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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 36, Issue 6 - Nov 2012
Volume 36, Issue 5 - Sep 2012
Volume 36, Issue 4 - Jul 2012
Volume 36, Issue 3 - May 2012
Volume 36, Issue 2 - Mar 2012
Volume 36, Issue 1 - Jan 2012
Selecting the target year
Adhesion Mechanism of Polyurethane Adhesive for Laminated Steel Plate
Youm, Joo-Sun ; Kang, Ho-Jong ;
Polymer Korea, volume 36, issue 2, 2012, Pages 119~123
DOI : 10.7317/pk.2012.36.2.119
Adhesion strength of polyurethane adhesive for laminated metal plate was investigated. Also, the effect of laminating conditions on the adhesion strength was understood by measuring peel strength as a function of adhesion temperature and time. The amount of isocyanate appearing due to the unblocking of oxime in polyurethane adhesive affected the strength of adhesion with hydroxyl on the metal plate or aluminum foil and it was controlled by adhesion temperature and time. However, the excess of temperature and time in laminating process caused the lowering of adhesion strength because of the decrease of solvent content as well as thermal degradation of the adhesive.
Characteristics and Biocompatibility of Electrospun Nanofibers with Poly(L-lactide-co-ε-caprolactone)/Marine Collagen
Kim, Woo-Jin ; Shin, Young-Min ; Park, Jong-Seok ; Gwon, Hui-Jeong ; Kim, Yong-Soo ; Shin, Heung-Soo ; Nho, Young-Chang ; Lim, Youn-Mook ; Chong, Moo-Sang ;
Polymer Korea, volume 36, issue 2, 2012, Pages 124~130
DOI : 10.7317/pk.2012.36.2.124
The uniform nanofibers of poly(L-lactide-
-caprolactone) (PLCL) with different contents of marine collagen (MC) were successfully prepared by electrospinning method. The effects of the major parameters in electrospinning process such as tip to target distance (TTD), voltage, nozzle size and flow rate on the average diameter of the electrospun nanofiber were investigated in generating composite nanofiber. The diameter and morphology of the nanofibers were confirmed by a scanning electron microscopy (SEM). Also, we measured a water contact angle to determine the surface wettability of the nanofibers. The average diameter of the nanofibers decreased as the value of TTD, MC contents, and voltages increased in comparison with that of pristine PLCL nanofiber. In contrast, the diameter of the nanofibers increased as the flow rate and inner diameter of nozzle increased in comparison with that of pristine PLCL. In addition, the hydrophilicity of the nanofiber and attachment of MG-63 cells on the sheets increased as incorporated collagen contents increased. Therefore, the marine collagen would be a potential material to enhance cellular interactivity of synthetic materials by mimicking the natural tissue.
Investigation on the Residual Stress Relaxation according to Annealing Condition for Transparent Injection Molded Part
Cho, Jeong-Hyun ; Park, Seo-Ri ; Kim, Hyeok ; Lyu, Min-Young ;
Polymer Korea, volume 36, issue 2, 2012, Pages 131~136
DOI : 10.7317/pk.2012.36.2.131
Residual stress is developed in the injection molded articles during the molding process due to temperature variation and shear stress. The residual stress causes the deformation and warpage in the injection molded parts shortly within several days or after several years. Therefore, the injection molding conditions should be optimized to reduce the residual stress. And residual stress in the part should be also relaxed after molding process to maintain its shape. According to the annealing conditions, such as relative humidity, temperature and time, this study investigates the relaxation of residual stress generated in the transparent injection molded specimens. Through the experimental results, it was realized that the residual stress was relaxed at a relative humidity higher than 50%. Utilizing photoelasticity equipment, it was found that the residual stress was rapidly relaxed near glass transition temperature. Additionally, we recognized that the specimen shrunk along the flow direction but expanded to the perpendicular direction of the flow during the annealing processes, which resulted in the warpage of the specimen.
Plasma-induced Graft Copolymerization of Glycidyl Methacrylate on the Surface of Polyethylene
Kim, Ji-Eun ; Liu, Xuyan ; Choi, Ho-Suk ; Kim, Jae-Ha ; Park, Han-Oh ;
Polymer Korea, volume 36, issue 2, 2012, Pages 137~144
DOI : 10.7317/pk.2012.36.2.137
The surface of polyethylene (PE) was modified through Ar atmospheric pressure plasma treatment and subsequent grafting of glycidyl methacrylate (GMA). Optimum plasma treatment conditions were determined through analyzing the surface free energies calculated from the contact angles between PE samples and three probe liquids, which were RF-power of 200 W, plasma treatment time of 600 sec, Ar flow rate of 5 LPM, and sample-holder moving speed of 20 mm/sec. To introduce the maximum amount of GMA on PE surface treated under the conditions, graft copolymerization conditions such as GMA concentration, temperature, and time were carefully controlled. Grafting degree (GD) was obtained through weight difference analysis of PE film before and after graft copolymerization. A maximum GD was achieved at the GMA concentration of 20 vol%, the temperature of
, and the treatment time of 4 hr.
Effects of UV Irradiation and Thermal Treatment of Photo-Degradable Polyimide Layer on LC Alignment
Lee, Jang-Ju ; Lee, Won-Ho ; Shin, Yong-Il ; Paek, Sang-Hyon ;
Polymer Korea, volume 36, issue 2, 2012, Pages 145~148
DOI : 10.7317/pk.2012.36.2.145
The effects of the linearly polarized UV (LPUV) irradiation and thermal treatment of a photo-degradable polyimide (CBDA-ODA) alignment layer (AL) on its AL properties, liquid crystal (LC) alignment, and LCD characteristics have been investigated. The best quality of LC photo-alignment have been induced by the LPUV-irradiation with much (about 5~10 times) less dosage than that generating the maximum anisotropy of the AL. A thermal treatment of the LPUV-irradiated AL has effectively removed the undesirable, low-M.W. fragments of the AL generated during the photo-decomposition and increased the stability of the AL, which has resulted in improvement of the LC alignment and the LCD property.
Lipoic Acid Conjugated Chitosan Copolymer for the Delivery of 5-Fluorouracil
Lee, Sun-Young ; Kim, Young-Jin ;
Polymer Korea, volume 36, issue 2, 2012, Pages 149~154
DOI : 10.7317/pk.2012.36.2.149
The amphiphilic copolymer by the conjugation of biocompatible chitosan and antioxidant lipoic acid was studied as a drug delivery carrier. The amphiphilic copolymer was self-assembled to form nanoparticles in the aqueous solution. 5-Fluorouracil widely used as an anticancer drug was encapsulated inside the nanoparticles by a solid dispersion method. The degree of branching of lipoic acid on chitosan was controlled to obtain the optimal condition for the drug delivery carrier. The sizes of nanoparticles were about 250 nm by the dynamic light scattering. The encapsulation efficiency of nanoparticles were about 10%. The copolymer with 42% degree of branching showed the best performance as a drug delivery carrier.
Preparation and Properties of Sulfonated Poly(ether ether ketone) (SPEEK) Electrospun Nanofibrous Ion-exchange Membrane for PEMFC
Kwak, Noh-Seok ; Choi, Eun-Jung ; Hwang, Taek-Sung ;
Polymer Korea, volume 36, issue 2, 2012, Pages 155~162
DOI : 10.7317/pk.2012.36.2.155
Sulfonated poly(ether ether ketone) (SPEEK) nanofibers were prepared by electrospinning. The nanofibrous membrane for polymer electrolyte membrane fuel cell (PEMFC) was fabricated by compression molding. The maximum degree of sulfonation was 95% and the initial thermal degradation temperature was
and it's value was lower than that of PEEK. The contact angle of SPEEK increased with decreasing the degree of sulfonation. The optimum voltage, flow rate, tip to collector distance (TCD) and concentration of electrospinning conditions were 22 kV, 0.3 mL/hr, 15 cm, and 23 wt%, respectively. The average nanofibrous diameter was 47.6 nm. The water uptake and ion exchange capacity of SPEEK nanofibrous membrane increased with increasing the sulfonation time and the amount of sulfonating agent. The electrical resistance and proton ionic conductivity of SPEEK membrane increased with decreasing and increasing the sulfonation time, respectively. Their values were 0.58~0.06
and 0.099 S/cm.
Development of Drug Eluting Stent for the Treatment of Benign Biliary Stricture by Electro-spray Method
Shin, Il-Gyun ; Kim, Dong-Gon ; Kim, Han-Ki ; Kim, Sang-Ho ; Jeon, Dong-Min ; Suh, Tae-Seok ; Jang, Hong-Seok ;
Polymer Korea, volume 36, issue 2, 2012, Pages 163~168
DOI : 10.7317/pk.2012.36.2.163
Recently, along with technology development of endoscopic equipment, the stent technology has been developed for the convenience of operation, shortening of recovery times, and reduction of patient's pain. In this study, paclitaxel-eluting metal stents for treatment of biliary benign stenosis were developed through an electrospray-coating method. Polyether-based polyurethane (PELLETHANE 2363-80AE
)) and paclitaxel were coated onto the surface of a metallic stent and Pluronic F127 was used as an additive. As a result, physicochemical characterization of paclitaxel via SEM, FTIR, contact angle and XRD techniques revealed the information of solid state of paclitaxel-loaded PU film. The in vitro release profile showed a slower release rate with a higher content of paclitaxel.
The Effect of Electrode Pattern on the Humidity-sensing Properties of the Resistive Humidity Sensor Based on All-printing Process
Ahn, Hee-Yong ; Gong, Myoung-Seon ;
Polymer Korea, volume 36, issue 2, 2012, Pages 169~176
DOI : 10.7317/pk.2012.36.2.169
Based on our experience in developing resistive humidity sensor, interdigital gold electrodes with different fingers and gaps have been fabricated on a glass epoxy (GE) substrate using screen printing techniques. The basic structure of the electrode consisted of a 3-, 4- and 5-fingers with gaps of 310 and 460
. Gold electrode/GE was prepared by first printing silver nanopaste, followed by consecutive electroless plating of Cu, Ni and then Au. Copolymer of [2-(methacryloyloxy)ethyl] dimethyl benzyl ammonium chloride (MDBAC) and methyl methacrylate (MMA) was used as a humidity-sensing polyelectrolyte, which was fabricated by a screen printing method on the Au electrode/GE substrate. The flexible humidity sensor showed acceptable linearity between logarithmic impedance and relative humidity in the range of 20-95%RH, low hysteresis of 1.5%RH, good response and recovery time of 75 sec at 1 V, 1 kHz, and
. Electrode construction had a significant influence on the humidity-sensing characteristics of polymeric humidity sensors. The activation energy between electrode and ion conducting polyelectrolyte plays an important role in explaining the differences of humidity sensing characteristics such as temperature dependence, sensitivity, linearity and hysteresis.
In situ Microfluidic Method for the Generation of Monodisperse Double Emulsions
Hwang, So-Ra ; Choi, Chang-Hyung ; Kim, Hui-Chan ; Kim, In-Ho ; Lee, Chang-Soo ;
Polymer Korea, volume 36, issue 2, 2012, Pages 177~181
DOI : 10.7317/pk.2012.36.2.177
This study presents the preparation of double emulsions in a poly(dimethylsiloxane) (PDMS)-based microfluidic device. To improve the wettability of hydrophilic continuous phase onto a hydrophobic PDMS microchannel, the surface was modified with 3-(trimethoxysilyl) propyl methacrylate (TPM) and then sequentially reacted with acrylic acid monomer solution, which produced selective covalent bonding between acrylic acids and methacrylate groups. For the proof of selective surface modification, tolonium chloride solution was used to identify the modified region and we confirmed that the approach was successfully performed. When water containing 0.5% w/w sodium dodecyl sulfate and 1% w/w Span80 with hexadecane were loaded into the selectively modified microfluidic channels, we can produce stable double emulsion. Based on the spreading coefficients, we predict the morphology of double emulsions. Our proposed method efficiently produces monodisperse double emulsions having 48.5
(CV:1.6%) core and 65.1
(CV:1.6%) shell. Furthermore, the multiple emulsions having different numbers of core were easily prepared by simple control of flow rates.
Preparation of Poloxamer-based Hydrogels Using Electron Beam and Their Evaluation for Buccal Mucoadhesive Drug Delivery
Baek, Eun-Jung ; Shin, Baek-Ki ; Nho, Young-Chang ; Lim, Youn-Mook ; Park, Jong-Seok ; Park, Jeong-Sook ; Huh, Kang-Moo ;
Polymer Korea, volume 36, issue 2, 2012, Pages 182~189
DOI : 10.7317/pk.2012.36.2.182
In this study, poloxamer hydrogels were prepared by electron beam irradiation and evaluated for potential application as a buccal mucoadhesive drug delivery system. Poloxamer, one of typical thermoresponsive polymers, was modified to have vinyl end groups for crosslinking reaction, and its hydrogels were fabricated by irradiation crosslinking reaction. Carbopol as a mucoadhesive polymeric additive was introduced to improve the mucoadhesive property of the hydrogels and its effect on the mucoadhesion and drug release properties was investigated. The results showed that the end group modification of poloxamer and the addition of carbopol improved mucoadhesive force and mechanical properties and led to a sustained drug release behavior.
Interfacial and Rheological Properties of Selected Hydrogel Formulations for Soft Contact Lens
Noh, Hye-Ran ;
Polymer Korea, volume 36, issue 2, 2012, Pages 190~195
DOI : 10.7317/pk.2012.36.2.190
Interfacial and rheological properties of selected hydrogel formulations were studied to understand the contact-lens comfort in end use. It was concluded that protein adsorption from aqueous solution decreased monotonically with increasing surface energy (water wettability) of tested hydrogels. Also, it has revealed that friction coefficient of polydimethylsiloxane-polyvinylpyrrolidone (PDMS-PVP) was significantly larger that 2-hydroxyethyl methacrylate (HEMA) based hydrogels. Interestingly, in artificial tear solution, friction coefficients of HEMA based hydrogels were larger than silicone hydrogels.
Preparation and Characterization of Electrospun Pullulan Webs
Son, Tae-Won ; Lee, Gun-Min ; Lee, Dong-Won ; Lee, Ju-Hyun ; Lim, Hak-Sang ;
Polymer Korea, volume 36, issue 2, 2012, Pages 196~201
DOI : 10.7317/pk.2012.36.2.196
Electrospinning is a versatile process used to prepare micro or nano sized fibers from various materials dissolved in volatile solvents. This study reports electrospun pullulan fibrous webs fabricated through electrospinning using water as a solvent. The electrospinning conditions such as pullulan (PUL) concentration and applied voltage were optimized in order to obtain smooth electrospun fibers. The concentration of PUL greatly influenced the viscosity and surface tension of PUL solution. PUL beaded electrospun fibers were obtained from PUL solutions with concentrations lower than 5 wt%, while homogenous electrospun fibers were prepared from solutions with high concentration and high viscosity. The average diameters of PUL fibers were decreased to 200 nm when the polymer concentration was kept at 10 wt% and the applied voltage was fixed at 15 kV during electrospinning. PUL electrospun fiber exhibited higher solubility, flexibility, softness and adhesive strength.
Preparation and Characteristics of Poly(ε-caprolactone) Microcapsules Containing Pseudomonas by W/O/W Emulsion
Kim, Ki-Seok ; Lee, Seung-Yeop ; Lee, Gun-Woong ; Kim, Hyung-Gon ; Park, Soo-Jin ;
Polymer Korea, volume 36, issue 2, 2012, Pages 202~207
DOI : 10.7317/pk.2012.36.2.202
-caprolactone)(PCL) microcapsules containing pseudomonas were prepared by W/O/W emulsion system. The characteristics and release behaviors of the microcapsules were investigated as a function of manufacturing conditions. The morphology and particle distribution of the microcapsules were observed by a scanning electron microscope and a particle size analyzer. The release behaviors of the pseudomonas were determined using a cell culture method. It was found that smooth and spherical microcapsules were formed by W/O/W emulsion system and particle size was in the range of 10 to 60
. The release behaviors of the pseudomonas were influenced by the manufacturing conditions. It was indicated that the increase of the surfactant content and stirring rate led to an increased release rate, resulting from the high specific surface area of the smaller particle size, and the increase of the PCL content provided the sustained release behaviors by the delay effect of diffusion in the release medium.
Studies on the Strength of Cement Mortars with Surface Crosslinked cPSA Absorbent
Hwang, Ki-Seob ; Jang, Seok-Soo ; Jung, Yong-Wook ; Lee, Seung-Han ; Ha, Ki-Ryong ;
Polymer Korea, volume 36, issue 2, 2012, Pages 208~215
DOI : 10.7317/pk.2012.36.2.208
To study the effect of surface crosslinked layer on the crosslinked poly(sodium acrylate) (cPSA) absorbent, we synthesized several surface crosslinked cPSAs with 5, 10 and 20 g of ethylene glycol dimethacrylate (EGDMA) by an inverse emulsion polymerization method to delay the absorption of excess water in concrete. We measured the compressive and flexural strength of mortars having 0.5, 1.0 and 1.5 wt% cPSA-EGDMA. We observed the increase of compressive and flexural strength of the cPSA-EGDMA added cement mortars except for the 0.5 wt% cPSA-EGDMA (20 g) added cement mortar. 1.0 wt% cPSA-EGDMA (5 g) added cement mortar showed about 16% and 10% increased compressive and flexural strength than those of plain cement mortar. To study the effect of porosity on compressive and flexural strength, we used FE-SEM and porosimeter. FE-SEM analysis showed swollen cPSMAEGDMA (5 g) filled between calcium silicate hydrate (C-S-H) crystals. We observed the decreased porosity of the cPSA-EGDMA added cement mortars than that of plain cement mortar. 1.0 wt% cPSA-EGDMA (5 g) cement mortar showed the lowest porosity of 16.5%.
Synthesis and Application of cPSMA-PSMA Microcapsule Absorbent for Cement Mortars
Hwang, Ki-Seob ; Jang, Seok-Soo ; Jung, Yong-Wook ; Lee, Seung-Han ; Ha, Ki-Ryong ;
Polymer Korea, volume 36, issue 2, 2012, Pages 216~222
DOI : 10.7317/pk.2012.36.2.216
We synthesized microcapsule absorbent with crosslinked poly(styrene-
-maleic anhydride) (PSMA) as a core and PSMA as a shell by a precipitation polymerization method for the delayed absorption of excess water in cement mortar. cPSMA-PSMAs with core-shell structure were synthesized with ratios of 1/1, 1/2 and 1/3 as core monomer mass to shell monomer mass to control shell thickness. We observed the hydrolysis of PSMA in cement-saturated aqueous solution by a FTIR spectrometer. We observed good core-shell structure microcapsules for 1/2(cPSMA #3), but observed incomplete core-shell structure for 1/1(cPSMA #2) and 1/3(cPSMA #4) of core/shell monomer ratios. The swelling ratio of cPSMA #3 in cement-saturated aqueous solution was increased until 20 min. After that it was decreased until 2 hrs swelling time, and they started to increase again. The viscosities of cement paste with cPSMA #3 microcapsules were very slowly increased until 1 hr and increased fast after 1.5 hrs. Cement mortar with 0.5 wt% cPSMA #1 having only core part showed about 5% increase in compressive strength compared to that of plain cement mortar. cPSMA #3 added cement mortar showed the highest compressive strength with 7% increase.
Synthesis and Characterization of Temperature and pH Sensitive Graft Copolymers Based on Pluronic
Oh, Yeon-Jeong ; Lee, Gi-Baek ; Park, Sung-Young ;
Polymer Korea, volume 36, issue 2, 2012, Pages 223~228
DOI : 10.7317/pk.2012.36.2.223
Temperature and pH sensitive graft copolymers [Pluronic-
-MMA), Polymer A] and [Pluronic-
-MAA), Polymer C] were synthesized by macro radical graft polymerization with
-diethylaminoethylmethacrylate (DEAEMA) and
-isopropylacrylamide (NIPAAm)/methacrylic acid (MAA) based on Pluronic, respectively. The chemical structure and molecular weight of the graft copolymers was characterized by
NMR and gel permeation chromatography. The aqueous solution properties of graft copolymers were measured using a UV-visible spectrophotometer, contact angle and dynamic light scattering equipment with different temperature and pH conditions. The obtained graft copolymers showed a very sensitive phase transition in response to temperature and pH in aqueous media which suggested that the amine group of DEAEMA segment and carboxylic group of MAA had a great influence on the lower critical solution temperatures (LCST) in Polymer A and C, respectively. The graft copolymers can be utilized for drug delivery system and molecular switching applications where responses to temperature and pH changes are relevant.
Empirical Study on the Effects of the Content and the Orientation of the Disk Shape Fillers on the Modulus of PP Composites
Seo, Sang-Bum ; Lee, Yong-Hyun ; Jeoung, Sun-Kyoung ; Lee, Seung-Goo ; Lee, Kee-Yoon ;
Polymer Korea, volume 36, issue 2, 2012, Pages 229~234
DOI : 10.7317/pk.2012.36.2.229
This paper studied the effects of the content and the orientation of the disk shape fillers on the modulus of PP composites. The experimental results were compared with the theoretical calculations which included the three dimensional ellipsoids and analyzed by two aspect ratios,
proposed by Lee and his researchers. Mica and talc were used as disk shape fillers in the composites. The shapes of mica and talc were observed by SEM and aspect ratios were statistically calculated. For the case of mica, the average aspect ratios were
, and for the case of talc, they were
. Also, the effects of two aspect ratios and the content of filler on the mechanical properties were studied: For 30 wt% of mica,
increased up to about 2.7 times, and for the other case of talc,
increased up to about 2.3 times, respectively.
Thiazole Type Accelerator Effects on Silane/Silica Filled Natural Rubber Compound upon Vulcanization and Mechanical Properties
Kim, Sung-Min ; Kim, Kwang-Jea ;
Polymer Korea, volume 36, issue 2, 2012, Pages 235~244
DOI : 10.7317/pk.2012.36.2.235
A thiazole type accelerator MBT (2-mercapto benzothiazole) was added into silica filled natural rubber (NR) compound with various concentrations (0, 1, 2, 3, 4 phr). The effects of MBT on the cure rate, mechanical property, degree of rubber-filler interaction (
), crosslinking density, and viscoelastic property (
) were investigated. As accelerator concentration increased, the
decreased and the crosslinking density and modulus at 300% elongation increased. The tensile strength and elongation increased up to 3 phr and no further increased at 4 phr. The
value measured at room temperature was higher than that of the
value was not affected by the addition of MBT. The mechanisms for the vulcanization rate were reviewed.
Study on the Non-isothermal Crystallization Kinetics of Branched Polypropylene
Yoon, Kyung-Hwa ; Shin, Dong-Yup ; Kim, Youn-Cheol ;
Polymer Korea, volume 36, issue 2, 2012, Pages 245~250
DOI : 10.7317/pk.2012.36.2.245
Branched polypropylenes (PP) with long chain branch were prepared by solid state reaction with three different branching agent of 0.3 wt% content. The chemical structures, non-isothermal crystallization behavior and complex viscosity of the branched PP were investigated by FTIR, DSC, optical microscope, and dynamic rheological measurement. The chemical structure of the branched PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100
. There was no distinct change in melting temperature in case of PP-D-0-3 and PP-F-0-3, but PP-H-0-3 indicated a decrease in melting temperature. The decrease in melting temperature was interpreted by the fact that the degradation reaction of PP was more dominant than branched reaction, and confirmed by a decrease in complex viscosity. The non-isothermal crystallization behavior of the branched PP was analyzed using by Avrami equation. The Avrami exponent of PP was 3, and the values of the branched PP with DVB and FS were below 3. The activation energy of PP calculated by Kissinger method was 25 kJ/mol, and there were no big difference in activation energies of the branched PPs compared to PP.