Conductivity and ion exchange capacity

They have high acidity with high conductivity (and ion-exchange capacity) when wet. 

Figure 3 shows the relation between electric conductivity and ion exchange capacity of membranes produced from the PVEX monomers with m = 0 and 1 which are indicated by formula (2). 

In the present stndy, as part of an ongoing program to develop new electrolytes with fnrther higher proton conductivity at lower operating temperatnre near room temperature and nnderstand the proton behavior on the decomposed chains in the polymer, garmna-ray irradiation to the membranes was examined in air at room temperatnre and the radiation effects on the protonic condnction process were investigated by proton conductivity, optical absorption and ion-exchange capacity measnrements. 

Figure 21. Dependence of membrane conductivity on ion-exchange capacity for perfluorosulfonate and carboxylate membranes, in 35% NaOH, at 90°C. (Ref. 146 reprinted by permission of the publisher, The Electrochemical Society, Inc.)...

Figure 3. Electric conductivity in 0.1 N NaOH at 25° C and ion exchange capacity...

Swelling water uptake, electric conductivity, and transport number of the membranes are measured as a function of the ion-exchange capacity (lEC). lEC has been estimated in terms of... 

Yang, Y. S., Shi, Z. Q. and Holdcroft, S. 2004. Synthesis of sulfonated polysul-fone-block-PVDF copolymers Enhancement of proton conductivity in low ion exchange capacity membranes. Macromolecules 37 1678-1681. 

Conductivity detector is the most common and useful detector in ion exchange chromatography. However UV and other detectors can also be useful [10]. Conductivity detection gives excellent sensitivity when the conductance of the eluted solute ion is measured in an eluent of low background conductance. Therefore when conductivity detection is used dilute eluents should be preferred and in order for such eluents, to act as effective competing ions, the ion exchange capacity of the column should be low [1]. 

If the ion-exchange capacity of the separator column is sufficiently low and if dilute eluent is used, ion suppression is unnecessary. Also, anions of weak acids, such as borate, silicate, sulfide, and cyanide, cannot be determined with ion suppression, because these anions are converted into very weakly conductive products (such as H2S). 

Strongly basic anion exchange resins are sensitive to organic matter (particularly humic substances), with attendant decreases in their ion exchange capacity, pH, and active depth, as well as with increases in the amount of water required for the washing operation, and in the conductivity of the final solution. 

It was also revealed by means of ultraviolet, visible and infrared optical absorption and hydrogen ion-exchange capacity measurements that the radiation induced defects such as fluorocarbon and peroxy radicals, and C=0 including in carbonyl groups were related to the new proton conduction processes. The modification of the hydrogen absorption characteristics due to the radiation induced defects in the near sttrface regions induces the enhancement of the proton conductivity. 

Several methods have been used to produce different types of OL-1, OMS-1, and OMS-2 materials. The materials that are produced by various methods lead to vastly different materials, that have unique chemical and physical properties. Some of the properties that can be controlled are particle size, color, morphology, average manganese oxidation state, thermal stability, ion-exchange capacity, electrical conductivity, magnetic properties, crystallinity, defect density, desorption of oxygen, and catalytic properties. Table IV summarizes 16 different classes of OMS-1, OMS-2, OL-1, and amorphous manganese oxide (AMO) materials that we have prepared. These materials are separated into different classes because they show different crystalline, chemical and physical properties. For the case of OMS-1 these materials... 

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