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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 39, Issue 3 - May 2015
Volume 39, Issue 2 - Mar 2015
Volume 39, Issue 1 - Jan 2015
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Optical and Mechanical Properties of Styrene/Butyl Acrylate/Methyl Methacrylate Terpolymers
Jang, Sang Jin ; Park, Hae Youn ; Seo, Kwan Ho ;
Polymer Korea, volume 39, issue 2, 2015, Pages 191~199
DOI : 10.7317/pk.2015.39.2.191
In order to improve the low impact resistance of polystyrene without harming its transparency the styrene monomer was copolymerized with transparent butyl acrylate (BA), and methylmethacrylate (MMA) to obtained a poly(styrene-co-butylacrylate) P(SM-co-BA) and a terpolymer copolymer P(SM-co-BA-co-MMA). The polymers were then cross-linked with the aid of a cross-linking agent dicumylperoxide (DCP), and their mechanical and optical properties were tested. It was found that the contents of monomers and DCP affect the mechanical, thermal, and optical properties of the polymers. An increase in BA contents in P(SM-co-BA) and P(SM-BA-MMA) improved the mechanical strength, but the optical properties remained the same with some exception for P(SM-co-BA). An increase in the DCP contents improved the mechanical but found losses in the optical properties.
Influence of Dilauroyl Peroxide on Mechanical and Thermal Properties of Different Polypropylene Matrices
Sirin, Kamil ; Yavuz, Mesut ; Canli, Murat ;
Polymer Korea, volume 39, issue 2, 2015, Pages 200~209
DOI : 10.7317/pk.2015.39.2.200
In this study, the influence of dilauroyl peroxide on mechanical and thermal properties of different polypropylene (PP) matrices was investigated. Polypropylene matrices, different molecular weight isotactic PP containing 0.01, 0.02, 0.04, 0.06, 0.08, and 0.1 wt% of dilauroyl peroxide (DLP) were prepared by using a single-screw extruder. The effect of the visbreaking agent (DLP) on mechanical, physical, thermal and morphological properties of different molecular weight PP had been studied. Mechanical properties (tensile strength at break point, at yield and elongation at break point), melt flow index (MFI), scanning electron microscope (SEM) and differential scanning calorimetric (DSC) analyses of these matrices were examined. Melting (
) and crystallization (
) temperatures, crystallinity ratio (%) and enthalpies were determined. The microstructure of isotactic polypropylene matrix was investigated by scanning electron microscopy (SEM). From SEM analysis, it was observed that the surface disorder increased by the increasing amount of DLP. As a result of DSC analyses, the crystallinity ratio of the PP matrices has varied between 1.64-7.27%. Mechanical properties of the matrices have been improved. Particularly, the mechanical tests of PP have given interesting results when compounded with 0.06-0.08 wt% dilauroyl peroxide (DLP). Mechanical properties and thermal decomposition processes were all changed by increasing the amount of DLP in the matrix structure.
Study on Reaction Behavior of Rigid Polyurethane Foam with Various Types and Contents of Gelling Catalysts
Eom, Se Yeon ; Lee, Hyeong Il ; Lee, Kee Yoon ;
Polymer Korea, volume 39, issue 2, 2015, Pages 210~218
DOI : 10.7317/pk.2015.39.2.210
The reaction behavior of rigid polyurethane foams were studied on the effects of gelling catalysts of amine type, such as; dimethylcyclohexyl amine (DMCHA) and of potassium type, such as; potassium octoate (PO). Rigid polyurethane foams were provided with polymeric 4,4'-diphenylmethane diisocyanate, polyester polyol, silicone surfactant, blowing agent and a few gelling catalysts. As the contents of catalyst, DMCHA increased from 0 to 2.0 g, the reaction time decreased from ca. 330 to ca. 35 sec and due to the exothermic reaction, the maximum temperature increased from ca. 217 to ca.
, respectively. As the contents of PO increased from 0 to 2.5 g, the reaction time decreased from ca. 79 to ca. 38 sec and the maximum temperature increased from ca. 182 to ca.
, respectively. The kinetic parameters were calculated and the conversions were based on the temperature rising method of adiabatic process. As the content of DMCHA increased, the rate constant
increased. But in the case of PO catalyst,
did hardly depend upon its amount, and showed us similar reaction rate constants.
Influence of Fiber Array Direction on Mechanical Interfacial Properties of Basalt Fiber-reinforced Composites
Kim, Myung-Seok ; Park, Soo-Jin ;
Polymer Korea, volume 39, issue 2, 2015, Pages 219~224
DOI : 10.7317/pk.2015.39.2.219
In this work, the effect of fiber array direction including
was investigated for mechanical properties of basalt fiber-reinforced composites. Mechanical properties of the composites were studied using interlaminar shear strength (ILSS) and critical stress intensity factor (
) measurements. The cross-section morphologies of basalt fiber-reinforced epoxy composites were observed by scanning electron microscope (SEM). Also, the surface properties of basalt fibers were determined by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). From the results, it was observed that acid treated basalt fiber-reinforced composites showed significantly higher mechanical interfacial properties than those of untreated basalt fiber-reinforced composites. These results indicated that the hydroxyl functional groups of basalt fibers lead to the improvement of the mechanical interfacial properties of basalt fibers/epoxy composites in the all array direction.
Synthesis, Characterization, Thermal Stability and Conductivity of New Schiff Base Polymer Containing Sulfur and Oxygen Bridges
Culhaoglu, Suleyman ; Kaya, Ismet ;
Polymer Korea, volume 39, issue 2, 2015, Pages 225~234
DOI : 10.7317/pk.2015.39.2.225
In this study, we proposed to synthesize thermally stable, soluble and conjugated Schiff base polymer (SbP). For this reason, a specific molecule namely 4,4'-thiodiphenol which has sulfur and oxygen bridge in its structure was used to synthesize bi-functional monomers. Bi-functional amino and carbonyl monomers namely 4,4'-[thio-bis(4,1-phenyleneoxy)] dianiline (DIA) and 4,4'-[thiobis(4,1-phenyleneoxy)]dibenzaldehyde (DIB) were prepared from the elimination reaction of 4,4'-thiodiphenol with 4-iodonitrobenzene and 4-iodobenzaldehyde, respectively. The structures of products were confirmed by elemental analysis, FTIR,
NMR techniques. The molecular weight distribution parameters of SbP were determined by size exclusion chromatography (SEC). The synthesized SbP was characterized by solubility tests, TG-DTA and DSC. Also, conductivity values of SbP and SbP-iodine complex were determined from their solid conductivity measurements. The conductivity measurements of doped and undoped SbP were carried out by Keithley 2400 electrometer at room temperature and atmospheric pressure, which were calculated via four-point probe technique. When iodine was used as a doping agent, the conductivity of SbP was observed to be increased. Optical band gap (
) of SbP was also calculated by using UV-Vis spectroscopy. It should be stressed that SbP was a semiconductor which had a potential in electronic and optoelectronic applications, with fairly low band gap. SbP was found to be thermally stable up to
. The char of SbP was observed 29.86% at
Catalyzed Transesterification Kinetics in Early Stage of Polycarbonate Melt Polymerization
Jung, Ju Yeon ; Lee, Ji Mok ; Hong, Sung Kwon ; Lee, Jin Kuk ; Jung, Hyun Min ; Kim, Yong Seok ;
Polymer Korea, volume 39, issue 2, 2015, Pages 235~239
DOI : 10.7317/pk.2015.39.2.235
In this work, we evaluated catalytic activity of LiOH,
and n-butyltin hydroxide oxide hydrate in the early stage of the melt transesterification of isosorbide and bisphenol A as diol monomers and diphenylcarbonate for the melt polymerizaiton of polycarbonate.
proved to be the most active catalyst for homopolymerization process, while the catalytic activity of LiOH was higher than the others in case of melt copolymerization depending on the catalytic mechanism and chemical structure of catalyst. We suggested that evaluation of catalytic activity can be used for selection of catalyst system in bio-based copolymerization of polycarbonate.
Observation of Interfacial Adhesion in Silica-NR Compound by Using Bifunctional Silane Coupling Agent
Lee, Jong-Young ; Kim, Sung Min ; Kim, Kwang-Jea ;
Polymer Korea, volume 39, issue 2, 2015, Pages 240~246
DOI : 10.7317/pk.2015.39.2.240
Formation of a strong 3-dimensional interfacial network structure via chemical reaction between hydroxyl group on silica surface and NR chain by the addition of bis(triethoxysilylpropyl)tetrasulfide (TESPT) into silica-filled NR compound was observed by using Py-GC/MS and SEM. Addition of TESPT into silica-filled NR compound decreased scorch time (
) due to increased sulfur content, and reduced cure rate index (CRI) via continuous reaction between sulfur atoms in TESPT, which acted as a sulfur donor, and activators and/or accelerators. Addition of TESPT in the compound improved processability and mechanical properties of the compound. Overall, we observed that the addition of TESPT into the silica-filled NR compound formed a silica-TESPT-NR network, and thus the degree of crosslinking was increased resulting in improved mechanical properties.
Poly(1,2-propylene glycol adipate) as an Environmentally Friendly Plasticizer for Poly(vinyl chloride)
Zhao, Yan ; Liang, Hongyu ; Wu, Dandan ; Bian, Junjia ; Hao, Yanping ; Zhang, Guibao ; Liu, Sanrong ; Zhang, Huiliang ; Dong, Lisong ;
Polymer Korea, volume 39, issue 2, 2015, Pages 247~255
DOI : 10.7317/pk.2015.39.2.247
Poly(1,2-propylene glycol adipate) (PPA) was used as an environmentally friendly plasticizer in flexible poly(vinyl chloride) (PVC). Thermal, mechanical, and rheological properties of the PVC/PPA blends were characterized by differential scanning calorimetry, dynamic mechanical analysis, tensile test, scanning electron microscopy and small amplitude oscillatory shear rheometry. The results showed that PPA lowered the glass transition temperature of PVC. The introduction of PPA could decrease tensile strength and Young's modulus of the PVC/PPA blends; however, elongation-at-break was dramatically increased due to the plastic deformation. The plasticization effect of PPA was also manifested by the decrease of dynamic storage modulus and viscosity in the melt state of the blends. The results indicated that PPA had a good plasticizing effect on PVC.
Effect of Photoinitiator System on Mechanical Properties and Water Sorption Behavior of Urethane Acrylate/MMT Nanocomposite by UV Radiation Curing
Kim, Ho-Gyum ; Min, Kyung-Eun ;
Polymer Korea, volume 39, issue 2, 2015, Pages 256~260
DOI : 10.7317/pk.2015.39.2.256
The addition of montmorillonite (MMT) in the UV curable polyurethane diacrylate based resins was investigated to fabricate nanocomposites with improved mechanical properties and water sorption behavior using different photoinitiator systems. As a result, it was observed that 1 wt% of clay loading fairly improved tensile resistance and water uptake behavior. It can be also confirmed that dual photoinitiator system consisted of benzyldimethyl ketal and bisacyl phosphine oxide exhibited enhanced energy absorption band 340~450 nm even with 3 wt% of MMT concentration, which may affect the curing behavior of nanocomposite especially in our UV lamp system.
Preparation and Characterization of Inclusion Complex between β-Cyclodextrin and Polylactic Acid
Nan, Song Ya ; Fang, Zhou Yu ; Jun, Zhen Wei ;
Polymer Korea, volume 39, issue 2, 2015, Pages 261~267
DOI : 10.7317/pk.2015.39.2.261
The inclusion complexes (ICs) between polylactic acid (PLA) and
-cyclodextrin (CD) were prepared by co-precipitation method in this work. The orthogonal experiments were designed to investigate the influence of different factors on the formation of inclusion complexes. The results suggested that the optimum scheme of inclusion compounds could be obtained when the feeding ratio of CD to PLA (wt%) was 20:1, stirring speed was 6 kr/min and the stirring time was 30 min. The structures and properties of the inclusion complexes were characterized by
NMR, FTIR, DSC, FT-Raman, XRD and TGA. The DSC results demonstrated that the crystallization behavior of the inclusion complexes nearly disappeared. It was found that
-CD-PLA inclusion complex had a better thermal stability compared with the neat PLA. The model of the inclusion complexes was proposed on the basis of XRD,
NMR and DSC results.
Isothermal Crystallization Kinetics of Quaternary Ammonium Group Grafted Polypropylene
Liu, Guangtian ;
Polymer Korea, volume 39, issue 2, 2015, Pages 268~274
DOI : 10.7317/pk.2015.39.2.268
In this paper, the isothermal crystallization kinetics of a functional PP (FPP) with different grafting yields (GY)-methacryloxyethyltrimethyl ammonium chloride (DMC) grafted PP were investigated by differential scanning calorimetry (DSC). The results showed that the crystallization rate of FPP (GY=4.83%) was the highest for all of the studied samples. Furthermore, for the FPP with different GY, the value of
became longer with increasing the grafting yield (GY). The possible explanation was that the quaternary ammonium groups introduced affected the crystallization process of the FPP in two opposite directions, i.e. promoting the nucleation and hindering the transport of the chain molecules towards the growing nuclei. Polarized optical micrographs showed that the DMC chains acted as nucleating agents, which accelerated the nucleation. In addition, the results showed the FPP had lower nucleation free energy than the PP. This study would be useful for designing the processing parameters of the grafted samples.
Syntheses of Colorless and Transparent Copolyimides and Comparison of the Properties of Their Copolyimides
Ju, Jieun ; Chang, Jin-Hae ;
Polymer Korea, volume 39, issue 2, 2015, Pages 275~280
DOI : 10.7317/pk.2015.39.2.275
Two series of copolyimides (Co-PIs) were prepared by reacting 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 1,2,4,5-benzentetra carboxylic dianhydride (pyromellitic dianhydride) (PMDA), as dianhydrides based on 4,4'-biphthalic anhydride (BPA) and 2,2'-bis(trifluoromethyl)benzidine (TFB) by using thermal- and chemical imidizations. Co-PIs films with different dianhydride monomer compositions were compared in terms of their thermal properties and optical transparencies. The addition of PMDA was more effective than the addition of 6FDA for improving the thermal properties. Meanwhile, 6FDA is more effective in optical transparencies.
Effect of Crosslinking Agent on Adhesion Properties of UV Curable 2-EHA/AA Pressure Sensitive Adhesive
Kim, Ho-Gyum ; Min, Kyung-Eun ;
Polymer Korea, volume 39, issue 2, 2015, Pages 281~286
DOI : 10.7317/pk.2015.39.2.281
UV-cured acrylic copolymer pressure sensitive adhesive (PSA) having different amounts of crosslinking agents were prepared and adhesion properties were investigated. 0.01 wt% of MMT clay was dispersed in 2-ethylhexyl acrylate (2-EHA)/acrylic acid (AA) monomer mixture containing 0, 0.05, 0.1 and 0.3 wt% 1,6-hexandiol diacrylate (HDDA) for crosslinking. It was investigated that the curing behavior and surface chemistry of PSAs were merely affected by the presence of MMT clays. On the other hand, adhesive properties were influenced by the MMT addition; a cohesive failure was restrained due to improved molecular elasticity even in uncrosslinked acrylic PSAs. However, it was also appeared that combination of 0.3 wt% crosslinking agent and MMT loading might result in the damage of adhesion properties of PSAs possibly due to the lack of chain flexibility. In our studies, it is suggested that the 2-EHA/AA PSAs incorporating 0.01 wt% of MMT and crosslinked with 0.05 wt% of HDDA exhibited the balanced adhesion properties without severe cohesive failure during strip.
Microstructure and Thermal Characteristics of Bio-based Terpolymer Made from Terephthalic Acid with Ethylene Glycol, 1,4-Cyclohexane Dimethanol, and Isosorbide
Lee, Sangmook ; Kim, Sungki ; Hong, In-Kwon ;
Polymer Korea, volume 39, issue 2, 2015, Pages 287~292
DOI : 10.7317/pk.2015.39.2.287
Characterization of a series of bio-based terpolymers containing various amounts of ethylene glycol, 1,4-cyclohexylene dimethanol, and isosorbide units were studied by
NMR. The NMR results revealed that they had all random microstructures and that their sequence distribution was affected by the content of isosorbide. From DSC data for the terpolymer series investigated, it was observed that the glass transition temperature increased mainly as the content of isosorbide increased. The glass transition temperatures of terpolymers were estimated from the composition by extended Fox equation.
Preparation, Morphology and Electrical Conductivity of Polystyrene/Polydopamine- Carbon Nanotube Microcellular Foams via High Internal Phase Emulsion Polymerization
Kim, Haseung ; Na, Hyo Yeol ; Lee, Jong Heon ; Lee, Seong Jae ;
Polymer Korea, volume 39, issue 2, 2015, Pages 293~299
DOI : 10.7317/pk.2015.39.2.293
Conductive microcellular foams consisted of polystrene (PS) and polydopamine-coated carbon nanotube (PDA-CNT) were prepared via high internal phase emulsion (HIPE) polymerization and their morphology and electrical conductivity were investigated. CNT as a conductive nanofiller was modified to PDA-CNT by coating with hydrophilic PDA on the surface of CNT to increase aqueous phase dispersion and emulsion stability. It was possible to prepare the HIPEs having higher PDA-CNT content and the resultant foams having improved conductivity due to its good dispersion. The foams showed the morphology of interconnected cell structure. As PDA-CNT content increased, yield stress and storage modulus increased and cell size reduced. The PDA-CNT content showing electrical percolation threshold was ca. 0.58 wt% and the conductivity at PDA-CNT content of 5 wt% was increased to
Quantitative Analysis of Grafted Methacrylate Groups by Michael Addition Reaction between Primary and Secondary Amino Groups on the Silica Nanoparticle Surface with 3-(Acryloyloxy)-2-Hydroxypropyl Methacrylate
Lee, Sangmi ; Ha, KiRyong ;
Polymer Korea, volume 39, issue 2, 2015, Pages 300~310
DOI : 10.7317/pk.2015.39.2.300
In this study, we modified silica nanoparticles with N-[3-(trimethoxysilyl)propyl]ethylenediamine (TPED) silane coupling agent, which has one primary and one secondary amino groups in a molecule, to introduce amino groups on the silica surface. After modification of silica, we used 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) to introduce methacrylate groups by Michael addition reaction. We found about 30% of N-H groups on the TPED modified silica surface reacted with acrylate groups of AHM compared to about 85% of reaction between N-H groups of pure TPED with acrylate groups of pure AHM. This lower degree of Michael addition reaction for heterogeneous reaction between N-H groups on the solid TPED modified silica and liquid AHM compared to homogeneous reaction between pure liquid TPED and pure liquid AHM may be caused by lower mobility of grafted amino groups of TPED moiety and higher steric hindrance caused by solid silica particles.
Preparation of Silicon-Based Hybrid Gels with POSS Additives and Their Application to LED Encapsulants
Eun, Hee-Chun ; Im, Hee-Eun ; Lee, Yun Sang ; Kwark, Young-Je ;
Polymer Korea, volume 39, issue 2, 2015, Pages 311~316
DOI : 10.7317/pk.2015.39.2.311
Densely structured polyhedral oligomeric silsesquioxane (POSS) was employed as an additive to enhance hardness of silicon-based hybrid gels for LED encapsulants. To improve the miscibility of POSS and polysiloxane resin, alkyl or oligosiloxane branches were introduced to POSS moiety. Platinum-catalyzed hydrosilylation reactions were used to attach branches of 1-decanol, 9-decen-1-ol, and vinyl-terminated oligosiloxane to the POSS molecules. Alkyl-branched POSSs (decyl-POSS and decenyl-POSS) were immiscibile with polysiloxane resin and generated gels with low transparency and low hardness values. On the other hand, oligosiloxane-branched POSS (Siloxy-POSS) showed good miscibility with polysiloxane resin to give gels with high transparency. However, the prepared gels did not show noticeable improvement in hardness compared to the gels without the POSS additive.
Performance Analysis of Pressure-retarded Osmosis Power Using Biomimetic Aquaporin Membrane
Choi, Wook ; Bae, Harim ; Lee, Hyung-Keun ; Lee, Jonghwi ; Kim, Jong Hak ; Park, Chul Ho ;
Polymer Korea, volume 39, issue 2, 2015, Pages 317~322
DOI : 10.7317/pk.2015.39.2.317
Salinity gradient power is a system which sustainably generates electricity for 24 hrs, if the system is constructed at a certain place where both seawater and river water are consistently pumped. Since power is critically determined by the water flux and the salt rejection, a membrane of water-semipermeable aquaporin protein in cell membranes was studied for pressure-retarded osmosis. NaCl was used as a salt, and
was used as a candidate to check the ion selectivity. The water flux of biomimetic aquaporin membranes was negligible at a concentration below 2M. Also, there is no remarkable dependence of water flux and ion selectivity on concentrations higher than 3M. Therefore, the biomimetic aquaporin membrane could not be applied into pressure-retarded osmosis; however, if a membrane could overcome the current limitations, the properties shown by natural cells could be accomplished.
Synthesis and Characterization of Porous Poly(ε-caprolactone)/Silica Nanocomposites
Son, Siwon ; Choi, Ji-Eun ; Cho, Hun ; Kang, DaeJun ; Lee, Deuk Yong ; Kim, Jin-Tae ; Jang, Ju-Woong ;
Polymer Korea, volume 39, issue 2, 2015, Pages 323~328
DOI : 10.7317/pk.2015.39.2.323
-caprolactone) (PCL) nanofibers and PCL/silica membranes were synthesized by sol-gel derived electrospinning and casting, respectively. Smooth PCL nanofibers were obtained from the precursor containing N,N-dimethylformamide (DMF). PCL/silica membranes were prepared by varying the tetraethyl orthosilicate (TEOS) contents from 0 to 40 vol% to investigate the effect of silica addition on mechanical properties and cytotoxicity of the membranes. Although the strength of the membranes decreased from 12 to 8 MPa with increasing the silica content, the strength remained almost constant 7 weeks after dipping in phosphate buffered saline solution (PBS). The strength reduction was attributed to the presence of a patterned surface pores and micro-pores present in the walls between pores. The crystal structure of the membranes was orthorhombic and the crystallite size decreased from 57 to 18 nm with increasing the silica content. From the agar overlay test, the PCL/silica membranes exhibited neither deformation and discoloration nor lysis of L-929 fibroblast cells.
Preparation of MWCNTs/Poly(methyl methacrylate) Composite Particles via the Emulsion Polymerization of Methyl Methacrylate Using MWCNTs Modified by Silanization Reaction and Their Morphological Characteristics
Kwon, Jaebeom ; Park, Seonghwan ; Kim, Sunghoon ; Jo, Jieun ; Han, Changwoo ; Ha, KiRyong ;
Polymer Korea, volume 39, issue 2, 2015, Pages 329~337
DOI : 10.7317/pk.2015.39.2.329
In this study, multi-walled carbon nanotubes (MWCNTs) were oxidized with a mixture of nitric acid and sulfuric acid. After oxidation, oxidized MWCNTs were treated with thionyl chloride (
) and 1,4-butanediol (BD) in sequence at room temperature to introduce hydroxyl groups on the surface of MWCNTs. The prepared MWCNT-OH was silanized with 3-methacryloxypropyltrimethoxylsilane (MPTMS) to make MWCNT-MPTMS. The MWCNT-MPTMS was used as fillers in emulsion polymerization to make MWCNT-MPTMS/PMMA composite particles with 3 kinds of emulsifiers, hexadecyltrimethylammoniumbromide (CTAB) as a cationic, sodium dodecylbenzene sulfonate (SDBS) as an anionic and polyethylene glycol tert-octylphenyl ether (Triton X-114) as a nonionic emulsifier. Morphologies of composite emulsions were confirmed by a particle size analyzer (PSA) and a scanning electron microscope (SEM). Morphologies of emulsion polymerized MWCNT-MPTMS/PMMA with SDBS showed more uniform particle size distribution compared to those of other two emulsifiers used emulsions. MWCNT-MPTMS/PMMA showed
compared to pristine MWCNT/PMMA due to covalent bond formation at interface of MWCNT-MPTMS and PMMA.
Synthesis of Aminated Poly(ether imide) for the Preparation of Bi-polar Membranes and Their Application to Hypochlorite Production through the Surface Direct Fluorination
Kim, Cheong Seek ; Kang, SuYeon ; Rhim, Ji Won ; Park, Soo-Gil ;
Polymer Korea, volume 39, issue 2, 2015, Pages 338~345
DOI : 10.7317/pk.2015.39.2.338
Poly(phenylene oxide) (PPO) and polyether imide (PEI) were sulfonated and aminated to create sulfonated poly(phenylene oxide) (SPPO) and aminated polyether imide (APEI), respectively. Characterization of the SPPO and APEI were performed via measurements of FTIR, thermogravimetry (TGA), swelling degree, ion exchange capacity (IEC), and ion conductivity. Next, the surfaces of these membranes were modified by surface fluorination at room temperature. The surface fluorinated SPPO and APEI membranes underwent characterization again for the mentioned measurements to determine any differences. The 3 types of bi-polar membranes were prepared by varying the IEC of the APEI at a fixed SPPO IEC value, which were applied to the low and high NaCl concentration of feed solution at the different current density, respectively. The hypochlorite concentration derived from the surface fluorinated membranes was dependent on the IEC of the APEI and ranged from 491 to 692 ppm at
. At low current density of
, the hypochlorite concentrations ranged from 18 to 28 ppm for the 4 hrs surface fluorinated membranes and their durability increased greatly.
A Study on the Control of Microstructures of Polyalphaolefins via Cationic Polymerization
Ko, Young Soo ; Kwon, Wan-Seop ; No, Myoung-Han ; Yim, Jin-Heong ;
Polymer Korea, volume 39, issue 2, 2015, Pages 346~352
DOI : 10.7317/pk.2015.39.2.346
Polyalphaolefin (PAO) is a synthetic lubricant that is superior to mineral-based lubricants in the terms of physical and chemical characteristics such as low pour point, high viscosity index (VI), and thermal and oxidation stability. Several kinds of PAOs have been synthesized by using 1-pentene, 1-hexene, 1-octene, or 1-dodecene as monomer with three kinds of aluminum-based Lewis acid catalysts via cationic polymerization. The control of the catalytic performance and physical properties of PAO such like molecular weight, kinematic viscosity, pour point, and viscosity index was done by changing polymerization parameters. The alkyl aluminum halide-based catalysts show better catalytic activity than that of the conventional
catalyst. The microstructure of PAO was investigated by means of TOF-MS (time of flightmass spectroscopy) analysis in order to elucidate the correlation between the performances of the lubricant (VI, pour point) and the molecular structure of PAO. The VI of PAO increases with increases in the carbon number of
-olefin. In other words, the performances of PAO as a lubricant strongly depended on the branch length of PAO.
Aqueous-Based Photocurrent Generation by Fluorescence Resonance Energy Transfer between Conjugated Oligoelectrolytes and Erythrosin B
Kang, Insung ; Park, Jonghyup ; Jo, Hyunjin ; Park, Juhyun ;
Polymer Korea, volume 39, issue 2, 2015, Pages 353~358
DOI : 10.7317/pk.2015.39.2.353
Aqueous-based, environmentally friendly photocurrent generation has been highlighted to produce electricity by mimicking photosynthesis in nature. We fabricated a photocurrent generation system using a conjugated oligoelectrolyte (COE) assembled in lipid vesicles and a fluorescence dye, and investigated the fluorescence resonance energy transfer (FRET) between two species and the influence of FRET on the photocurrent generation. The FRET efficiency from the electron donor, COE, to the electron acceptor, the dye, increased with the dye concentrations, but the photocurrent increased and then decreased with the dye concentrations. We discussed about the role of FRET and electron shuttles over the variation of photocurrent.