Membrane formation begins with Nafion® pellets in the hydrolyzed form. These are ion exchanged with tetrabutylammonium hydroxide (TBAOH) to create a melt-processable form of the ionomer. Powders are created from the Nafion® TBA+ pellets by mechanical milling at cryogenic temperature. Milled powder is then mechanically pressed to form transparent membranes of optical clarity comparable to commercial Nafion®. These are then converted back to hydrolyzed form for testing. Previous work has indicated that hot isostatic pressing (HIP) of Nafion® membranes with varying levels of hydration can produce dramatic changes in mechanical properties. For this reason, a selection of samples is further processed by HIP at pressures of 45,000psi and temperatures in the range of 100 – 200°C.
Composite membranes are created by adding ceramic to the milling step of the preparation. The effect of adding up to 20 wt% ceramic on the thermal and mechanical properties of the material will be discussed. The influence of ceramic content on hydration will also be determined. Additionally, an effort will be made to determine the distribution of the inorganic phase within the membranes.
 R.B. Moore, K.M. Cable, and T.L. Croley, Barriers to flow in semicrystalline ionomers. A procedure for preparing melt-processed perfluorosulfonate ionomer films and membranes, J. Membr. Sci., 75 (1992) 7-14