Ceramic polyaniline composite porous membranes

Ceramic/polyaniline composite porous membranes are successfully made by dif fusing ammonium peroxydisulfate and aniline into inorganic membrane disks. The ceramic disks are fabricated by mixing CMC, water, kaolin and alumina f ollowed by the processes of drying, milling, sieving, pressing at 4000 poun ds, and firing. The pore size of the disk is approximately 1 mu m. When the concentration of the oxidant is 0.25 M and that of the monomer is 1 M, the incorporation of polyaniline into the ceramic disks levels off aft er about 40 hours. The maximum incorporation percentage is approximately 4. 86 wt% (0.18 g of polymer/3.7 g of disk). Characterizations of the ceramic disk and its composites include N-2-flow tests, solubility tests, BET, SEM, OM and acid diffusion studies. Nitrogen-flow tests indicate that the incor porated polyaniline is structurally unstable. However, after applying N-2 g as of 23 psig for about 40 min, no further degradation is observed in these composite membranes even under 40 psig of N-2 gas. BET shows that the surf ace area of the composite is greater than that of the ceramic disk. SEM rev eals that polyaniline is grown on the surface of the pores of the ceramic d isks. Time constants, corresponding to the time when the pH value reaches 3 6.8% of the initial value, are estimated from the results of acid diffusion studies. The magnitude of the time constant is in the following order: cer amic/Peani base > ceramic/Peani salt > ceramic/Pani base > ceramic/Pani sal t > plain ceramic.