Abstract: The production of phosphazene polymers represented by the general formula ##STR1## WHEREIN N IS AN INTEGER FROM 7 TO UPWARDS OF 50,000 WHEREIN ONE OR MORE KINDS OF OR or OR' groups is attached to the phosphorus atoms in a substantially linear chain of alternating P and N atoms, the groups when more than one group is present being randomly distributed along the PN backbone, is enhanced by employing a single solvent for both each of the reactants (polydihalophosphazene and either aryloxide and/or alkoxide) and for the product (phosphazene polymer). By this expedient, the formation of the desired product is achieved in a homogeneous system rather than in a heterogeneous system as in the prior art where different solvents were employed for each of the reactants and for the reaction products.

Abstract: The production of phosphazene polymers represented by the general formula ##STR1## WHEREIN R and R' are organic radicals hereinafter defined, and wherein n is an integer from 20 to upwards of 50,000 wherein one or more kinds of OR or OR' groups is attached to the phosphorus atoms in a substantially linear chain of alternating P and N atoms, the groups when more than one group is present being randomly distributed along the PN backbone, as described in copending United States Patent Application Ser. No. 824,004 filed Aug. 12, 1977, is enhanced by an improved procedure for the separation of the sodium chloride by-product from the derivatized phosphazene polymer. By treating the reaction mixture with carbon dioxide, in the presence of water and preferably with an additional alkali metal salt, agglomeration of the sodium chloride is accomplished, and a clean separation of the NaCl from the polyphosphazene ester is more readily achieved.