Composite membranes of sulfonated poly (phthalazinone ether ketone)s (SPPEK)s and Zirconium hydrogen phosphate (ZrP) or 12-phosphotungstic acid (PWA) were prepared by direct blending method. The physicochemical properties of these composite membranes were studied through Fourier transform infrared attenuated total reflection (FTIR-ATR) spectroscopy, field-emission scanning electron microscope (FSEM), X-ray diffraction (XRD) and thermogravimetry analysis (TGA). The SPPEK/PWA composite membranes showed better properties, whose highest proton conductivity could reach 0.17 S/cm at 80 degrees C under 100% relative humidity (R.H.). (c) 2006 Wiley Periodicals, Inc.