Antimicrobial composite membranes, formed by cellulose acetate loaded with AgNO3 particles, were produced by supercritical phase inversion. Different cellulose acetate concentrations were tested (15%, 20%, 30%(w/w)), whereas the active agent (i.e., silver nitrate) concentration was fixed at 0.1%(w/w) with respect to the quantity of polymer used. To determine the influence of the process parameters on membranes morphology, the pressure and temperature were varied from 150 to 250 bar and from 55 to 35 °C, respectively. In all cases, regularly porous membranes were produced with a uniform AgNO3 distribution in the membrane matrix. Silver release rate depended on membrane pore size, covering a time interval from 8 to 75 h.
Keywords: cellulose acetate; membranes; silver nitrate; supercritical CO2; supercritical phase inversion.