Synthesis and characterizations of novel, positively charged hybrid membranes from poly(2,6-dimethyl-1,4-phenylene oxide)

A series of PPO based organic–inorganic hybrid membranes with both strong and weak base groups were prepared though sol–gel process of 3-aminopropyl-trimethoxysilane (A1110) and polymer precursors PPO–Si(OCH3)3(+), which were obtained by reacting bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) with A1110 and trimethylamine (TMA). The chemical structure of the step reaction products was confirmed by FT-IR measurements. The final hybrid membranes were characterized by TGA, IEC, SEM, water flux, water uptake, rejection rate as well as streaming potential. Results showed that the prepared hybrid membranes possessed higher thermal stability than usual polymeric charged membranes, anion exchange capacity range (2.44–2.95 mmol/g dry membrane), low water flux (5.09–12.26 L/(m2 bar h)), positively streaming potential even at high pH value, and decreasing water uptake and rejection rate towards gelatin when pH value increases.