DETERMINATION OF SOME ELECTRICAL PARAMETERS FOR 2 NOVEL ALIPHATIC-AROMATIC POLYAMIDE MEMBRANES

The effect of the chemical structure in the electrical response (membr ane potential, Delta phi, salt diffusion, D-s, resistance, R(m), and c apacitance, C-m) of two new aliphatic-aromatic polyamide membranes is considered. They are poly(ether-amide)s with an oxygen atom difference . Measurements were carried out with NaCl and MgCl2 solutions at diffe rent concentrations. Equivalent circuits were determined by impedance spectroscopy and a parallel R(m)C(m) association was obtained for both membranes and electrolytes. Under identical external conditions, sign ificant differences for the membrane resistance values were found as a function of the membrane chemical nature, but the capacitance hardly depends on both membrane and electrolyte. From Delta phi and R(m) valu es some membrane characteristic parameters such as transport numbers a nd ionic diffusion coefficients were determined. Concentration depende nce of all these parameters was also studied.