Cation-exchange polymer

Note 3 Depending on which ion can be exchanged, the polymer is referred to as an anion exchange polymer or cation exchange polymer. 

Fluoroplastic MF-4SK. cation exchange polymer (analogous to Nafion) CdS, ZnS, and SnS2 particles immobilized in the polymer... 

Electron hopping is not the only mechanism by which a multilayer film containing an electroactive species can be electrochemically oxidized or reduced. Consider an electrode surface that has been coated with a film of the cation-exchange polymer Nafion (Table 13.2). Let us assume that the electroactive cation Fe3+ has been ion-exchanged into this Nafion film (e.g., Eq. 13.4). In principle, the Fe3+ in this film can be reduced via the following redox reaction ... 

Grot, W. (1975) Perfluorinated cation exchange polymers. Chemie Ingenieur Technik, 47, 617. 

Peptide Purification At pH 7.0, in what order would the following three peptides be eluted from a column filled with a cation-exchange polymer Their amino acid compositions are ... 

The idea of using an ion-conductive polymeric membrane as a gas-electron barrier in a fuel cell was first conceived by William T. Grubb, Jr. (General Electric Company) in 1955. - In his classic patent, Grubb described the use of Amber-plex C-1, a cation exchange polymer membrane from Rohm and Haas, to build a prototype H2-air PEM fuel cell (known in those days as a solid-polymer electrolyte fuel cell). Today, the most widely used membrane electrolyte is DuPont s Nation... 

Wodzki R, Swiatkowski M, Pretula J, and Kaluzynski K. Poly[poly(ox3qjropylene) phosphate] macroionophores for transport and separation of cations in a hybrid Cation-exchange polymer and hquid membrane system. J. Appl Polym Sci, 2004 93(3) 1436-1445. 

Boyd, G. Soldanho, B.A. Self diffusion of cations in and through sulfonated polystyrene cation exchange polymers. J. Am. Chem. Soc. 1953, 75, 6091. 

MHS) consisted of two cation-exchange polymer membranes Nafion-120. The feed chamber contained the equimolar solutions of Zn(II), Cu(II), Mn(II), Ni(II), and Co(II) sulfates, 2 x 10 mol/dm each the strip was 0.1 niol/dm solution of sulfuric acid. The feed and strip solutions were circulated using a multichannel peristaltic pump. Experiments showed that after a transient period (up to 15 h), the output fluxes have attained their constant value and assumed to be quasistationary. Examples of the values of the fluxes are listed in Table 6.9. 

In Table 14-1 a Nafion 1 (sulfonated perfluoroalkyl polyanion polymer) membrane is often used since it is a stable cation-exchange polymer able to adsorb cationic compounds easily. A Nafion membrane is composed of hydrophilic columns incorporating anionic sulfonate groups, hydrophobic columns composed of main chains, and interlayer regions between the hydrophilic and hydrophobic columns. When a cationic substrate is adsorbed from an aqueous solution, the adsorbed material is located only in the hydrophilic columns or interlayer regions, so that a real local concentration of... 

The most important components in a fuel cell are the Membrane Electrolyte Assembly (MEA) and the bipolar plates. The MEA usually consists of an electrolyte membrane, which is coated with catalytically active platinum-electrodes and a gas diffusion layer of hydrophobic graphite. As the electrolyte membrane cation exchange polymers are used. A crucial break-through was reached here by the employment of fluoridated polymers. The market leader here is Nation developed by the company Dupont. 

Song MK, Park SB, Kim YT, Rhee HW, Kim J (2003) Nanocomposite polymer membrane based on cation exchange polymer and nano-dispersed clay sheets. Mol Cryst Liq Crys 407 15-23... 

The need for high electronic conductivity has meant that work has focused on the use of the so called conducting polymers, exemplified by polypyrrole, polyaniline and polythiophene (Structures 1 to 3). These materials must be in their p-doped (partially oxidized) states (right hand side of eq. 1, for example) to exhibit sufficient electronic conductivity. Unfortunately, the p-doped polymers are cationic and will therefore tend to exclude the protons needed for the fuel cell reactions. To circumvent this problem, composites of conducting polymers with cation exchange polymers have been used. Thus p-doped polypyrrole / poly(styrene-4-sulphonate) (PSS), for example, exhibits both proton and electron conductivity (8). 

Blending of cation-exchange polymers which show a specific interaction with the cation exchange group. 

B. Kolarz, Porous Carboxylic Cation Exchangers, Polymer 2 (1975). Cation Exchanger Styrene Divinylbenzene. Macroporous Carboxy Cation Exchanger. IPNs based on PS. 

Cation-Exchange Polymer with Carboxyl Groups... 

FIGURE 3.6. The interface between a cation exchange polymer and an electrolyte. Fixed charges on the polymer chains are shown as (-), mobile cations, mobile anions, 4>-electric potential, (negative) Donnan potential. 

FIGURE 3.7. Equilibrium concentrations of anions and cations in two cation exchange polymers (a> = —1) in contact with electrolyte of the K K type of concentration c. The A< o is the Donnan potential c, is the concentration of negative fixed ions in the polymer. 

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