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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal Basic Information
Journal DOI :
The Polymer Society of Korea
Editor in Chief :
Volume & Issues
Volume 24, Issue 6 - Nov 2000
Volume 24, Issue 5 - Sep 2000
Volume 24, Issue 4 - Jul 2000
Volume 24, Issue 3 - May 2000
Volume 24, Issue 2 - Mar 2000
Volume 24, Issue 1 - Jan 2000
Selecting the target year
The Synthesis and Properties of Nonlinear Optical Polyquinonediimine Containing Mono-Azobenzene Group in the Side Chain
Polymer Korea, volume 24, issue 6, 2000, Pages 737~743
Polyquinonediimines (PQDI) which have stable structure on heat and contains mono-azobenzene in the side chain were synthesized by means of condensation polymerization under TiCl
. The synthesized monomers and polymers were identified by FT-IR,
H-NMR, and elementary analysis. Especially, PQDI was comfirmed by the double-bonding peak of >C=N appeared near 1625
/ by means of FT-IR spectrum. PQDI containing mono-azobenzene group in both side chains wat not soluble in non-polar solvents at all but partially soluble in the polar solvents having small dielectric constant, and dissolved in the strong acid such as sulfuric acid and
H. Molecular weight distribution of PQDI measured by GPC showed 1.74. It was confirmed through X-ray diffraction analysis that the polymer was partially crystalline at the low angle region, but amorphous after heat treatment at 1
. The glass transition temperature (T
) of synthesized polymer was measured as 1
by differential scanning calorimetry. The SHG value for
after poling at 1
was 8.6 pm/V (λ=1.542
). The SHG value slowly decreased with time from the start but appeared temporal stability after 100 hours.
Synthesis and Characteristics of PU Oil-Gelling Agents According to the Soft Segment Content
Polymer Korea, volume 24, issue 6, 2000, Pages 744~750
Oil gelling agent was synthesized with PPG, PTMG and TDI at 7
for 4hours. PPGs and PTMGs having various average molecular weights (M
: 1000, 2000, 3000) were employed to investigate the ratio of oil gelation and water gelation. As M
of PPG, in result, was decreased from 3000 to 1000, the ratio of oil gelation was increased from 130% to 290% for PPG and from 250% to 310% for PTMG. Ratio of oil gelation was increased approximately two times when EG was added. As the amount of hydrophilic compound in the prepolymer was increased, ratio of oil gelation was increased from 290% to 1120% for PPG and increased from 310% to 1310% for PTMG, due to the increased dispersion of prepolymer in the water/oil mixture.ure.
Copolymerization of Ethylene and Cycloolefin with Metallocene Catalyst: II. Effect of Cycloolefin
Polymer Korea, volume 24, issue 6, 2000, Pages 751~756
The copolymerization of ethylene (E) and cycloolefin (CO) was carried out with rac-Et(Ind)
and MMAO cocatalyst system to examine the effect of CO structure on catalytic behaviors and properties of copolymer (COC). Various cycloolefins such as norbornene (N), 5-phenyl-2-norbornene (PN) and 5-vinyl-2-norbornene (VN) were used as comonomers. With increasing [CO]/[E] feed ratio, the catalytic activity decreased while the glass transition temperature of copolymer increased. With analysis of the structure of E/VN copolymer by FT-IR and
C-NMR, it was found that the cyclic C=C bond of VN comonomer is selectively polymerized and the vinyl C=C bond remains unreacted. The resulting vinyl C=C bond attached into copolymer provided the functionalization moiety using glycidyl methacrylate.e.
Synthesis and Properties of Photocrosslinkable Polymers Containing Rosin Moiety (2)
Polymer Korea, volume 24, issue 6, 2000, Pages 757~762
Vinylbenzyloxystyrylpyridine (VSP) as a photosensitive monomer was synthesized by the reaction of 4-hydroxystyrylpyrydine with 4-vinylbenzyl chloride. Photocrosslinkable polymers containing rosin moiety were then prepared by radically copolymerizing VSP with a methacrylic monomer having rosin moiety. In these copolymerizations, the VSP feed ratios of 5 to 20 mol% were used. The contents of VSP units in the copolymers were determined by UV spectroscopy to be 5.3 to 17.3 mol%. The numberaverage molecular weights of these polymers were in the range of 18000 to 28000 and the polydispersity indexes were about 1.8. The glass transition temperatures were about 15
and the initial decomposition temperatures were about 34
. The polymers were relatively fast photocrosslinked and the photocrosslinking reaction could be traced by the UV spectroscopy and the residual yield method.
Synthesis of Multifunctional Polypropylene-g-(acrylic acid/styrene) Fibrous Ion Exchanger by Electron Beam and Adsorption Properties of Lithum Ion
Polymer Korea, volume 24, issue 6, 2000, Pages 763~769
The multifunctional cation exchangers, sulfonated polypropylene-g-(acrylic acid/styrene) [PP-g-(AAc/Sty)] were synthesized by the irradiational grafting of AAc and Sty onto PP staple fabric with electron beam accelerator and its subsequent sulfonation. The highest degree of grafting obtained was 190% at a monomer mixture of 30 vol% AAc: 70 vol% Sty and a solvent mixture of 30 vol% water : 70 vol% methanol and the degree of grafting decreased with an increase of the AAc content in the monomer mixture at constant solvent content. Maximum ion exchange capacity of the copolymer was 4.6 meq/g. The Li
adsorption ability of the copolymer synthesized in the study was the best among PP-g- AAc, sulfonated PP-g-Sty, and sulfonated PP-g-(AAc/Sty).).
Mechanical Properties of Talc-Filled Polypropylene : Coupling Agent Effect
Polymer Korea, volume 24, issue 6, 2000, Pages 770~776
The effect of unreactive coupling agent on mechanical and thermal properties of talc-filled polypropylene (PP) composites was studied. Stearic and oleic acids were introduced as coupling agents, and tensile, flexural, and impact strength, thermal stability and melting transition temperature were measured and analyzed according to the types and concentration of coupling agents. Tensile and flexural strength were enhanced by introduction of coupling agent and the maximum effect was observed at the concentration of 3 wt% of coupling agent. Tensile and flexural strength of PP treated with oleic acid were higher than those of PP treated with stearic acid. but impact strength vice-versa. The reasons for these results were postulated by analyzing morphologies of talc-filled PP observed by SEM.
Fire Resistance and Thermal Stability Study of Fire-Retarded Polypropylene Systems by Using Cone Calorimeter and Thermogravimetry
Polymer Korea, volume 24, issue 6, 2000, Pages 777~786
Fire resistance and thermal stability of polypropylene composite systems were investigated by using several halogenated fire-retardants such as decabromodiphenyl oxide (DBDPO) and chlorinated paraffin wax (CPW). The fire resistance of composite systems was thoroughly examined by measuring limited oxygen index (LOI, ASTM D2863, ISO 4589) and characteristic properties of cone calorimetry(ASTM E1354, ISO 5660) heat release rates (HRR), time to ignition (TTI), total heat release (THR), effective heat of combustion (EHC), mass loss rates, etc. Comparing the cone calorimetry experimental results of the halogen flame retardants, DBDPO exhibited twice higher efficiency than CPW in polypropylene systems, and the LOI also showed similar trends to cone calorimetry. The thermo-oxidative stability of the composite systems was increased about 30-5
in thermogravimetry analysis.Collectively, the combustion, extinction and thermally-stable characteristics of flame retardants were identified in this study.
Gelation Behavior of Acrylonitrile Copolymer/Dimethylformamide Solution and Mechanical Properties of Films Obtained from It′s Solution
Polymer Korea, volume 24, issue 6, 2000, Pages 787~793
The acrylonitrile copolymer/dimethylformamide (DMF) solutions were prepared to investigate the gelation behavior and critical gel concentration (c＊). Gelation is rapidly progressed with the increase of molecular weight of copolymer, but significantly delayed with supercooling temperature and comonomer contents. The c＊ behavior showed contrary trend against gelation behavior. In dynamic viscoelastic test, two glass-transition region were observed in film obtained from gelled solution whereas one glass-transition in film obtained from true solution. This result supports the idea that an ordered junction zone is formed by the dipole-dipole interaction of intermolecularly neighboring stereo-regular parts of atactic acrylonitrile copolymer chains due to a nucleation process in the solution.
Effects of Organosilicate Structure on Melt Intercalation of Thermoplastic Polymers
Polymer Korea, volume 24, issue 6, 2000, Pages 794~801
The effect of chain length and packing density of intercalated surfactants, annealing temperature, and annealing time on static melt intercalation of thermoplastic polymers was examined using x-ray and FTIR spectroscopy. Although melt intercalation of polymers was not successful when alkyl chains in organosilicates form a lateral monolayer structure, the type and structure of surfactants could not much affect final interlayer distances of most polymer/silicate hybrids. As annealing time increases, interlayer distance in organosilicates increases while the dispersity of the spacing between silicate layers decreases. However, the dispersity of interlayer spacing as well as interlayer distance in organosilicates increase with annealing temperature.
Counterion Specific Conformational Transition and ion Selective Transport of a Poly(L-glutamic acid)/PVA Blend Membrane
Polymer Korea, volume 24, issue 6, 2000, Pages 802~809
Counterion-specific helix formation and ion-selective transport of alkali metal chlorides (LiCl, NaCl, KCl, CsCl) were investigated for a poly(L-glutamic acid)(PLGA)/poly (vinyl alcohol)(PVA) blend membrane immersed in aqueous ethanol. The counterion specificity for helix formation of PLG alkali metal salts in the membrane was Li>Na>K>Cs. This specificity is ascribed to a contact ion-pair formation between the PLG carboxyl anion and the bound counterion, which depends on the energy balance between the electrostatic interaction and the desolvation. In aqueous ethanol, an appreciable ion-selectivity was observed for the permeability coefficient, i.e. Li
) formation between counterion and coion, and the latter to a specific interaction of diffusing counterions with polymer charges.
Determination of Tensile Modulus of PHB/PEN/PET Fiber Using Modified Halpin-Tsai Equation
Polymer Korea, volume 24, issue 6, 2000, Pages 810~819
Poly(p-hydroxybenzoate) (PHB)/poly(ethylene terephthalate) (PET) 8/2 thermotropic liquid crystalline copolyester, poly(ethylene 2,6-naphthalate) (PEN), and PET ternary blend was spun to fiber by melt spinninB process, and tensile properties of the fibers were measured. The matrix of the fibers, PET and PEN, were dissolved in ο-chlorophenol at 55
for 2 hours, and the liquid crystalline polymer fibrils were observed using a scanning electron microscope. Halpin-Tsai equation for modulus calculation of short fiber reinforced composite and the rule of mixture for continuous reinforcement composite were modified, and the tensile modulus were calculated and compared with experimental modulus. To minimize difference between the theoretical and the experimental moduli, dimensionless viscosity constant (K) was given and used to modify two equations. The theoretical tensile modulus using the newly modified equations presentel a similar to the experimental tensile modulus of composite, and the modified equations presented a unique way to determine the tensile modulus of the liquid crystalline polymer reinforced thermoplastic composites.
Barrier Property and Morphology of Biaxially Oriented PP/EVOH Blend Film
Polymer Korea, volume 24, issue 6, 2000, Pages 820~828
In this study, biaxially oriented film process was used to improve barrier property of polypropylene (PP)/ethylene-vinyl alcohol copolymer (EVOH) blends by inducing a laminar morphology of the dispersed phase in the matrix phase. In order to examine the extent of deformation during melt extrusion process, the rheological properties of the resins were measured and the viscosity ratio of the dispersed phase to the continuous phase was determined. The effects of compatibilizer content, draw ratio, and draw temperature on the oxygen permeability and morphology of biaxially drawn blend films were studied. The laminar morphology of the EVOH phase with a larger area of thinner layer induced by biaxial orientation was found to result in a significant increase in oxygen barrier property of PP/EVOH (85/15) blends by about 10 times relative to the pure PP When both PP-g-MAH and ionomer were used as the compatibilizers, there existed an optimum level of compatibilizer content for obtaining improved barrier properties with a well developed laminar structure. In addition, higher draw ratio and draw temperature were found to be more favorable processing conditions in obtaining higher barrier blends.
A Study on the Preparation ana Mechanical Properties of Composites Reinforced FRP Waste and Rock-Crush Sludge
Polymer Korea, volume 24, issue 6, 2000, Pages 829~836
In order to recyle the FRP waste from SMC bathtubs and rock-crush sludge obtained as a byproduct of stones, the composite consisting of the FRP and rock-crush sludge and the unsaturated polyester matrix resin were prepared. To enhance the interfacial bonding force between the reinforcements and the matrix resin, the rock-crush sludge was treated with silane coupling agent,
-MPS) and their mechanical properties and interface phenomena were examined. The flexural modulus of the composite containing 10 wt% rock-crush powder treated with 3 wt% silane coupling agent showed the maximum value. And also the initial thermal degradation temperature of composites were in the range of 352~359
. From these results, we observed that the weight loss of composites was almost constant regardless of the concentration of silane coupling agent. It is confirmed that the interface of the composites containing filler treated with
-MPS was improved in that there were no pull-out phenomena between the reinforcement and matrix resin.
A Study on the Cure Behavior of Epoxy Molding Compound
Polymer Korea, volume 24, issue 6, 2000, Pages 837~844
The cure behavior of commercial epoxy molding compounds (EMC) commonly used for IC package was studied at constant cure temperatures as well as at constant heating rates using differential scanning calorimetry (DSC), rheometer, and dielectric analyzer (DEA). The cure kinetics were obtained using autocatalytic reaction model according to the Ryan Dutta method after assuming m+n equal to 2. The prediction of reaction rates by the model equation corresponded well to experimental data at all temperatures except for 10
. The phase transitions such as gelation and vitrification occurred during network formation. At each isothermal cure temperature,
was measured in accordance with cure time, and the vitrification point was attained when
was equal to
. The temperature dependence of gel points and vitrification points showed good agreement with Arrhenius relation. DEA using parallel plate electrode was effective for the monitoring of EMC cure. we knew that if the resin systems are materials of comparable quality,
is constant regardless of accelerator concentration in TTT (Time-Temperature-Transformation) diagram.
The Improvement of Interlaminar Shear Strength for Low Density 2-D Carbon/Carbon Composites by Additives
Polymer Korea, volume 24, issue 6, 2000, Pages 845~853
The optimum cure cycle and carbonization condition were selected by the DSC and TGA analysis and green bodies were prepared by the method of hot press molding and then carbonized up to 140
. Additives such as graphite powder, carbon black, milled carbon fiber and carbon fiber mat, which were considered to be effective in improving the interlaminar shear strength, were also added to check their effects on the density and porosity of products. Then, their relations with mechanical properties such as ILSS and flexural strength were investigated. The composites added 9 vol% of graphite powder showed the greatest values of ILSS and flexural strength. Otherwise, in case of adding carbon black, the composites showed the slight improvement of ILSS at its contents of 3 vol% but the flexural strength was decreased. When milled carbon fiber and carbon fiber mat were added, the lack of resin and the heat shrinkage during the carbonization caused the delamination, resulting in decreasing the density, ILSS and flexural strength.
Synthesis of Block Copolymers Composed of Poly(N,N-dimethylamino ethyl methacrylate) and PEG and Formation of Nanoaggregation
Polymer Korea, volume 24, issue 6, 2000, Pages 854~859
The synthesis of poly(N,N-dimethylamino ethyl methacrylate (DMAEMA)-block-poly(ethylene glycol) (PEG)) copolymer has been carried out and the block copolymer was characterized by FT-IR, DSC, and
H-NMR. The formation of polymeric nanoaggregation was observed in the solution mixture of poly(DMAEMA) -block-PEG copolymer and poly (ethyl acrylamide) (EAAm) due to the intermolecular interaction via hydrogen bond between DMAEMA and poly(EAAm). The formation of polymeric nanoaggregation was observed above critical micelle concentration (CMC).
Electromagnetic Interference Shielding of Carbon Fibers-Reinforced Composites
Polymer Korea, volume 24, issue 6, 2000, Pages 860~868
In this work, the electro-magnetic interference (EMI) characteristics of PAN-based carbon fibers-reinforced composites are investigated with difference to manufactural parameters, i.e., fiber grade, fiber orientation angle, and laminating method. As a result, EMI shielding effectiveness (SE) of the composites greatly depends on a fiber orientation in composite angle. Especially, the fiber grade affects SE of composites in case of orientation angle of 0
. Then the SE become greater as the change of electric character according to the arrangement directions, i.e., electrical anisotropy in the same constituent materials. This is due to the skin effect which is represented in the surface of electro-magnetic wave in high-frequency range. In all cases according to lamination methods, the composites represents SE of 83~98% over. Whereas, in symmetric and unsymmetric laminate structures, the SE decreases slightly as the laminate angles of composites increases. On the contrary. the repeating laminates structure shows the opposite tendency. Especially, 90
repeating laminate structure shows the SE more than 90% over the measuring frequency.
Interaction of Fibroblast Cell onto Physicochemically Treated PLGA Surfaces
Polymer Korea, volume 24, issue 6, 2000, Pages 869~876
In order to improve the cell-compatability of poly(L-lactide-co-glycolide) (75 : 25 by mole ratio of lactide to glycolide, PLGA) surfaces, the physicochemical treatments have been demonstrated. Chemical treatments were 70% perchloric acid. 50% sulfuric acid and 0.5 N sodium hydroxide solution and physical methods were corona and plasma treatment. The water contact angle of surface treated PLGA decreased from 73
, i.e., increased hydrophilicity, due to the introduction of oxygen-containing functional group onto PLGA backbone by the measurement of an electron spectroscopy for chemical analysis. It could be observed that the adhesion and growth of fibroblast cell on physicochemically treated PLGA surfaces, especially perchloric acid treated PLGA surface, were more active than on the controt. In conclusion, it seems that surface wettability as hydrophilicity of PLGA plays an important role in cell adhesion, spreading and growth.
Interaction of Fibroblast Cells onto Chloric Acid-treated Poly(
-hydroxy acid) Polymer Surfaces
Polymer Korea, volume 24, issue 6, 2000, Pages 877~885
PLA, PGA and PLGA films were treated with chloric acid mixture solution [70% perchloric acid (HClO
)/potassium chlorate (KClO
) aq. saturated solution, 3 : 2] to increase surface wettability and thus cell compatibility. The surface-treated PLA, PGA, and PLGA films were characterized by the measurement of water contact angle, electron spectroscopy for chemical analysis, and scanning electron microscopy. Surface wettability of chloric acid-treated PLA, PGA, and PLGA film surfaces was gradually increased with increase of treatment time. Unlike EtOH pre-treatment, chloric acid-treated polymer films maintain hydrophilic surface after drying. In cell adhesion test, fibroblasts were cultured on the chloric acid-treated film surfaces for 1 and 2 days. As the surface wettability increased, the cell adhesion on the surface were increased. In conclusion, this study demonstrated that the surface wettability of polymer plays an important role for cell adhesion and proliferation behavior.
Characteristics of Poly(vinyl phenol) Ionomers Neutralized by LiOH and Their Miscibility with Poly(methyl methacrylate)
Polymer Korea, volume 24, issue 6, 2000, Pages 886~892
Poly(4-vinyl phenol) (PVPh) was neutralized by LiOH and PVPh ionomers (PVPh-Li) with different Li neutralization extents were synthesized. The variation in
with Li neutralization was determined by DSC and the results show that the
increases by 3.
per Li mol%. When comparing this result with the 3.
per Na mol% reported for poly (styrene-co-hydroxy styrene), the greater value for PVPh-Li may be due to a strong interaction between unneutralized free -OH and -OLi produced. No distinct small angle X-ray scattering (SAXS) peak was observed for these PVPh ionomers in bulk. In the 50/50 blend of PVPh-Li with PVPh, the miscibile blend was obtained when the Li neutralization in PVPh-Li was 10 mol%. On the contrary, the 50/50 PVPh-Li/PMMA was immiscible when the Li neutralization was 5 mol%. It can be concluded that, even if the starting blend is miscible owing to hydrogen bonding, the miscibility of blend becomes diminished by introducing small amount of ion groups into one of the constituent polymers and the blend can be immiscible as long as any new strong intermolecular ion-dipole interaction is not generated.