Permselectivity and Conductivity of Membranes Based on Sulfonated Naphthalenic Copolyimides

Abstract

A series of sulfonated diamines were synthesized which were further used to obtain relevant sulfonated naphthalenic copolyimides. Tough and ductile membranes were cast from solutions of the copolyimides in dimethylsulfoxide, which exhibit high ion-exchange capacity and high water uptake. The protonic conductivity of the membranes equilibrated with water lies in the range 1.0-8.6 S/m, at 25 degrees C, being of the same order of magnitude as that reported for perfluorinated acidic membranes. The values of the transport number of protons and sodium ions are close to the unit for very dilute electrolyte solutions, but they lie in the range 0.80-0.90 for moderate concentrations. The membranes exhibit rather high electroosmotic permeability. The similarity of the diffusion coefficients of protons and water in the membranes suggests that the Grottus mechanism governs the protonic conductive process in the acidic membranes equilibrated with water.

Sulfonated naphthalenic polyimides containing ether and ketone linkages as polymer electrolyte membranes

“…Sulfonated diamine monomer, 4,4-bis[3-sodium sulfonate-4-aminophenoxy]benzophenone (BSAPBP), was similarly synthesized. It should be noted that the starting dihalocompound, target product, reaction conditions and purification procedure for the preparation of BSAPBP were quite different from the reported work by Riande and co-workers [28], in which a dichloro compound was the starting material and the prepared sulfonated diamine was in the acid form.…”

“…A synthetic approach for preparing diamine monomers, based on the reaction of activated difluoro/dichloro compounds and 4-aminophenol, has been developed for the preparation of polyetherimides [27]. Recently, this synthetic strategy was also applied to the preparation of disulfonated diamine monomers, such as 3,3 ′ -disulfonic acid-bis[4-(3-aminophenoxy)phenyl]sulfone [16] and 4,4 ′ -bis(4-aminophenoxy)benzophenone-3,3 ′ -disulfonic acid [28].…”

Ion-Exchange Membranes Based on Polynorbornenes with Fluorinated Imide Side Chain Groups

“…In spite of the high water uptake of the P5FNDIHS membrane, the moles of water per anionic fixed group in the membrane, λ, are of the same order as that reported for Nafion [20] and copolyimide acid membranes [21,22]. However, it is surprising that the value of λ for the low IEC C5FNDIHS membrane is nearly four times that of the P5FNDIHS.…”

Ionic transport phenomenon across sol–gel derived organic–inorganic composite mono-valent cation selective membranes

“…The electro-osmosis arises from the motion of ions and thus associated water molecules in the pores of membranes under the action of an electric field. Electro-osmotic permeability (P e ) was expressed by [4]:…”

“…The ion-exchange membrane (IEM) is one of the most advanced separation membranes, which have been widely used in the solutions containing multi-ions: electrodialytic concentration of seawater or brackish water to produce sodium chloride and potable water, separation of inorganic ions from uncharged organics, alkali and transition metal ion recovery, as a separator for electrolysis such as chlor-alkali production, etc. [4][5][6][7][8][9][10][11]. For all these applications, IEMs should exhibit high ionic conductivity, but no electronic conductivity, and high counter-ion permselectivity.…”