CONCENTRATION AND FRACTIONATION OF POLYVINYL ALCOHOL-ANIONIC SURFACTANT STABILIZED LATEX DISPERSIONS BY MICROFILTRATION

Crossflow filtration of various latex dispersions stabilised by polyvi nyl alcohol and anionic surfactants and with added hydrophobically mod ified water soluble polymers was studied. New data on permeate Bur rat es and rejections of the latex and polymer components are presented. H olding other parameters constant it was found that the pseudo-gel conc entration was dependent on the latex particle sizes and the compositio n of the solution, and that microfiltration membranes could be used to either concentrate or fractionate the feed. For some dispersions the steady state permeate flux shows a maximum when plotted against log(fe ed concentration), indicative of a change in the dominant filtration m echanism as concentration is increased. At low water soluble polymer c oncentration aggregation of the latex occurs, slowing the rate of perm eate flux decline; at high concentrations polymer in solution deposits onto the membrane surface and causes rapid flux decline.