Testing of Sulfonation Degree of SPEEK and its Effect on Properties of Proton Exchange Membrane

Sulfonated polyether ether ketone (SPEEK) with various degree of sulfonation (DS) was prepared by commercial Victrex PEEK and concentrated sulphuric acid. Nuclear magnetic resonance (NMR) was used to measure the DS of SPEEK, then the influence of the DS to SPEEK performance was studied. Results showed that when the DS was above 80%, SPEEK would be excessive swelling, while the DS was between 48%-65%, SPEEK has good proton conductivity and methanol resistance properties and water absorption.