Abstract:

A novel monomer was designed and synthesized, in which the cyano groups were distributed on three benzene rings linked by meta ether linkages. Then using this monomer and 2,5-dichloro-3'-sulfobenzophenone as raw materials, a series of novel micro-block copolymer proton exchange membranes(middle length-sulfonated polyphenylene-co-poly aryl ether ketone 3CN(m-SPP-co-PAEK 3CN x), x represents the ion exchange capacity of the polymer) was prepared by nickel(0) catalyzed coupling copolymerization. The experimental results show that these membranes exhibit low water uptake and swelling ratio as well as methanol permeability under similar ion exchange capacity. As the ion exchange capacity is equal to 2.16 and the temperature is 80 ℃, the water uptake and swelling ratio of m-SPP-co-PAEK 3CN 2.16 are 29.7% and 28.2%, respectively, while the water uptake and swelling ratio of SPP-co-PAEK MO 2.33 are 80.2% and 37.2%, respectively. At 25 ℃, the methanol permeability of the two membranes is 2.38 and 7.20, respectively. The good dimensional stability of the as-synthesized membrane can be attributed to the introduction of the polar-CN groups into the skeleton. With these properties, the prepared membranes are promising proton exchange membrane materials in fuel cell applications.

Key words: sulfonated poly(p-phenylene-co-aryl ether ketone)s, proton exchange membranes, microblock, swelling ratio, methanol permeability