Polyphosphazene membranes: Part 1. Isopropanol dye separations

Research has been conducted at the Idaho National Engineering and Environme ntal Laboratory to determine the characteristics of phosphazene polymers wh en used as membranes for chemical separations. Phosphazene chemistry allows tailoring of the polymers' mechanical and chemical properties to suit part icular applications. Separations discussed in this paper are models for sev eral applications needed in the chemical industry. Ligands on the polymers tested have included modified sugars, various glycols, and substituted phen ols. In some cases all of the substituents on the polymer were the same ent ity. In other cases, up to three different ligands were attached in attempt to develop polymers with all of the needed properties. Physical properties of the different materials varied from film forming rubbers to sticky mate rials. Some of the polymers gave good fluxes, excellent separations, and la sted for weeks, while others started out with good properties but failed ra pidly. A description of the separation performance relative to the separati on of isopropanol from dye is given in this paper.