Preparation of new proton exchange membranes using sulfonated poly(ether sulfone) modified by octylamine (SPESOS)

Abstract

Sulfonated poly(arylene ether sulfone) (SPES) has received considerable attention in membrane preparation for proton exchange membrane fuel cell (PEMFC). But such membranes are brittle and difficult to handle in operation. We investigated new membranes using SPES grafted with various degrees of octylamine. Five new materials made from sulfonated polyethersulfone sulfonamide (SPESOS) were synthetized with different grades of grafting. They were made from SPES, with initially an ionic exchange capacity (IEC) of 2.4 meq g −1 (1.3 H + per monomer unit). Pristine SPES with that IEC is water swelling and becomes soluble at 80 • C, its proton conductivity is in the range of 0.1 S cm −1 at room temperature in aqueous H 2 SO 4 1 M, similar to that of Nafion ®. After grafting with various amounts of octylamine, the material is water insoluble; membranes are less brittle and show sufficient ionic conductivity. Proton transport numbers were measured close to 1.

Synthesis and characterization of new membranes deriving from sulfonated polyethersulfone for PEMFC applications

“…Grafting and/or crosslinking are mandatory for improving mechanical properties and suppressing solubility in hot water. Previous results have been reported by us using octylamine as a grafting reactant and/or PES-NH2 as a cross-linking agent [16]. We report here the use of para isobutyl-phenol as a grafting reagent and 4,7,10-trioxa tridecane-1,13-diamine as a cross-linking reagent.…”

“…An elementary Paxitech ® fuel cell was used to test the electrode membrane assembly performances [16,21]. The measurements were performed with a Voltalab ® PGZ301 potentiostat galvanostat, available from Dynamic EIS Voltammetry.…”

“…Hence, sulfonated polyethersulfone (S-PES) has shown many advantages to elaborate solid electrolyte for PEMFC [14,15], for example, good thermal stability, easy electrophilic substitution. In a former work [16,17], we studied the effect of octylamine grafting on the S-PES backbone (S-PES Octylsulfonamide: S-PESOS) and cross-linking with hexane diamine and amino polyethersulfone (HEXCl, ClNH2 membrane). It was found that the mechanical properties of the obtained membranes are improved as compared with unmodified S-PES.…”

Performance evaluation of sodium alginate–Pebax polyion complex membranes for application in direct methanol fuel cells

“…Consequently, there is an urgent necessity to develop energy efficient machinery that is ecologically friendly. Under these circumstances, fuel cells (FCs) are rapidly emerging as green alternatives to produce power in a pollution‐free and noiseless mode . FCs work on the principle of electrochemical reaction, wherein chemical energy is converted into electrical energy .…”

Ion exchange membranes based upon crosslinked sulfonated polyethersulfone for electrochemical applications

“…As presented by Kreuer [4], SPES containing 1 sulfonic acid pmu becomes water soluble at 80 1C, a behavior common to any sulfonated polyarylene. To overcome this problem, we proposed in a previous study [21] to substitute part of the sulfonic groups by aliphatic (n-octyl) sulfonamide groups (SPESOS). This operation led to an increased softness of the membrane as well as a sufficient ionic conductivity.…”