Preparation and Properties of Novel Boric Acid Modified Poly(aryl ether sulfone) Membranes

In this article, boric acid-modified poly(aryl ether sulfone) (PES-B) membranes were prepared by solution blending, solution casting, evaporation, and programmed temperature curing method for the first time. The chemical modification of poly(aryl ether sulfone) was accomplished by the curing of poly(aryl ether sulfone) with pendent phenyl hydroxide (PES-OH) under the function of boric acid. The reaction mechanisms and the effects of boric acid content were thoroughly investigated. Processing conditions and structures of PES-B were determined by FT-IR spectra. It has been found that the B(OH) 3/PES composite membranes were completely cured after treatment at 300 degrees C for 4 h. When boric acid content was over 4.7%, PES-B membranes presented phase separation and full cross-linking structures. DSC measurements demonstrated that the addition of boric acid had influenced the glass transition temperature of PES-B, which provided the proof of the appearance of cross-linking network structure. TGA results confirmed that the thermal stability of the prepared PES-B composites was improved. Furthermore, the cross-linked composite membranes exhibited excellent mechanical property and solvent resistance. (C) 2014 Wiley Periodicals, Inc.