Polymer sulfonation : a versatile route to prepare proton-conducting membrane material for advanced technologies

Abstract EN

Sulfonation of polymers is a viable method for making proton exchange membranes used in electrochemical devices.

Polyether–ether ketone was modified by using concentrated sulfuric acid (97.4 %) to produce ioncontaining polymers bearing HSO3 groups.

The sulfonated polymer was characterized for IEC, 1HNMR, DSC, and water uptake etc.

The degree of sulfonation of sulfonated PEEK was found to vary from 40 to 80 mol %.

The PEEK became amorphous after sulfonation (as evidenced from DSC and WXRD), which enhanced its solubility in organic solvents such as DMF.

The glass transition temperature, Tg increased from 151 oC for pure PEEK to 217 oC upon sulfonation.

The water uptake was also increased with sulfonation level, which provides formation of water-mediated pathways for protons involving SO3H groups.

The membranes from these polymers have a high potential for use in electrochemical devices such as polymer fuel cell and electrodialysis.