• Membrane Journal
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• v.19 no.2
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• pp.89-95
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• 2009

A comb-like copolymer consisting of a poly(vinyl chloride) backbone and poly(hydroxy ethyl acrylate) side chains, i.e. PVC-g-PHEA, was synthesized through atom transfer radical polymerization (ATRP). This comb-like copolymer was crosslinked with 4,5-imidazole dicarboxylic acid (IDA) via the esterification of the -OH groups of PHEA in the graft copolymer and the -COOH groups of IDA. Upon doping with phosphoric acid (PA, $H_3PO_4$) to form imidazole-PA complexes, the proton conductivity of the membranes continuously increased with increasing PA content. A maximum proton conductivity of 0.011 S/cm was achieved at $100^{\circ}C$ under anhydrous conditions. The PVC-g-PHEA/IDA/PA complex membranes exhibited good mechanical properties, i.e. 575 MPa of Young's modulus, as determined by a universal testing machine (UTM). Thermal gravimetric analysis (TGA) shows that the membranes were thermally stable up to $200^{\circ}C$.

• Membrane Journal
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• v.3 no.3
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• pp.126-135
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• 1993

Perchlorate ion-selective PVC membrane electrode responsive to $10^{-6}M$ was developed by incorporating the ion-pair complex of perchlorate with the quaternary ammonium salts as a active material. The effect of chemical structure, the content of active material, the kinds of plasticizers, and the membrane thickness on the electrode characteristics such as the linear response range and Nernstian slope of the electrode were studied. With the results, the useful pH range and the selectivity coefficients to various interfering anions were compared and investigated. It was obtained that the effect of the chemical structure of an active material on the electrode characteristics was improved with increasing the alkyl chain length of the quarternary ammonium salts in the ascending order of Aliquat 336P, TOAP, TDAP, and TDDAP. The electrode characteristics was improved with the decrease of the active material content below the optimum membrane composition, and DBP was the best as a plasticizer. The optimum membrane composition was 9.09wt% of TDDAP, 30.3wt% of PVC, and 60.6wt% of ptasticizer(DBP). And the optimum membrane thickness was0.45mm at this composition. Under the above condition, thelinear response ranger was $10^{-1}~1.2 {\times} 10^{-6}M$, and the detection limit was $5.1{\times}10^{-7}M$ with the Nernstian slope of 57mV/decade of activity of perchlorate ion. The electrode potential was stable within the pH range from 4 to 11. The selectivity coefficient was as shown below : $SCN^->I^->NO_3^->Br^->ClO_3^->F^->Cl^->SO_4^{2-}$

• Membrane Journal
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• v.6 no.4
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• pp.265-272
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• 1996

The (polymer/carrier) composite membranes for separating the metallic ion have been prepared by the water cast-method. The morphology of these membranes was affected by the physical properties of the spreading solution. The surface tension of the (polymer/18-crown-6) composite solution was decreased with increasing the concentration of 18-crown-6 compound and the surface tension of polymer solution decreased the following order PVC>PS>CA. The viscosity of CA solution decreased with increasing the contents of the 18-crown-6 compound, but PVC and PS solutions showed no significance changes according as the concentration of 18-crown-6 compound. In the composite solutions, the spreading ability was improved by' the cyclic 18-crown-6 molecules which acted as an electric buffer and diminished the intermolecular force between the polymer chains. The (polymer/18-crown-6) composite membrane was more uniform than that of the mono polymer membrane on the coagulation state of polymer, and the top and bottom sides of membrane showed also the more smooth structure according as the concentration increment of 18-crown-6 molecule.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.579-584
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• 2005

The 3-[(2-furylmethylene)amino]-2-thioxo-1,3-thiazolidin-4-one (FTT) was used as an excellent ionophore in construction of a $Zn^{2+}$ PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 62% nitrobenzen (NB), 3% FTT and 5% sodium tetraphenyl borate (TBP). This membrane sensor shows very good selectivity and sensitivity towards $Zn^{2+}$ over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The membrane sensor revealed a great enhancement in selectivity coefficients for $Zn^{2+}$ ions, in comparison to the previously reported $Zn^{2+}$ membrane sensors. Theoretical studies also showed the selective interaction of TFF and $Zn^{2+}$ ions. The proposed membrane sensor exhibits a Nernstian behavior (with slope of 29.3 ${\pm}$ 0.3 mV per decade) over a wide concentration range (1.0 ${\times}$ $10^{-6}$-1.0 ${\times}$ $10^{-2}$) with a detection limit of 8.5 ${\times}$ $10^{-7}$ M (52 ng mL$^{-1}$). It shows relatively fast response time, in the whole concentration range ($\lt$ 20 s), and can be used for at least 10 weeks in a pH range of 3.0-7.0. The proposed membrane sensor was successfully used in direct determination of $Zn^{2+}$ ions in wastewater of industrial zinc electroplating companies, and also as an indicator electrode in titration with EDTA.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.47-59
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• 1995

The perchlorate, thiocyanate, and nitrate ion-selective PVC membrance electrode for measuring hazardous anion in waste water were developed by incorporating the quaternary ammonium salts as active material. Ion-selective characteristics in waste water were studied by the useful pH range, the selective coefficients to various interfering anions, and the stability of electrode potential. DBP was best as a plasticizer. The effect of the membrane thickness on the electrode characteristics was improved with decreasing the membrane thickness, but below the optimum membrane thickness the electrode exhibited an inverse trend. The electrode potential of perchlorate, thiocyanate, and nitrate electrode with TDDA, as active material, was stable within the pH range 4-11, 3-12, and 4-10 repectively. And the long-term potential stability of these electrodes were 3.0, 3.5, and 3.5 months respectively. The order of the selectivity coefficients was as shown below ; $ClO_4{^-}$ > $SCN^-$ > $I^-$ > $NO_3{^-}$ > $Br^-$ > $CN^-$ > $F^-$ > $Cl^-$ > $Ac^-$ > $H_2PO_4{^-}$, $SO_4{^-}$.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.388-398
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• 1989

A continuous-automated method for the determination of nitrite ion using gas-sensing membrane electrode was developed. The pH electrode of tubular PVC membrane type was used as a detector of this system. The slope of linear response of the electrode measured at optimum conditions for the continuous-automated determination of nitrite ion was 63.5 mV/decade. The concentration range of linear response and detection limit were 2.5 ${\times}10^{-4}{\sim}\;7.5{\times}10^{-2}$M and $8.0{\times}10^{-5}$M, respectively. This detection system was not only less interfering to acidic gas species than other methods but also less time consumable for determination.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3088-3092
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• 2013

A novel PVC membrane sensor for perindopril based on perindopril-phosphotungstate ion pair complex was prepared. The influence of membrane composition (i.e. percent of PVC, plasticizer, ion-pair complex, and kind of plasticizer), inner solution, pH of test solution and foreign cations on the electrode performance was investigated. The optimized membrane demonstrates Nernstian response ($30.9{\pm}1.0$ mV per decade) for perindopril cations over a wide linear range from $9.0{\times}10^{-7}$ to $1{\times}10^{-2}$ M at $25^{\circ}C$. The potentiometric response is independent of the pH in the range of 4.0-9.5. The proposed sensor has the advantages of easy preparation, fast response time. The selectivity coefficients indicate excellent selectivity for perindopril over many common cations (e.g., $Na^+$, $K^+$, $Mg^{2+}$, $Cu^{2+}$, $Ni^{2+}$, rhamnose, maltose, glycine and benzamide. The practical applications of this electrode was demonstrated by measuring the concentrations of perindopril in pure solutions and pharmaceutical preparations with satisfactory results.

• Membrane Journal
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• v.19 no.2
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• pp.96-103
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• 2009

A series of organic-inorganic composite membranes from poly(vinyl chloride) (PVC) graft copolymer electrolyte and heteropolyacid (HPA) were prepared for proton conducting membranes. First, poly(vinyl chloride)-g-poly(styrene sulfonic acid) (PVC-g-PSSA) was synthesized by atom transfer radical polymerization (ATRP) using direct initiation of the secondary chlorines of PVC. HPA nanoparticles were then incorporated into the PVC-g-PSSA graft copolymer though the hydrogen bonding interactions, as confirmed by FT-IR spectroscopy. The proton conductivity of the composite membranes increased from 0.049 to 0.068 S/cm at room temperature with HPA contents up to 0.3 weight traction of HPA, presumably due to both the intrinsic conductivity of HPA particles and the enhanced acidity of the sulfonic acid of the graft copolymer. The water uptake decreased from 130 to 84% with the increase of HPA contents up to 0.45 of HPA weight traction, resulting from the decrease in number of water absorption sites due to hydrogen bonding interaction between the HPA particles and the polymer matrix. Thermal gravimetric analysis (TGA) demonstrated the enhancement of thermal stabilities of the composite membranes with increasing concentration of HPA.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.3
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• pp.219-226
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• 1995

The wave interaction with flexible membrane such as PVC and PU fabrics is studied to prove its applicability to portable breakwaters. To analyze the wave deformation due to the flexible membrane. eigen-function expansion method is employed. The fluid domain is seperated into two regions. The velocity potential in each regions and the deformation of membrane are coupled by the body boundary conditions. Herein the deformation of membrane is obtained by solving the membrane equation. As a numerical example, transmission and reflection coefficients according to the change of several design parameters such as tensile force. mooring line stiffness and membrane height are investigated. It is found that the efficiency of flexible membrane breakwater is significantly affected by these design parameters. The angle of incident wave is an important role to the performance of breakwater. Finally we conclude that flexible membrane can be used to engineering material for the future breakwaters.

• Membrane Journal
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• v.18 no.4
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• pp.261-267
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• 2008

A graft copolymer consisting of poly(vinyl chloride) (PVC) backbone and poly(hydroxyethyl acrylate) (PHEA) side chains was synthesized via atom transfer radical polymerization (ATRP). Direct initiation of the secondary chlorines of PVC facilitates grafting of hydrophilic PHEA monomer. This graft copolymer, i.e. PVC-g-PHEA was cross-linked with sulfosuccinic acid (SA) via the esterification reaction between -OH of the graft copolymer and -COOH of SA, as confirmed by FT-IR spectroscopy. Ion exchange capacity (IEC) continuously increased to 0.87meq/g with increasing concentrations of SA, due to the increasing portion of charged groups in the membrane. However, the water uptake increased up to 20.0wt% of SA concentration above which it decreased monotonically. The membrane also exhibited a maximum proton conductivity of 0.025 S/cm at 20.0 wt% of SA concentration, which is presumably due to competitive effect between the increase of ionic sites and the crosslinking reaction.