RESUMO
Polybenzimidazole (PBI) in beaded form (250-500 microm) has been characterized in the dry state by scanning electron microscopy (SEM), BET, and nitrogen porosimetry. In the swollen state, it has been characterized by inverse steric exclusion chromatography (ISEC) in tetrahydrofuran, toluene, and water, by ESR of TEMPONE (2,2,6,6-tetramethyl-4-oxo-1-oxypiperidine), and pulse field gradient spin echo (PGSE) NMR spectroscopy, toluene, in tetrahydrofuran, ethanol and water. The dry-state results are in good agreement with the ISEC results obtained in tetrahydrofuran, toluene, and water with regard to the 40-80 nm macroporosity. The swelling-dependent surface area and pore volume detected by ISEC in toluene and water reveal the amphiphilic nature of PBI.
