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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 31, Issue 6 - Nov 2007
Volume 31, Issue 5 - Sep 2007
Volume 31, Issue 4 - Jul 2007
Volume 31, Issue 3 - May 2007
Volume 31, Issue 2 - Mar 2007
Volume 31, Issue 1 - Jan 2007
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Characteristics and Release Behaviors of Aromatic Poly(vinyl acetate) Nanoparticles Prepared by Emulsification-Diffusion Technique
Sohn, Sung-Ok ; Lee, So-Min ; Kim, Yun-Mi ; Ghim, Han-Do ;
Polymer Korea, volume 31, issue 3, 2007, Pages 177~183
In this study, nano-sized poly(vinyl acetate) (PVAc) particles containing lavender oil as a core material were prepared by using emulsification-diffusion method. Effects of experimental parameters on the characteristics and the release behavior were examined with a field emission- scanning electron microscope, an electrophoretic light scattering spectrophotometer, a visible spectrophotometer and a high performance liquid chromatography The resulting aromatic particles could be prepared in nano-sized globular shapes with the mean particle size of 224 nm by controlling the experimental conditions. From the evaluation of release properties of aromatic PVAc nanoparticles with or without PVA coating, it was found that the aromatic particles coated with PVA show more sustaining and stable release behaviors. Our research on aromatic PVAc nanoparticles could be applied for durable fragrant finishing for textiles, leather products and so on.
Electroless Ni Plating of Monodisperse Polymer Particles
Kim, Dong-Ok ; Shon, Won-Il ; Jin, Jeong-Hee ; Oh, Seok-Heon ;
Polymer Korea, volume 31, issue 3, 2007, Pages 184~188
Monodisperse PMMA/HDDA polymer particles were coated via electroless Ni plating using sodium hypophosphite as a reducing agent in an acidic environment. In this study, the effects of 1) the pretreatment conditions, 2) the plating temperature, 3) the plating pH, and 4) the initial pH, control of plating bath on the variation of plating rate, surface state of plated particles and plating reproducibility were investigated. It was observed that every pretreatment steps, especially conditioning and acceleration step, were very important for obtaining uniform Ni plating and the plating rate was increased with the increase of plating temperature and pH. Moreover, the initial pH control of plating bath was critical for the plating reproducibility.
Effect of Molecular Weight of PLGA on Release Behavior of Doxorubicin for Double-Layered PLGA Microspheres
Park, Jung-Soo ; Yang, Jae-Chan ; Yuk, Soon-Hong ; Shin, Hyung-Shik ; Rhee, John-M. ; Kim, Moon-Suk ; Lee, Hai-Bang ; Khang, Gil-Son ;
Polymer Korea, volume 31, issue 3, 2007, Pages 189~193
We developed the doxorubicin-loaded PLGA double-layered microspheres using relatively simple oil-in-water (O/W) solvent evaporation method for sustained release of doxorubicin and investigated the release behavior according to PLGA molecular weight and initial drug loading. The double-layered microsphere was characterized on the surface, the cross-section morphology, the behavior of doxorubicin release for 5 weeks by SEM and fluorescence spectrophotometer. Double-layered microspheres showed smooth surfaces and clear difference between core and outer-shell. As the PLGA molecular weight increased, the release rate of doxorubicin-loaded, double-layered microspheres decreased. These results showed that the release behaviors can be controlled by the variation of molecular weight of PLGA.
Resistive Humidity Sensor from Copolymers Containing Quaternary Ammonium Salt (I): Three Component Copolymers
Lee, Dong-Geun ; Lim, Tae-Ho ; Jeon, Young-Min ; Gong, Myoung-Seon ;
Polymer Korea, volume 31, issue 3, 2007, Pages 194~200
The resistive-type polymeric humidity sensors were prepared from the copolymers of [2- [(methacryloyloxy)ethyl] dimethyl] propylammonium bromide(MEPAB), [2- [(methacryloyloxy)ethyl]-2-hydroxyethyl]dimethylmonium bromide (MEHDAB), n-butyl methylacrylate(MBA), 2-hydroxyethyl methylacrylate(HEMA) and styrene. Four kinds of copolymers, ie, MEPAB/styrene/MEHDAB MEHDAB/BMA/HEMA, MEPAB/BMA/MEHDAB, and MEPAB/styrene/HEMA crosslinked with blocked-isocyanate on the Ag/Pd electrode/alumina substrate showed good durability at high humidities. The various electrical properties such as frequency dependency, temperature dependency, hysteresis, response time and water durability were examined. In the case of copolymer MEPAB/BMA/MEHDAB= 3/6/1, the resistance was varied from
in the range of
and this copolymers showed a good linearity and low hysteresis.
BCNU Release Behaviour from BCNU/PLGA Wafer Prepared by Vacuum Drying Method
Park, Jung-Soo ; Shin, Joon-Hyun ; Lee, Doo-Hee ; Rhee, John-M. ; Kim, Moon-Suk ; Lee, Hai-Bang ; Khang, Gil-Son ;
Polymer Korea, volume 31, issue 3, 2007, Pages 201~205
Biodegradable polymers such as polylactide, polyglycolide and poly (lactide- co-glycolide) (PLGA) have been extensively investigated because of easily controlled drug release rate, completely degradable materials without the toxic by-product, and good biocompatibility. But, according to the bulk erosion property of PLGA in vitro test, it had the disadvantage that first-order release reduced releasing amount slowly after excessive initial burst. In this study we used PLGA powder obtained through recrystallization to revise bulk erosion property of PLGA. The PLGA used in this study was prepared by vacuum drying method and to estimate release profiles of BCNU loaded PLGA wafer. We also evaluated the release profile of drug with the water soluble additive. It was found that the drug loaded PLGA recrystallized by vacuum drying method exhibited the initial burst and the constant rate of drug release compared to that prepared by a conventional method.
Study on the Coefficient of Thermal Expansion for Composites Containing 3-Dimensional Ellipsoidal Inclusions
Lee, Kee-Yoon ; Kim, Kyung-Hwan ; Jeoung, Sun-Kyoung ; Jeon, Hyoung-Jin ; Joo, Sang-Il ;
Polymer Korea, volume 31, issue 3, 2007, Pages 206~214
The theoretical study is developed for predicting the thermal expansion changes of composites which include complex inclusion, which is used three-dimensional ellipsoid model ($a_1>a_2>a_3$), which has two aspect ratios (the primary aspect ratio,
and the secondary aspect ratio,
). We can predict the feature of general thermal expansion factors by theoretical approach of matrix with aligned ellipsoidal inclusion using the Eshelby's equivalent tensor. The coefficients of longitudinal linear thermal expansion
decrease to those of inclusions,
, as both aspect ratios increase. The coefficients of transverse linear thermal expansion of composites
initially increase and show the parabolic corves with maximum values, as the concentrations of filler increase. The coefficient of thermal expansion,
in the transverse direction decreases, as
increases. The coefficient of linear thermal expansion of composites,
in the normal direction increases, as
Electrospraying of Micro/Nano Particles for Protein Drug Delivery
Yoo, Ji-Youn ; Kim, Min-Young ; Lee, Jong-Hwi ;
Polymer Korea, volume 31, issue 3, 2007, Pages 215~220
The control of the surface energy by electrohydrodynamic force provides electrospraying with various potential advantages such as simple particle size control, mono-dispersity, high recovery, and mild processing conditions. The advantages are quite helpful to improve the stability of protein drug and control its release. Herein, the nano-encapsulation of protein drugs using electrospraying was investigated. Albumin as a model protein was processed using uniaxial and co-axial electrospraying, and chitosan, polycaporlactone (PCL), and poly (ethylene glycol) (PEG) were used as encapsulation materials. The major processing parameters such as the conductivity of spraying liquids, flow rate, the distance of electrical potential gradient, etc were measured to obtain the maximum efficiency. In the chitosan systems, mean particles size decreases as flow rate and the distance between nozzle and the collecting part decreases. In the uniaxial technique of the PCL systems, mean particles size decreases as flow rate decreases. In the coaxial technique of the PCL systems, it was found that the particles size gets larger under the application of the higher ratio of inner-to-outer liquid flow rates. The primary particles formed out of an electrospraying nozzle showed narrow particle size distribution, but once they arrived to the collecting part, aggregation behavior was observed obviously. Efficient nano-encapsulation of albumin with PCL, PEG, and chitosan was conveniently achieved using electrospraying at above 12 kV.
Characterizations of Lyocell and Its Blended Nanocomposite Film: Morphology and Mechanical Property
Jang, Seo-Won ; Chang, Jin-Hae ;
Polymer Korea, volume 31, issue 3, 2007, Pages 221~227
The mechanical properties and morphologies of lyocell and its blend we compared. Poly (vinyl alcohol) (PVA) was used as a filler in blends with lyocell produced through solution blending. The variations of their properties with polymer matrix filler content are discussed. The ultimate tensile strength of the PVA/lyocell blend is highest for a blend lyocell content of 30 wt%, and decreases as the lyocell content is increased up to 40 wt%. The variations in the initial moduli of the blends with filler content are similar. Lyocell and its blended hybrid films were prepared by the solution intercalation method, using dodecyltriphenylphosphonium-mica (
-Mica) as the organoclay. The variations of the mechanical tensile properties of the hybrids with the organoclay content were examined. These properties were found to be optimal for an organoclay content of up to 5 wt%. However, the mechanical tensile properties of the PVA/Lyocell (w/w=30/70) blended hybrid films were found to decrease linearly with increases in organoclay content from 1 to 5 wt%.
Development of Medical Resorbable Composite Materials Interposed in the Poly(glycolic acid)
Lee, Chan-Woo ;
Polymer Korea, volume 31, issue 3, 2007, Pages 228~232
This purpose of this study is to enhance the hydrolysis of poly (butylene succinate-co-L-lactate) (PBSL) and poly [(R) -3-hydroxybutylate] (PHB), to develop materials with advanced medical absorbability and environmental suitability. The first method involves increasing the bioabsorbability of poly (glycolic acid) (PGA) in the core of the fibrous complex, while the second method involves making a complex fiber containing PBSL and PHB in the outer layer for improving environmental degradability Improvement in the hydrolysis of PBSL and PHB due to glycolic acid occurs by hydrolytic behavior of PGA. The drawing supporting the resulting PBSL/PGA fiber was executed at
, where the orientation is well arranged in crystal form. Obtaining a PHB/PGA complex fiber in the proper crystal orientation at
was not possible since the arranged crystal orientation was only identified in drawings from temperatures above
. Also, it is necessary to execute a smooth surface to achieve an on-line drawing since unevenness occurs in the fibrous surface from an in-line drawing.
Degradation Behavior of Medical Resorbable Composite Materials Interposed in the Poly(glycolic acid)
Lee, Chan-Woo ;
Polymer Korea, volume 31, issue 3, 2007, Pages 233~238
The purpose of the study is to apply composites of poly (glycolic acid) (PGA) with [poly(R) 3-hydroxybutyrate] (P3HB) or poly (butylenes succinate- co-L-lactate) (PBSL) as medical resorbable composite materials with the complement of hydrolysis rate of each component. As a result, it was confirmed that the PBSL/PGA and P3HB/PGA composite fiber were hydrolyzed in phosphate buffer solution. Also, it has been revealed that the degradation of PBSL/PGA are accelerated due to PGA producing glycolic acid which can act as a catalyst. In addition, the hydrolysis of PBSL/PGA was found to be accelerated by the presence of lipase PS. When the PBSL/PGA composite fiber was placed in the air, not much hydrolysis has proceeded. Also, it was confirmed that the P3HB/PGA composite fiber maintained proper tensile strength in the air. Therefore, these complex fibers can be adapted to use as environmentally suitable, medically absorbable composite materials.
Synthesis of POF Cation Exchange Fibers Using PE Coated PP Matrix by Radiation-Induced Polymerization and Their Adsorption Properties for Heavy Metals
Cho, In-Hee ; Baek, Ki-Wan ; Lim, Youn-Mook ; Nho, Young-Chang ; Hwsng, Taek-Sung ;
Polymer Korea, volume 31, issue 3, 2007, Pages 239~246
The sulfonated ion exchange fibers were synthesized by
radiation-induced graft copolymerization. Degree of grafting was increased with increasing the total dose. The degree of grafting for POF-g-St/DVB copolymer was 1000%. The ion exchange capacity of sulfonated ion exchange fibers were increased by increasing the degree of sulfonation. Its maximum value was 5.06 meq/g. The ion exchange capacity of sulfonated POF- co-St/DVB ion exchange fiber was higher than that of the sulfonated POF- co-styrene ion exchange fibers. The amount of adsorption for heavy metals were also increased with increase in the degree of grafting of the ion exchange fibers.
Preparation and Characterization of Heterogeneous Anion Exchange Membrane for Recovery of Sulfate Ion from Waste Water
Choi, Kuk-Jong ; Choi, Jae-Hwan ; Hwang, Eui-Hwan ; Rhee, Young-Woo ; Hwang, Taek-Sung ;
Polymer Korea, volume 31, issue 3, 2007, Pages 247~254
Heterogeneous anion exchange membranes were prepared by compression molding for the recovery of sulfate ion from waste water. The swelling ratio, transport number, and ion exchange capacity of the heterogeneous anion exchange membranes were increased and their electrical resistances were decreased as the amount of ion exchange resin content in the matrix was raised. The tensile strength of the heterogeneous anion exchange membrane was decreased with increasing the amount of ion exchange resin in the LLDPE. The tensile strength for the LDPE heterogeneous membrane containing 30 wt% anion exchange resin showed the highest value. The water content increased with increasing amount of ion exchange resin in the membrane. Moreover the highest transport number of the membrane was 0.86. The electrical resistance of LDPE matrix membrane with 50 wt% resin showed
. Current efficiency of electrodialysis for sulfate ion showed the highest value at the current density of
in 0.5 mol/L sulfuric acids solution.
Humidity Sensor of Polymethacrylate with 4th Ammonium Salt
Hong, Chae-Hwan ; Kim, Se-Hoon ; Nam, Byeong-Uk ;
Polymer Korea, volume 31, issue 3, 2007, Pages 255~262
In this work, two types of copolymers are manufactured by a radical polymerization to develop a material for humid membrane. Each copolymer contains three monomers that have functions to improve humid-resistance, membrane stability, flexibility, impedance, and adhesion to the electrode. MDBAB (N,N'-dimethyl-2-methacryloxyethyl-3-bromopropyl ammonium bromide) having a salt form decreases the impedance of the humid membrane and reacts with amines to produce a cross-linking structure. HEMA (2-hydroxyethyl methacrylate) has an important role which reduces the impedance and increases the adhesion strength to the electrode. The other monomers are DAEMA (N,N'-dimethylamino ethyl methacrylate), 4-VP(4-vinyl pyridine), and 2-EHA(2-ethylhexyl acrylate) and all the monomers are formulated with several compositions to make a humid membrane. At specific composition, we could attain a satisfactory results having good performance and long term durability.
Effect of Aging Time on the Sonic Conductivity of
Composite Polymer Electrolytes
Choi, Byoung-Koo ; Park, Young-Hwan ;
Polymer Korea, volume 31, issue 3, 2007, Pages 263~268
Most of current works on the PEO-salt electrolytes has been focused on the enhancement of ionic conductivity with an addition of nano-ceramic fillers, but the significant drop of the conductivity with storage time is still in question and has been frequently overlooked. The conductivity drop with aging time has been assumed to come from the incorporation of ceramic particles. However, according to authors, the reported high-temperature values of the conductivity of pure
electrolytes are nearly in agreements, but the low temperature values are in great discrepancy reaching up to 10000 times. It indicates that the conductivity at ambient temperature is greatly dependent on the thermal history and sample preparations. In this paper, we showed that the ionic conductivities of both
polymer electrolytes are strongly dependent on the thermal pretreatment and aging time. The conductivity drop with aging time of both ceramic-free and ceramic composite electrolytes has been measured to be nearly parallel. We showed that the conductivity relaxation with aging time is inherent irrespective of the incorporation of nano-ceramic fillers, since the PEO electrolytes at ambient temperature are in two-phase nature being in non-equilibrium state, never reaching completion.
Effects of Irradiation of Electron Beam on the Rheological Properties of Poly(lactic acid) and Chemically Modified Poly(lactic acid)
Shin, Boo-Young ; Kang, Kyoung-Su ; Jo, Gyu-Soon ; Han, Do-Hung ; Song, Jeong-Sup ; Lee, Sang-Il ; Lee, Tae-Jin ; Kim, Bong-Shik ;
Polymer Korea, volume 31, issue 3, 2007, Pages 269~272
In this study, we investigated the effects of electron beam irradiation on the rheological properties of PLA for enhancing processability. The electron beam was irradiated onto the pure PLA, chemically modified PLA by reactive extrusion, and PLA containing functional monomer. The complex viscosity and log G'vs. log G" plot among dynamic rheological properties were chosen for comparison. The complex viscosity of irradiated pure and chemically modified PLA decreased significantly due to de-gradation of PLA molecules with increasing the E-beam dosages. Complex viscosity of irradiated PLA with functional monomer showed maximum value at moderate dosage, while at high dosage the complex viscosity was decreased by a prolonged irradiation.