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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 25, Issue 6 - Nov 2001
Volume 25, Issue 5 - Sep 2001
Volume 25, Issue 4 - Jul 2001
Volume 25, Issue 3 - May 2001
Volume 25, Issue 2 - Mar 2001
Volume 25, Issue 1 - Jan 2001
Selecting the target year
Effect of the Amount of Catalyst and Chain-Initiator on the Anionic Polymerization of
Chung, Dae-Won ; Oh, Young-Taek ; Park, Young-Tae ;
Polymer Korea, volume 25, issue 1, 2001, Pages 1~5
Monomer casting nylons were synthesized by casting anionic polymerization of
-caprolactam. Polymerization rates, molecular weights of the products and the conversions were determined while varying the content of catalysts in the range of 0.2~0.6 mol% and 0.1~1.0 mol% for initiator. The polymerization rates were enhanced as the ratio of catalysts to initiator increased. The maximum molecular weight was observed when the ratio of catalysts to initiator was 0.8, and as the ratio increased the molecular weight decreased. On the other hand, when the ratio of catalysts to initiator was below 0.8, the conversions and the molecular weights were abruptly diminished due to the termination of growing chains.
Electrochemistry for Redox Polymer Film of N,N'-bis(3-pyrrol-1-yl-propyl)-4,4'-bipyridinium Ion
Cha, Seong-Keuck ;
Polymer Korea, volume 25, issue 1, 2001, Pages 6~14
The monomer N,N'-bis(3-pyrrol-1-yl-propyl)-4,4'-bipyridinium
was electrochemically polymerized on glassy carbon electrode surface. This polymer film electrode has electroactive sites on its bipyridinium ions distributed at the polymer strands. The formal potentials of the electrodes were -0.41V and -0.81V(vs. SSCE) for each step at phosphate buffer(pH=5.70). The diffusion coefficients of the dopants ions into the polymer matrix were
for first and second redox couple, respectively. The rate constants of electron transfer at
of the first step was a
, which was 22 times higher than
in the solution. The charge transfer resistance of the polymer film was influenced by the dopant ion of the electrolyte. Thus the resistances were 22.63, 16.81, 12.44 and
, and phosphate buffer, respectively. The reaction order of the electropolymerization was first order and the rate constant of the polymerization was
as determined by EQCM method. The G.C./p-BPB type electrode doped with phosphate ions showed a stability and reproducibility in CV procedure over 20 cycles.
Curing Behaviors and Viscoelastic of UPE Resins with Different Glycol Molar Ratios
Lee, Sang-Hyo ; Park, Yung-Hoon ; An, Seung-Kook ; Lee, Jang-Oo ;
Polymer Korea, volume 25, issue 1, 2001, Pages 15~24
In this study, the effects of different glycol molar ratios of unsaturated polyester(UPE) resins on the curing behaviors were investigated. The cross linking process was checked or monitored by differential scanning calorimetry(DSC) and by viscoelastic properties of rigid-body pendulum model. The knife-edge from which the pendulum is suspended, is immersed in a reaction mixture, and the change of the viscoelastic behavior brings on those of the period(T) and logarithmic decrement(
) of the damped free oscillations of the pendulum. The values of T and
obtained are related to the dynamic modulus(E') and modulus loss(E'). The information on the viscoelastic behavior of unsaturated polyester(UPE) resins during the curing process are shown to illustrate the usefulness of the techniques. As the content of NPG in a propylene glycol(PG)/NPG glycol mixture increased, both the cycle time during cure and the change of damping during cure of UPE resin decreased.
A Study on the Ester Interchange Reaction of Dimethyl Naphthalate with Ethylene Glycol
Sho, Soon-Yong ; Cheong, Seong-Ihl ;
Polymer Korea, volume 25, issue 1, 2001, Pages 25~32
The kinetics of ester interchange reaction of dimethyl naphthalate(DMN) with ethylene glycol(EG) has been studied in the range of 180-200
using zinc and manganese catalysts. The reaction was performed in a semibatch reactor under nonisothermal condition and the degree of reaction was calculated from experimental data of methanol removal rate and reaction temperature. As a reaction model, both the functional group model and the molecular species model were applied and analysed. In case of zinc catalyst, the ratio of reaction rate of methyl hydroxyethyl naphthalate(MHEN) with EG on that of DMN with EG is about 1.4, whereas in case of manganese catalyst the ratio is about 4.3, which implies that the reaction rate is quite dependent on the type of catalyst. In case of zinc catalyst, the reaction order of catalyst concentration on either DMN or MHEN and EG is less than 1, whereas in case of manganese catalyst, the reaction order is larger than 1. The activation energy for zinc and manganese catalyst, irrespective of the type of molecular species, e.g., DMN and MHEN, were found to be 25000 and 28750 cal/mol, respectively. As a result of comparing two reaction model, the molecular species model fits well for the experimental data.
Synthesis and Surface Properties of Fluorinated Polyurethanes
Kim, Hyung-Joong ;
Polymer Korea, volume 25, issue 1, 2001, Pages 33~40
Fluorinated polyurethane elastomers were synthesized by two step polyaddition of a perfluorinated polyether diol(trade name of Fomblin
) and diisocyanates such as 4,4'-diphenyl methane diisocyanate(MDI) and toluene 2,4-diisocyanate(TDI). In order to control the Fomblin moiety of the soft segment in the synthesized elastomers to 10~50%, polyether type polyols such as polypropylene glycol(PPG) and polytetramethylene glycol(PTMG) were mixed during the polymerization reaction. Ethylene diamine or 1,4-butane diol was used as chain extenders. The structure and average molecular weight of the produced polyurethanes were confirmed by using FT-IR,
, DSC, and GPC. The surface properties were analyzed by using X-ray photoelectron spectroscopy(XPS) and contact angle meter. From the results of the surface analysis it was concluded that the fluorine groups were localized on the surface rather than the inside of the polyurethane films.
Preparation and Physical Properties of the Polyurethane Microgels Based on Poly(caprolactone) diol/Poly(ethylene glycol)
Lim, Jeong-Soo ; Kim, Kong-Soo ; Lee, Moo-Jae ; Lee, Young-Geun ;
Polymer Korea, volume 25, issue 1, 2001, Pages 41~48
Polyurethane(PU) microgels were synthesized from poly(caprolactone) diol(PCD) and/or poly(ethylene glycol)(PEG), diisocyanate and 1,2,6-hexane triol by solution polymerization method. A critical gelation concentration of the PU microgels with, mole ratios of PCD/PEG were the important factors influencing the formation and property microgel or macrogels. The physical and thermal properties of the PU microgels prepared with depending upon the structure of diisocyanate, mole ratio of PCD/PEG, and molecular weight of PEG were investigated. It was found that PU microgels were distributed by polydisperse, spherical small particles below 300nm and showed the properties of low viscosity.
Synthesis of SAPP-g-(AN/St) Fibrous Ion-Exchanger by E-beam Pre-irradiation and Their Adsorption Properties for Uranium Ion
Hwang, Taek-Sung ; Park, Jin-Won ; Kim, Kwang-Young ;
Polymer Korea, volume 25, issue 1, 2001, Pages 49~55
The bi-functional ion exchangers, SAPP-g-(AN/St) were synthesized with mixed vinyl monomers(acrylonitrile and styrene) onto PP fabric by the pre-irradiation grafting with E-beam and its subsequent amidoximination and sulfonation. The degree of grafting of PP-g-(AN/St) was increased with decreasing acrylonitrile composition in the mixed monomers. The water uptake of copolymers increased with decreasing in the amidoxime ratio in the copolymers and increased by sulfonation, but decreased by amidoximation. The
adsorption capacity of SPP-g-St, APP-g-AN, and SAPP-g-(AN/St) were 12.4, 34.0, and 38.0 mg/g, respectively and the optimum adsorption time is about 50 hrs. As a result of uranium adsorption, the synthesized ion exchanger, which we obtained have also good affinity toward the adsorption or chelating with
Annealing Effect in the Cold-Plastic Deformation of Amorphous PET Material
Lee, Jong-Young ; Park, Seong-Soo ;
Polymer Korea, volume 25, issue 1, 2001, Pages 56~62
When polyethylene terephthalate(PET) film specimen were stepwise elongated under tension with various speeds of about 0.5~500 mm/min, the necking area, consisted of transparent and opaque bands, was formed during plastic deformation. Stress oscillation was apparently obtained in the stress-strain curve of above specimen. However, stress oscillation was not obtained in the stress-strain curve of annealing specimen. Microstructure was examined dynamically using an optical microscopy and thermal analysis was carried out in a differential scanning calorimeter at a heating rate of 10
/min. Also, orientation and crystallization were examined using monochromatic-pinhole technique and elastic modulus was measured by a dynamic mechanical analyzer in the temperature range of -150~70
with the frequency of 1 Hz. Transparent PET products were fabricated by use of the PET pellets annealed at 83
for 30 min in an electric furnace.
Effect of Various Cross-linking Types on the Physical Properties in Carbon Black-Filled Natural Rubber Compound
Park, Byung-Ho ; Jung, Il-Gouen ; Park, Sung-Soo ;
Polymer Korea, volume 25, issue 1, 2001, Pages 63~70
The objective of this study was to investigate the effect of cure type on the processing and physical properties under conditions of similar stress-strain properties. On the carbon black filled natural rubber(NR) based compound, the induction time decreased, but the cure rate became fast with increasing loading of sulfur donor agent. Tensile strength was little affected on the curing type. However, elongation generally decreased with increasing accelerator. Effect of cure type on the blow-out properties was followings: CV
Toughness of Polyurethane-Modified Unsaturated Polyester Resin
Hwang, Yeong-Geun ; Min, Kyung-Eun ; Choi, Gwan-Young ; Kim, Woo-Sik ; Lee, Dong-Ho ; Park, Lee-Soon ; Seo, Kwan-Ho ; Kang, Inn-Kyu ; Jun, Il-Ryun ;
Polymer Korea, volume 25, issue 1, 2001, Pages 71~77
Unsaturated polyester(UP) resin is one of the major thermosetting resins. It is very useful as the matrix resin of the composite material because of its low viscosity. The polymer resin, however, has several drawbacks; The volume shrinkage occurs during the crosslinking reaction of the UP resin with styrene monomer and the resulting polymer is weak to the alkali and also brittle. The mechanical properties of UP resin can be improved by blending various materials. In this study, polyurethane(PU) was used as a modifier in order to enhance the toughness of the UP resin. The goal of the research is to study the effect of the polyol molecular weight as a PU soft segment and the PU contents on the toughness of PU-modified UP resins. UP/PU polymer network may occur through the reaction between isocyanate group in the methyldiisocyanate(MDI) and hydroxyl group in the UP molecules. The maximum toughness value was shown at 2 wt% of the PU content. This effect results from the incorporation of the PU segment into the UP resin.
The Study on Phase Separation Development by Curing Reaction Rate for Unsaturated Polyester/Polyvinylacetate Semi-IPN
Chang, Won-Young ; Kim, Moo-Sool ; Kim, Jin-Hwan ; Nam, Jae-Do ;
Polymer Korea, volume 25, issue 1, 2001, Pages 78~89
Morphological changes of unsaturated polyester/polyvinylacetate semi-IPN were studied while the phase separation and the cure reaction occurred in a competing fashion. The light scattering and thermal analysis techniques were used to investigate the phase separation rates and mechanical properties resultantly induced by molecular diffusion of thermoplastic polymer during the curing process of thermosetting polymer. The reaction activation energy was calculated by using Flynn-Wall method and the semi-IPN structure exhibited various phase-separation morphological characteristics. When PVAc composition was 10 wt%, the phase separation was not observed during the curing reaction, but the phase separation occurred in a similar fashion to nucleation and growth(NG) mechanism at room temperature. On the other hand, when PVAc composition was over 11.65 wt%, the phase separation was generated in the middle of the curing process. Consequently, the phase separation seemed to influence the curing reaction rate, which was also supported by the changing activation energy with conversion and PVAc composition. Finally, the total scattered intensity was measured at various temperature, and subsequently the diffusion rates of phase separation R(
) were evaluated.
Urea Diffusional Characteristics of Film from Dispersion Based on Poly(ethylene-co-acrylic acid)
Yu, Dong-Guk ; An, Jeong-Ho ;
Polymer Korea, volume 25, issue 1, 2001, Pages 90~97
Dispersions are prepared from poly(ethylene-co-acrylic acid) (PEAA) ionomer with two different counter-ions, ammonium and sodium. The diffusional characteristic of urea aqueous solution are measured for the films prepared from the above mentioned dispersions. It is attempted to find the relationship between diffusional behavior and various chemical and physical characteristics of films. DSC is employed to characterize glass transition temperature and degree of crystallinity and the structural features of crystal phase and ionic clusters are examined by WAXD and FTIR. The diffusional characteristics of ionomer is found to be dependent on various parameters such as the size of initial dispersion as well as the kind of counter ion and the degree of neutralization.
A Study on the Dielectric Properties of SBS/Conductive Filler/Dielectrics Composites for Phantom Model
Kim, Yoon-Jin ; Choi, Hyung-Do ; Cho, Kwang-Yun ; Yoo, Don-Sik ; Yoon, Ho-Gyu ; Suh, Kwang-Seok ;
Polymer Korea, volume 25, issue 1, 2001, Pages 98~107
Dielectric properties and shape memory characteristics of SBS composites filled with carbon black as conductive filler and (Ba,Ca)
as dielectrics were investigated for the development of phantom model. SBS/carbon black composite showed an increment of complex dielectric constant with increasing the content of carbon black and the frequency dependence that the dielectric constant decreases with the frequency. The complex dielectric constant and the conductivity of SBS/carbon black/dielectrics composites increased with the increase of dielectrics and the characteristics of the frequency dependence also occurred by the effect of carbon black. Phantom materials with the dielectric properties and the conductivity corresponding to human tissues for the measurement of specific absorption rate(SAR) within the frequency range of current mobile phones(775MHz~2GHz) could be developed by adjusting the composition ratios of carbon black, dielectrics and SBS and by controlling the characteristic of frequency dependence of composite. From thermomechanical cycling test good shape recoverability could be obtained in SBS composite even though the residual strain was increased by the effect of filler.
Molecular Design and Characterization of Biodegradable Crosslinked Copolyesters
Sung, Yong-Kiel ; Han, Seung-Jun ;
Polymer Korea, volume 25, issue 1, 2001, Pages 108~114
Crosslinked poly(glycerol-co-malate)s were synthesized from L-malic acid in Krebs cycle and glycerol. The synthesized polymer was identified by FT-IR spectroscopy. Swelling degrees of the copolymer hydrogels were increased with an increase in pH of the aqueous solution. Hydrolytic behaviors of the crosslinked copolymers were investigated in various pH buffer solutions at 37
. The Hydrolysis of the copolymers proceeded faster with increasing pH of the aqueous solution. Releasing behaviors of the model drug such as diclofenac monosodium salt were also measured in various pH aqueous solutions at 37
. The release concentration of diclofenac monosodium salt from the hydrogel systems was increased with increasing pH. These facts indicate that the unreacted carboxyl and hydroxyl groups in the copolymers are greatly affected by pH in the conditions.
Studies on the Syndiotactic Poly(vinyl alcohol) Polarizing Film -Iodine Desorption Behavior of High Molecular Weight Syndiotactic Poly(vinyl alcohol)/Iodine Complex Film-
Lyoo, Won-Seok ; Yeum, Jeong-Hyun ; Choi, Jin-Hyun ; Ji, Byung-Chul ; Yoon, Won-Sik ; Noh, Tae-Hwan ; Ghim, Han-Do ; Kim, Jae-Pil ;
Polymer Korea, volume 25, issue 1, 2001, Pages 115~121
High molecular weight syndiotactic poly(vinyl alcohol)(HMW s-PVA) with number-average degree of polymerization of 10000 and syndiotactic diad content of 61.5%/iodine complex film was prepared. Its adsorption and desorption behaviors of iodine in hot water were investigated. In comparison with atactic PVA film or low molecular weight s-PVA film, the degree of solubility of s-PVA film and the iodine desorption of HMW s-PVA/iodine film in hot water were limited to an extremely lower level. As the soaking time increased, the iodine desorption in hot water was increased. This reason might be explained by the fact that as the soaking time increased, so the iodine adsorption increased not by the stable molecular complex between PVA and iodine but by the simple physical adsorption of iodine.
Thermoplastic Film Infusion Process for Long Fiber Reinforced Composites Using Rubber Expandable Tools
Kim, Dong-Wook ; An, Young-Sun ; Lee, Young-Kwan ; Kim, Seong-Woo ; Nam, Jae-Do ;
Polymer Korea, volume 25, issue 1, 2001, Pages 122~132
Thermoplastic film infusion process was investigated by using a rubber tool, which intrinsically contains a thermally-expandable characteristic and effectively compensates for the pressure loss caused by thermoplastic polymer infusion. Increasing temperature up to the melting temperature of matrix, the polymer melt subsequently infused into the dry fabric, but the pressure was successfully sustained by the rubber tool. Even with the decreased resin volume, the rubber tool produced sufficiently high elastic force for continuous resin infusion. Combining D'Arcy's law with the compressibility of rubber tool and elastic fiber bed, a film infusion model was developed to predict the resin infusion rate and pressure change as a function of time. In addition, the film infusion process without the rubber tool was viewed and analyzed by a compression process of the elastic fiber bed and viscous resin melt. The compressibility of fiber bed was experimentally measured and the multiple-step resin infusion was well described by the developed model equations.
Influence of Oxidation Inhibitor on Carbon-Carbon Composites: 6. Studies on Friction and Wear Properties of Carbon-Carbon Composites
Park, Soo-Jin ; Seo, Min-Kang ; Lee, Jae-Rock ;
Polymer Korea, volume 25, issue 1, 2001, Pages 133~141
The friction and wear properties of carbon-carbon composites made with different weight percent of
as an oxidation inhibitor were investigated using a constant speed wear test apparatus in an oxidation environment. The results indicated the carbon-carbon composites undergoing an abrupt transition of friction coefficient, from low-friction behavior(
=0.15~0.2) during normal wear regime to the high-friction behavior(
=0.5~0.6) during dusting wear regime at the frictional temperature range of 150~180
. The existence of temperature-dependent friction and wear regimes implied that the performance of specimen made with carbon-carbon composites was markedly affected by the thermal properties of the composites. The carbon-carbon composites filled with MoSi2 exhibited two times lower coefficient of friction and wear rate in comparison with the composites without
. Especially, the composites containing 4wt%
filler showed a significantly improved activation energy for wear due to the reduction of both the porosity and powdery debris film formation on sliding surface when compared to those without
Development of Environmental Rubber Interphase Adhesive by use of Oligomer of Hydrocarbon
Jang, Byung-Man ; Jang, Jeong-Seog ; Park, Sung-Soo ; Choi, Dug-Jai ; Kim, Su-Kyung ;
Polymer Korea, volume 25, issue 1, 2001, Pages 142~150
Until now rubber industry field has used organic solvent base adhesive, there was always existed a fire risk, variety of quality and harmfulness of human body. To solve this problem we were developed a new adhesive that was maked by raw materials of hydrocarbon series which has the properties of nonvolatile and high flash point. Because of this new adhesive has the properties of nonvolatile and non-harmfulness to the human body, we expected to solve the problems of a fire hazard and the pollution of the environmental. Instead of the rubber binder that is used to a present adhesive, the new idea is adopted in a new type of adhesive. Nonvolatile solvent penetrated to the rubber surface and caused the swelling in rubber surface and as a result of this action, it has the self-adhesive power. In comparision with the present adhesive a new type of adhesive remarkably improved the maintenance time of adhesion and the durability of this adhesive showed similar aspect. Because it did not exhibit a drop of physical properties of rubber which was caused by swelling effect, we estimate that new type adhesive are very stable and not reacted to several rubber additives. While present adhesive appear the crack at cutting surface of curing rubber that caused by gas, new type adhesive not exist these crack.