Desenvolvimento de membranas de polietersulfona por inversão de fases.

Abstract

Polymeric membranes were produced from nanocomposites of polyethersulfone and clay in the proportion of 3 and 5%, by weight by phase inversion technique. For flat membranes it was used Brasgel PA-MMT, organically modified Brasgel PA-OMMT, Cloisite and Cloisite 20A clays were used and for hollow fiber membranes Brasgel PA-MMT and Cloisite Na clays were employed. The solvent’s used N, N- dimethylformamide (DMF) and for hollow fiber membranes Polyvinylpyrrolidone (PVP) was also used as an additive. From FRX, FTIR and XRD data of the clays, it was observed that the organic modification of Brasgel PA clay was effective and that Cloisite 20A is a commercially organophilic. XRD of the membranes, in general, showed exfoliated and/or partially exfoliated structure. However, the membranes with the Cloisite Na 5% and Cloisite 20A (3 and 5%) clays displayed intercalated structure and/or partially intercalated. MEV the membranes showed anisotropic structures, with the presence of macropores, and their density increased with clay addition. Contact angle results with distilled water, showed that clay addition decreased the angle, i.e. increased membrane wettability, which was most remarkable with MMT clay. A similar result was observed for the contact angle with oil. Flow curves of Distilled water permeability, showed that clay addition and clay identity increased the hydrophilicity and favoring a higher permeability, especially to the membrane with MMT. Oil emulsion permeability for the results, all membranes showed rejection values greater than 80%, which agrees with the standards required by the CONAMA. For hollow fiber membranes, both the introduction of clay as the PVP increased viscosity of the solution. By MEV, it was verified that both the type and amount of clay, as the GAP, influenced directly the morphology of these membranes.