuous network formation with percolation and conductivity in the conducting polymer blends.
Influence of Alkylation on Interface and Thermal Conductivity of Multi-walled Carbon Nanotubes-reinforced Epoxy Resin
Heo, Gun-Young ; Rhee, Kyong-Yop ; Park, Soo-Jin ;
Polymer Korea, volume 35, issue 6, 2011, Pages 548~552
Two functionalization methods, i.e., acid treatment and chemical amidation were performed to prepare the functionalized multi-walled carbon nanotubes (MWCNT), and the properties of epoxy/functionalized MWCNT composites were investigated and compared. Fourier transform infrared spectroscopy (FTIR) was used to confirm the surface functionality of the MWCNT obtained by the functionalization methods. The effects of the MWCNT functionalization on the interface and thermal conductivity were studied by zeta potential analyzer, scanning electron microscope and thermal conductivity analyzer. From these results, it was confirmed that the thermal conductivity of the epoxy/MWCNT composites could be increased by grafting with dodecylamine. This could be interpreted by relatively strong dispersion forces of the grafting MWCNT with dodecylamine in DGEBF epoxy resin. These results were in good agreement with the results that the zeta potential value of the grafting MWCNT with dodecylamine has a higher negative value than that of MWCNT with acid treatment.
Electrospinning Fabrication and Characterization of Poly(vinyl alcohol)/Waterborne Polyurethane/Montmorillonite Nanocomposite Nanofibers
Kim, In-Kyo ; Yeum, Jeong-Hyun ;
Polymer Korea, volume 35, issue 6, 2011, Pages 553~557
Poly(vinyl alcohol) (PVA)/waterborne polyurethane (WBPU)/montmorillonite clay (MMT) nanocomposite nanofibers were prepared using electrospinning technique of aqueous solutions. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction and thermal gravimetric analyzer were used to characterize the morphology and properties of the nanocomposite nanofibers. Since PVA, WBPU and MMT are hydrophilic, non-toxic and biocompatible materials, these nanocomposite nanofibers can be used for filter and medical industries as wound dressing materials, antimicrobial filters, etc.
Preparation and Properties of Biodegradable Superabsorbent Gels Based on Poly(aspartic acid)s with Amino Acid Pendants
Son, Chang-Mo ; Jeon, Young-Sil ; Kim, Ji-Heung ;
Polymer Korea, volume 35, issue 6, 2011, Pages 558~564
The biocompatibility and biodegradability of poly(amino acid) make them ideal candidates for many bio-related applications. Poly(aspartic acid), PASP, is one of synthetic water-soluble polymers with proteinlike structure, and has been extensively explored for the potential industrial and biomedical applications due to its biodegradable, biocompatible and pH-responsive properties. In this work, amino acid-conjugated PASPs were prepared by aminolysis reaction onto polysuccinimide (PSI) using
-aminobutylic acid(GABA) and
-alanine methyl ester and a subsequent hydrolysis process. Their chemical gels were prepared by crosslinking reaction with ethylene glycol diglycidyl ether (EGDE). The hydrogels were investigated for their basic swelling behavior, hydrolytic degradation and morphology. The crosslinked gels showed a responsive swelling behavior, which was dependent on pH and salt concentration in aqueous solution, and relatively fast hydrolytic degradation.
Effects of Oxygen Plasma-treated Graphene Oxide on Mechanical Properties of PMMA/Aluminum Hydroxide Composites
Kim, Hyo-Chul ; Jeon, Son-Yeo ; Kim, Hyung-Il ; Choi, Ho-Suk ; Hong, Min-Hyuk ; Choi, Ki-Seop ;
Polymer Korea, volume 35, issue 6, 2011, Pages 565~573
The nanocomposites containing graphene oxide (GO) were prepared in order to improve the mechanical properties of poly(methyl methacrylate)/aluminum hydroxide (PMMA/AH) composites. GO was prepared from graphite by oxidation of Hummers method followed by exfoliation with thermal treatment. The surface of GO was modified by oxygen plasma in various exposure times from 0 to 70 min to improve interfacial compatibility. Compared with PMMA/AH composites, the nanocomposites containing GO modified with oxygen plasma for the exposure time up to 50 min showed significant increases in flexural strength, flexural modulus, Rockwell hardness, Barcol hardness, and Izod impact strength. The morphology of fracture surface showed an improved interfacial adhesion between PMMA/AH composites and GO, which was properly treated with oxygen plasma. The mechanical properties of nanocomposites were deteriorated by increasing the content of GO above 0.07 phr due to the nonuniform dispersion of GO.
Dynamics and Instability of a Polymeric Paint in Roll Coating Process for Automotive Pre-coating Application
Kim, Jin-Ho ; Lee, In-Jun ; Noh, Seung-Man ; Kang, Choong-Yeol ; Nam, Joon-Hyun ; Jung, Hyun-Wook ; Park, Jong-Myung ;
Polymer Korea, volume 35, issue 6, 2011, Pages 574~579
3-Roll coating process as a key application technology for manufacturing automotive pre-painted metal-sheets has been studied. The 3-Roll coating system for this study consists of pick-up roll for picking up and distributing coating liquid from the reservoir, metering roll to properly meter coating liquid in metering gap regime, and applicator roll for directly transferring liquid into metal-sheet surface. Flow dynamics and operable coating windows of a polymeric paint (primer) with shear-thinning rheological property have been correlated with processing parameters such as speed ratio and metering gap between pick-up and metering rolls. In the uniform coating regime, dry coating thickness increased with increasing metering gap or decreasing speed ratio. Ribbing and cascade instabilities were observed in low speed and high speed ratio conditions, respectively. It is revealed that lower speed ratio makes severity and wavelength of the ribbing increase, aggravating flow instability in coating systems.
Characteristics of Biodegradable Blends of PBAST and Chemically Modified Thermoplastic Starch
Shin, Boo-Young ;
Polymer Korea, volume 35, issue 6, 2011, Pages 580~585
This article aims to enhance the biodegradability and environment-friendliness of petroleum based biodegradable poly(butylene adipate-co-succinate-co-terephthalate)(PBAST) by blending chemically modified thermoplastic starch(CMPS). CMPS is a kind of bio-based biodegradable resin which is manufactured by reacting starch with maleic anhydride(MA) in the presence of a plasticizer and a free radical initiator. The characteristic properties of PBAST/CMPS blends were investigated by observing their morphology, thermal, mechanical properties, and biodegradability. The good interfacial adhesion between the phases examined by SEM revealed that PBAST/CMPS blends were compatible blends. The tensile strength and elongation decreased with increasing CMPS content, while modulus increased. The biodegradability of the blends was much higher than that of pristine PBAST and increased with increasing CMPS contents.
Synthesis and Characterization of Vinylbenzyl Chloride-co-Styrene-co-Hydroxyethyl Acrylate (VBC-co-St-co-HEA) Anion-Exchange Membrane for All-Vanadium Redox Flow Battery
Baek, Young-Min ; Kwak, Noh-Seok ; Hwang, Taek-Sung ;
Polymer Korea, volume 35, issue 6, 2011, Pages 586~592
In this study, we synthesized vinylbenzyl chloride-co-styrene-co hydroxyethyl acrylate (VBC-co-St-co-HEA) copolymer that can be applied to redox the flow battery process. The anion exchange membrane was prepared by the amination and crosslinking of VBC-co-St-co-HEA copolymer. The chemical structure and thermal properties of VBC-co-St-co-HEA copolymer and aminated VBC-co-St-co-HEA(AVSH) membrane were characterized by FTIR,
NMR, TGA, and GPC analysis. The membrane properties such as ion exchange capacity(IEC), electrical resistance, ion conductivity and efficiency of all-vanadium redox flow battery were measured. The IEC value, electrical resistance, and ion conductivity were 1.17 meq/g,
, 0.009 S/cm, respectively. The charge-discharge efficiency, voltage efficiency and energy efficiency from all-vanadium redox flow battery test were 99.5, 72.6 and 72.1%, respectively.
Synthesis and Characterization of IPA-co-HDO-co-(TPA/MA) Anion-Exchange Membrane for All-Vanadium Redox Flow Battery
Jung, Jae-Chul ; Kwak, Noh-Seok ; Hwang, Taek-Sung ;
Polymer Korea, volume 35, issue 6, 2011, Pages 593~598
The IPA-co-HDO-co-(TPA/MA) copolymers for all-vanadium redox flow battery were synthesized by melt condensation polymerization using isophthalic acid(IPA), 1,6-hexandiol (HDO), terephthalic acid(TPA) and maleic anhydride(MA). The amination of chloromethylated IPA-co- HDO-co-(TPA/MA)(CIHTM) copolymer was carried out using trimethylamine, and the anion exchange membrane was also prepared by UV crosslinking reaction. The structure and thermal stability of IHTM copolymers were confirmed by FTIR,
NMR, and TGA analysis. The anion membrane properties such as water uptake, ion exchange capacity, electric resistance and electrical conductivity, were measured by gravimetry, titration and LCR meter. The efficiency of the all-vanadium redox flow battery was analyzed. The ion exchange capacity, electric resistance and electrical conductivity were 1.10 meq/g,
, and 0.009 S/cm, respectively. The efficiency of charge-discharge, voltage, and energy for the allvanadium redox flow battery were 96.5, 74.6, 70.0%, respectively.
Characteristics of PET-PEN Copolymer as a Material for Flexible Substrate
Youm, Joo-Sun ; Kim, Jea-Hyun ; Kang, Ho-Jong ;
Polymer Korea, volume 35, issue 6, 2011, Pages 599~604
The PET-PEN copolymers have been synthesized and the effect of their morphology on the physical properties of polyester flexible substrate was investigated. It was found that the block sequence of synthesized copolymer was varied depending upon DMT/NDC ratio in polymerization. Higher PET-PEN and PEN block sequence in polyester copolymer resulted in the increase of glass transition temperature and it caused the enhancement of dimensional stability as a polyester flexible substrate. The highest coefficient of thermal expansion(CTE) was obtained when DMT/NDC ratio is 50/50. Synthesized PET-PEN copolymer seems to be acceptable as a flexible substrate since it shows that their optical transmittance at 550 nm is over 80% and thermal weight loss at
for 1 hr is less than 0.4 wt%.
Characteristic Change of PVDF-
Composite Nanofibers with Different Thermal Treatment Temperature
Kim, Young-Jin ;
Polymer Korea, volume 35, issue 6, 2011, Pages 605~609
Composite nanofibers were prepared by electrospinning and thermal treatment from poly (vinylidene fluoride) (PVDF)-
blend solution. The nanofibers were stacked on layers to produce fully interconnected pores. TEM micrographs and EDX spectra confirmed the presence of
in the composite nanofibers. The porosity of nanofibers was effectively enhanced by the introduction of electrospinning technique. ATR-FTIR and XRD results revealed that PVDF in the composite nanofibers exhibited the mixture crystal structure of
-phase. The crystal structure of
-phase and crystallinity increased by the thermal treatment. In addition, the mechanical properties, thermal stability and hydrophobicity were markedly amplified by the thermal treatment.
Evaluation of the Effect of Solvent on the Preparation of PVBC-g-ETFE Film by a Pre-irradiation Method
Lee, Sun-Young ; Song, Ju-Myung ; Sohn, Joon-Yong ; Nho, Young-Chang ; Shin, Jun-Hwa ;
Polymer Korea, volume 35, issue 6, 2011, Pages 610~614
In this study, the effect of solvent on the pre-irradiation grafting of VBC(vinylbenzyl chloride) onto a ETFE(polyethylene-co-tetrafluoroethylene) was evaluated. ETFE film was irradiated to generate radical species onto its backbone chain. Each irradiated film was immersed into VBC monomer mixtures diluted with various solvents such as toluene, heptane, and isopropanol etc. for grafting process and then the degree of grafting of each film was measured. FTIR analysis confirmed that the VBC-g-ETFE film was successful prepared. For the films prepared in the various solvents, the mechanical strength and the distribution pattern of the graft polymer over the cross-section of the films were measured and the effect of solvent was evaluated.
Use of Amphiphilic Graft Copolymer as Dispersant for Carbon Nanotubes
Jeon, Ha-Rim ; Ahn, Sung-Hoon ; Chi, Won-Seok ; Kim, Jong-Hak ;
Polymer Korea, volume 35, issue 6, 2011, Pages 615~618
Carbon nanotubes (CNTs) draw attention as promising materials due to their excellent electrical and mechanical properties. However, the intrinsic strong interaction between CNTs presents a challenge to their use in various applications. Here, we present a facile method to disperse single-walled carbon nanotubes (SWCNTs) in a polar solution using a graft copolymer, poly(vinyl chloride)-graft-poly(oxyethylene methacrylate), PVC-g-POEM. The graft copolymer was synthesized via atom transfer radical polymerization (ATRP), as confirmed by gel permeation chromatography (GPC) and
NMR spectroscopy. The SWCNTs were uniformly dispersed in a polar solvent such as dimethylsiloxane (DMSO) using PVC-g-POEM as a dispersant, due to interaction between CNT and the graft copolymer, as revealed by transmission electron microscopy (TEM) analysis. Upon removal of the solvent, free standing nanocomposite films with good homogeneity were obtained.