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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 30, Issue 6 - Nov 2006
Volume 30, Issue 5 - Sep 2006
Volume 30, Issue 4 - Jul 2006
Volume 30, Issue 3 - May 2006
Volume 30, Issue 2 - Mar 2006
Volume 30, Issue 1 - Jan 2006
Selecting the target year
Functional Polymeric Materials for Biomedical Application
Sung, Yong-Kiel ; Song, Dae-Kyung ; Sung, Jung-Suk ;
Polymer Korea, volume 30, issue 1, 2006, Pages 1~9
The development of functional polymeric materials for biomedical application has progressed on the basis of functionality, biocompatibility and biodegradability. In this paper we review the functional polymeric biomaterialsbased systems and propose a range of biomedical applications in the near future. These systems include the functional biodegradable polymers synthesized in our research laboratory, biodegradable polymeric materials, thermosensitive polymeric materials, cationic polymeric materials, non-condensing polymeric biomaterials, bio-polymeric DNA matrix for tissue engineering, and polymeric biomaterials for RNA interference (RNAi) technology.
Effects of Antioxidant and Thermal Treatment on the Radiation Resistance of Polypropylene
Park Sung Hyun ; Kim Hyung-Il ; Kang Phil Hyun ; Nho Young Chang ;
Polymer Korea, volume 30, issue 1, 2006, Pages 10~13
The effects of antioxidants and thermal treatment on the radiation resistance of the gamma-ray irradiated polypropylene (PP) were studied. The PP was blended with various antioxidants and was fabricated into a sheet. The PP sheet was irradiated with gamma-ray to a dosage of 25kGy in the nitrogen atmosphere. The differences in both color and mechanical strength were investigated for the gamma-ray irradiated PP depending on the kind and the content of antioxidant. The residual amount of free radical and the variation of oxidation index were investigated for the gramma-ray irradiated PP with thermal treatment after irradiation. The PP having phosphite antioxidant showed little difference in color after gamma-ray irradiation compared with the PP having phenolic or mine antioxidant. Sufficient amount of free radical could be removed from the gamma-ray irradiated PP by the thermal treatment at
for 30 min. Thermally treated PP showed lower oxidation index than the PP without thermal treatment.
Effects of SIS/PLGA Porous Scaffolds and Muscle-Derived Stem Cell on the Formation of Tissue Engineered Bone
Kim Soon Hee ; Yun Sun Jung ; Jang Ji Wook ; Kim Moon Suk ; Khang Gilson ; Lee Hai Bang ;
Polymer Korea, volume 30, issue 1, 2006, Pages 14~21
Tissue engineering techniques require the use of a porous biodegradable/bioresorbable scaffold, which server as a three-dimensional template for initial cell attachment and subsequent tissue formation in both in vitro and in vivo. Small intestinal submucosa (SIS) has been investigated as a source of collagenous tissue with the potential to be used as biomaterials because of its inherent strength and biocompatibility. SIS-loaded poly(L-lactide-co-glicolide)(PLGA) scaffolds were prepared by solvent casting/particle leaching. Characterizations of SIS/PLGA scaffold were carried out by SEM, mercury porosimeter, and so on. Muscle-derived stem cells can be differentiated in culture into osteoblasts, chondrocytes, and even myoblasts by the controlling the culture environment. Cellular viability and proliferation were assayed by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide(MTT) test. Osteogenic differential cells were analyzed by alkaline phosphatase(ALP) activity. SIS/PLGA scaffolds were implanted into the back of athymic nude mouse to observe the effect of SIS on the osteoinduction compared with controlled PLGA scaffolds. Thin sections were cut from paraffin embedded tissues and histological sections were conducted hematoxylin and eosin (H&E), Trichrome, and von Kossa. We observed that bone formatioin of SIS/PLGA hybrid scaffold as natural/synthetic scaffold was better thean that of only PLGA scaffold. It canb be explained that SIS contains various kinds of bioactive molecules for osteoinduction.
The Characteristics of Poly(ethylene naphthalate)/Poly(butylene terephthalate) Blends
Kim Hyokap ; Kang Ho-Jong ;
Polymer Korea, volume 30, issue 1, 2006, Pages 22~27
The effect of transesterification on the rheological property of poly(ethylene naphthalate)/poly(butylene tore-phthalate) (PEN/PBT) blends has been investigated. The melt viscosity of PEN/PBT blends decreased with increasing PBT content due to the relatively low melt viscosity of PBT as well as introducing ransesterification between PEN and PBT Further melt viscosity decrease was achieved by the thermal annealing which caused both the chain scission and the acceleration of transesterfication. Calcium stearate (CaST) was applied as a lubricant in order to lower the melt viscosity of PEN and it was found that CaST was acting as the catalyst of transesterification as well. In general, reactive melt blending of PEN and PBT by transesterification resulted in the decrease of molecular weight of PEN and PBT, as a result, the loss of mechanical properties in PEN/PET blend was inevitable.
Synthesis and Characterization of Biodegradable MethoxyPoly(ethylene glycol)-Poly
Hyun Hoon ; Cho Young Ho ; Jeong Sung Chan ; Lee Bong ; Kim Moon Suk ; Khang Gilson ; Lee Hai Bang ;
Polymer Korea, volume 30, issue 1, 2006, Pages 28~34
A series of methoxypoly(ethylene glycol)
(PCLA) diblock copolymers were synthesized by ring-opening polymerization of a mixture of
and L-lactide with different ratios in the presence of
. The characterization of MPEG-PCLA diblock copolymers were examined by
, GPC, DSC, and XRD. Kinetic study on ring-opening polymerization of monomer mixtures was carried out in various conditions such as a variation with polymerization time, amount of catalyst, and temperature. The highest conversion obtained in 1.2 ratic of initiator venn catalyst at
. The biodegradable characterization of MPEG-PCLA diblock copolymers in aqueous solution was carried out by using GPC for
weeks. The biodegradability of MPEG-PCLA diblock copolymers increased as the L-lactide content of diblock copolymers increased. In conclusion, we confirmed the dependence of polymerization rate according to various conditions. In addition, we can control the biodegradability of MPEC-PCLA diblock copolymers by changing the ratio of PCL and PLA block segment.
Thermotropic Liquid Crystalline Behavior of Poly(1-cholesteryloxycarbonyloxy]ethylene] and Poly[1-(cholesteryloxycarbonylheptanoyloxy)ethylene]
Jeong, Seung-Yong ; Ma, Yung-Dae ;
Polymer Korea, volume 30, issue 1, 2006, Pages 35~44
Poly[1-(cholesteryloxycarbonyloxy)ethylene](PCOE) and poly[1-(cholesteryloxycarbonylheptanoyloxy)ethylene] (PCOSE) were prepared by reacting poly(vinyl alcohol) with cholesteryl chloroformate or 8-cholesteryloxycarbonylheptanoly] chloride (CH8C), and their thermal and optical properties were investigated. CH8C formed a monotropic cholesteric phase whereas PCOE and PCOSE exihibited enantiotropic cholesteric phases. Like in the case of CH8C, the optical pitch
of PCOSE decreased with increasing temperature. PCOE, contrast with PCOSE, did not display reflection colors, suggesting that the helical twisting power or the cholesteryl group highly depends on the length or the spacer joining the cholesteryl group to the main chain. The mesophase properties of PCOE and PCOSE were entirely different from those of poly
. The results indicate that the mode of chemical linkage of the side chain group with the main chain plays an important role in the formation, stabilization, and temperature dependence of
of the cholesteric mesophase.
Separation Reaction Characteristics of Boron Ion by Ion Exchange Method
Jung Boo-Young ; Kang Suk-Hwan ; Lee Jae-Chun ; Hwang Taek-Sung ;
Polymer Korea, volume 30, issue 1, 2006, Pages 45~49
In this study, it was investigated on the boron separation ken synthetically prepared seawater. ion exchange resin used in the experiments was Amberlite IRA 743, containing glucamine functional group. The experiments were carried out as a function of the conditions of the pH, boron initial concentration and temperature of seawater in a batch reactor. As a result, optimum conditions for boron adsorption were at pH 8.5 and 313 K, respectively. The adsorption rate was increased very fast with increasing the temperature, but decreased with increasing the initial concentration of boron. Also, the kinetics for boron adsorption applied the pseudo-second order model, as follows:
Surface Morphology Control of Monodisperse Crosslinked-Polymer Particle
Kim, Dong-Ok ; Jin, Jeong-Hee ; Oh, Seok-Heon ;
Polymer Korea, volume 30, issue 1, 2006, Pages 50~55
When the monodisperse polystyrene(PS)/HDDA polymer particles were synthesized via one-step polymerization using polystyrene seed particles by dispersion polymerization, the effects of 1) the molecular weight of seed polymer particles, 2) the ratio of the absorbed HDDA to the seed polymer particles (swelling ratio) and 3) seeded polymerization rate on the surface morphology of PS/HDDA polymer particles were investigated. It was observed that the creation of the crater shaped defect on the surface of PS/HDDA polymer particles was irrespective of the molecular weight of seed polymer ant swelling ratio. But its surface morphology could be controlled by the change of the seeded polymerization rate.
Synthesis of Polyimides with Layered Structure from Diamines Containing Flexible Side Chains
Han Seung San ; Yi Mi Hye ; Choi Kil-Yeong ; Im Seung Soon ; Kim Yong Seok ;
Polymer Korea, volume 30, issue 1, 2006, Pages 56~63
We have synthesized two types of diamine monomers containing various chain length to prepare polyimides with layered structure. By using these diamines, homo-polyimides and co-polyimides having hydrophobic and hydrophilic segment of flexible side chain were synthesized. The segregated layered structures were formed by repulsive force with main chain as the side chains reach a critical length because the rigid main chains are packed into layered structure with the flexible side chains occupying the space between layers. As a result, the gallery space of each homo-polyimide was increased at spacing of
as the increased hydrophobic or hydrophilic side chain length through X-ray diffraction. The gallery space of co-polyimides was also showed similar phenomenon by repulsive force of side chains with different properties. We have also confirmed that gallery space and molar volume were significantly depended on length of flexible side chain via molecular modeling.
Syndiotactic Polymerization of Styrene Catalyzed by Dinuclear (Cyclopentadienyl) (Aryloxy) Titanium(IV) Complexes with Polymethylene Bridge
Kum Don-Ho ; Jung Woosung ; Kim Kyungsik ; Noh Seok Kyun ; Lee Dong-Ho ; Lyoo Won Seok ;
Polymer Korea, volume 30, issue 1, 2006, Pages 64~69
A series of dinuclear half-sandwich titanium complexes with aryloxy substituent at titanium
(n=3, n=6, n=9) have been successfully synthesized and their styrene polymerization properties have been investigated. All complexes are characterized by
, elemental analysis, and mass spectrometry. In order to examine the catalytic properties of the dinuclear complexes styrene polymerization has beer conducted in the presence of MMAO. It was found that (i) all the prepared complexes were very effective catalyst for the production of SPS (syndiotactic polystyrene), (ii) the complex with the longest bridge between the two active sites exhibited greatest catalytic activity among the three catalysts, but produced SPS with the smallest molecular weight, (iii) the activities of dinuclear half-titanocens with aryloxy substitution at titanium metal were greater than those of the chloride substituted compounds. These results indicate that not only the nature of the bridge between the two active sites but also the property of substituents at the metal exert a significant influence on the polymerization behaviors of the dinuclear half-titanocene.
Preparation of Cellulose Diacetate/Ramie Fiber Biocomposites by Melt Processing
Lee Sang Hwan ; Lee Sang Yool ; Nam Jae Do ; Lee Youngkwan ;
Polymer Korea, volume 30, issue 1, 2006, Pages 70~74
Plasticized cellulose diacetate(CDA) was prepared by homogenizing cellulose diacetate(CDA), triacetin(TA) and epoxidized soybean oil (ESO) in a high-speed mixer, then the CDA mixture was mixed with ramie fiber to produce a green composite material. In DMA analysis, the glass transition temperature of plasticized CDA and the composite was observed at
, respectively. A composite reinforced with alkali treated ramie fiber exhibited significantly higher mechanical properties, such as
increase in tensile strength as well as
increase in Young's modulus when compared with commercial polypropylene. In the SEM image analysis, much enhanced adhesion between plasticized CDA and alkali treated ramie fiber (AIRa) was observed.
Synthesis of Silica Nanoparticles Having the Controlled Size and their Application for the Preparation of Polymeric Composites
Kim, Jong-Woung ; Kim, Chang-Keun ;
Polymer Korea, volume 30, issue 1, 2006, Pages 75~79
Silica nanoparticles for polymeric dental restorative composites were prepared by Stober method, and then the effects of surface treatment of silica particles with Lmethacrylofpropyltrimethofsilane
on the dispersity of the silica particles in the organic matrix was investigated. Particles having various average size were prepared by using controlled amounts of tetraethylorthosilicate(TEOS), water, and catalyst and by changing solvent used for reaction. The site of particles prepared by using methanol as solvent was smaller than that prepared by using ethanol as solvent. In addition, the size of particles was increased by decreasing amounts of water and by increasing amounts of TEOS and catalyst. Hydrophobic silica nanoparticles was prepared by reacting hydrophilic nanoparticles with
to improve interfacial properties with organic matrix. Amounts of
per unit mass of the particles was increased by decreasing particle size. even though the amount of
per specific surface area were nearly the same regardless of the particle size. The dispersity of the silica particles in the organic matrix was improved when the surface treated silica particles were used for preparing the polymeric dental restorative composites.
Preparation of Poly(2-biphenylyl acrylate-co-methacrylic acid) and Release of 2-Phenylphenol
Hyun Seok-Hee ; Kim Min-Woo ; Jeon Il-Ryon ; Son Seog-Ho ; Baek Chang-Hoon ; Kim Woo-Sik ;
Polymer Korea, volume 30, issue 1, 2006, Pages 80~84
2-Biphenylyl acrylate(BPA) was synthesized by the reaction of acryloyl chloride with 2-phenylphenol (2PP). Hydrophilic copolymers with the moiety of the microbicide, 2PP, were prepared by the radical copolymerization of BPA and methacrylic acid (MA). From the compositions of the BPA unit and the MA unit in the copolymers, the monomer reactivity ratios were determined to be 0.86 for BPA and 1.21 for MA by means of Kelen-Tudos plot. This result indicates that the copolymers have a random structure. The amount of 2PP released through the hydrolysis of the copolymers was examined by UV spectrometry. The result showed that the release of 2PP increased with an increase in the hydrophilic MA content in the copolymers and with an increase in the pH of the release medium. Therefore, these results indicate that the hydrophilic polymers bearing 2-phenylphenol moiety can be controlled release microbicides.
Electrical and Rheological Behaviors of VGCF/Polyphenylene Sulfide Composites
Noh, Han-Na ; Yoon, Ho-Gyu ; Kim, Jun-Kyung ; Lee, Hyun-Jung ; Park, Min ;
Polymer Korea, volume 30, issue 1, 2006, Pages 85~89
The effect of vapor grown carbon fiber (VGCF) contents on electrical and rheological properties of VGCF filled polyphenylene sulfide (PPS) composites prepared through melt mixing using a twin screw exruder was studied. This method was proved to be quite effective to produce good dispersion of VGCF in the matrix even for highly filled PPS. From the dependence of the electrical conductivity on VGCF content, the percolation phenomena began to occur above
. While there is only a marginal increase of viscosity for 1 and
VGCF filled PPS, the composites containing
. While VGCF showed abrupt increase in viscosity as well as flattening of frequency vs modulus curve, indicating a transition from a liquid-like to a solid-like behavior due to the creation of VGCF network. This result agrees well to the fact that the network formation in the composite can be composite by rheological property dependence on filler content as well as by electrical conductivity measurement.
Characteristics of Electrospun Poly(methyl methacrylate) Nanofibers Embedding Multi-Walled Carbon Nanotubes(MWNTs)
Kim Dong Ouk ; Lee Dai-Hoi ; Yoon Seong-sik ; Lee Sun-Ae ; Nam Jae Do ;
Polymer Korea, volume 30, issue 1, 2006, Pages 90~94
An electrospinning process was used to fabricate poly(methyl methacrylate) (PMMA) nanofibers embedding multi-walled carbon nanotubes(MWNTs). SEM images showed that the nanofiber surface and structural morphology depended on solvent types (dimethyl formamide, chlor-form and toluene) and carbon nanotube contents (0.5 and
). Nano-fiber alignments could be controlled by adjusting the electrodes configuration at collector sites. Relationship between carbon nanotube and PMMA nanofiber was studied with radius of gyration of polymer chain and carbon nanotube sizes. As the carbon nanotube content ratio increased, the number of bead increased.