Preparation And Modification Of Proton Exchange Membranes Based On Sulfonated Poly(arylenethioethersulfone)s

The proton exchange membrane fuel cell(PEMFCs),as a clean and high-efficiency new energy source,has attracted wide attention.Moreover,the proton exchange membrane(PEM)is core component of PEMFC system and its property directly affects the performance of fuel cells.High cost and great loss of proton conductivity at low humidity are serious drawbacks of commercialized Nafion.The sulfonated polyaromatic ether polymer membrane material is characterized by excellent mechanical property,chemical stability and heat stability.In this paper,the poly(arylenethioethersulfone)s(SPTES)were synthesized depending on molecular structure design,aiming to improve its drawbacks.In light of high swelling rate and severe pollution caused by disposal when degree of sulfonation(DS)of SPTES polymer is high,SPTES was modified with sodium lignosulfonate and ZrP inorganic particles,in order to reduce cost of SPTES polymer proton exchange membrane and improve stability of membraneFirstly,the properties of SPTES polymer with different sulfonation degree were analyzed and tested.Membrane of SPTES was formed by flow casting.SPTES proton exchange membrane showed better performance than Nafion117.The SPTES-50(with a 50%-sulfonation)membrane has following properties: water absorption: 51%;IEC:1.25 mequiv/g;proton conductivity: 100 mS/cm.All these were better than that of Nafion117 membrane.Secondly,the composite membrane materials were prepared by adding natural raw materials lignin sulfonate(LS)as additive phase,and then the performance of the composite membrane was tested.It was found that with the increase of doping amount,the proton conductivity and water absorption of the composite membrane increased first and then decreased.When the doping amount was 10%wt,the proton conductivity of SPTES-MLS-10 composite membrane is 105mS/cm,meanwhile the Nafion117 membrane was 80mS/cm under the same condition.Thirdly,the composite proton exchange membrane with different zirconium phosphate(ZrP)content was prepared by in-situ composite method.Its properties were tested.It was found that the composite membrane had better thermal stability,water absorption,water retention,higher proton conductivity and lower methanol absorbency.When the dopant was 17.5%,the proton conductivity of SPTES/ZrP-17.5 was 130mS/cm,which was 1.46 times of that of the SPTES membrane under the same conditions.