Theoretical and Experimental Investigation of Limiting Diffusion Current in the Systems with Modified Perfluorinated Membranes Containing Sulfonic Acid Groups

Generating acid–base interactions between sulfonic acid groups in a proton exchange membrane (PEM) and the incorporation of basic groups are effective approaches to improving the physicochemical properties of a membrane.

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Synthesis and characterisation of novel functional polyolefin containing sulfonic acid groups

European Polymer Journal ◽

10.1016/j.eurpolymj.2007.11.017 ◽

2008 ◽

Vol 44 (2) ◽

pp. 475-482 ◽

Cited By ~ 6

Author(s):

Yi Zheng ◽

Li Pan ◽

Yan-Guo Li ◽

Yue-Sheng Li

Keyword(s):

Sulfonic Acid ◽

Sulfonic Acid Groups

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Synthesis of soluble sulfonated polybenzimidazoles derived from 2-sulfonate terephthalic acid

e-Polymers ◽

10.1515/epoly.2008.8.1.851 ◽

2008 ◽

Vol 8 (1) ◽

Author(s):

Qunying Wu ◽

Guyu Xiao ◽

Deyue Yan

Keyword(s):

Terephthalic Acid ◽

Sulfonic Acid ◽

Strong Acid ◽

High Thermal Stability ◽

Swelling Ratio ◽

Solution Casting ◽

Direct Polycondensation ◽

Acid Base ◽

Resistance To Oxidation ◽

Sulfonic Acid Groups

Abstract2-Sulfonate p-terephthalic acid (sTA) was synthesized, and sulfonated polybenzimidazoles (sPBI) were prepared by direct polycondensation of 3,3’- diaminobenzidine (DAB) and sTA with 4,4’-oxybis(benzoic acid) (OBBA) or 2,2’- bis(4-carboxylphenyl)-hexafluoropropane (BCHFP). Thus the ether groups and hexafluoroisopropylidene units were incorporated into the backbone of the sPBI in order to improve the flexibility and solubility. The sPBI based on OBBA showed poor solubility, while the sPBI containing hexafluoroisopropylidene units were soluble in common solvents. sPBI-20 ~ sPBI-60 could form tough and transparent membranes by solution casting. sPBI indicated high thermal stability, the 5% weight loss temperature (T5%) which was higher than 520°C, decreased with the increase of degree of sulfonation. sPBI-20 ~ sPBI-60 showed no glass transition at temperatures lower than 380°C. In addition, sPBI showed low water uptake, low swelling ratio as well as excellent resistance to oxidation. But sPBI exhibited low proton conductivity because of the strong acid-base interactions between basic benzimidazole and sulfonic acid groups.

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Estimation of the exchange current density and comparative analysis of morphology of electrochemically produced lead and zinc deposits

Journal of the Serbian Chemical Society ◽

10.2298/jsc161114029n ◽

2017 ◽

Vol 82 (5) ◽

pp. 539-550

Author(s):

Nebojsa Nikolic ◽

Predrag Zivkovic ◽

Goran Brankovic ◽

Miomir Pavlovic

Keyword(s):

Current Density ◽

Exchange Current ◽

Exchange Current Density ◽

Diffusion Current ◽

Electron Microscopic ◽

Zinc Electrodeposition ◽

Lead And Zinc ◽

Current Densities ◽

Limiting Diffusion Current ◽

Zinc Deposits

The processes of lead and zinc electrodeposition from the very dilute electrolytes were compared by the analysis of polarization characteristics and by the scanning electron microscopic (SEM) analysis of the morphology of the deposits obtained in the galvanostatic regime of electrolysis. The exchange current densities for lead and zinc were estimated by comparison of experimentally obtained polarization curves with the simulated ones obtained for the different the exchange current density to the limiting diffusion current density ratios. Using this way for the estimation of the exchange current density, it is shown that the exchange current density for Pb was more than 1300 times higher than the one for Zn. In this way, it is confirmed that the Pb electrodeposition processes are considerably faster than the Zn electrodeposition processes. The difference in the rate of electrochemical processes was confirmed by a comparison of morphologies of lead and zinc deposits obtained at current densities which corresponded to 0.25 and 0.50 values of the limiting diffusion current densities.

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