THE USE OF XE-129 NMR EXCHANGE SPECTROSCOPY FOR PROBING THE MICROSTRUCTURE OF POROUS MATERIALS

The phenomenon of adsorption and desorption of xenon in an inorganic a luminium/zirconoxide fibre, in silica gel and in an organic polymer bl end is compared by Xe-129 2D-exchange NMR experiments. A fast chemical exchange between adsorbed, liquid and free xenon gas occurs in the ca se of the alumina/zirconia fibre. In contrast to this, for the polymer blend, exchange between different adsorption sites in the blend is ob served, but no exchange between adsorbed xenon and xenon ps. Hardly an y exchange of xenon between adsorbed and free ps occurs in silica gel even at larger time scales. We conclude that the inorganic fibre has a n open pore structure, in contrast to the examined copolymer.