HIGH-PERFORMANCE SIZE EXCLUSION CHROMATOGRAPHY OF POLY(ORGANO)PHOSPHAZENES

The determination of the molecular weights of polyorganophosphazenes can only be achieved with great care. The nature of the substituents, the proportion of residual chlorine atoms after substitution, and also any traces of hydrolysis can considerably modify the behavior of these polymers in solution and thus lead to erroneous results. In our current research we have been developing a characterization method based on steric exclusion chromatography, coupled with a light scattering detector. We have used columns with styrene–divinylbenzene organic micropacking as the stationary phase and THF with added LiBr (0.1 mol/L) as the eluent. This method has enabled us to establish accurate correlations between molecular weight, hydrodynamic volume, and viscosimetric measurements for polyaryloxyphosphazenes of varying structures and origins. The method also provides results which agree very well with the variables for the preparation of polyphosphazenes, which is based on polycondensation of P‐trichloro‐N‐dichlorophosphoryl monophosphazene Cl3P = NP(O)Cl2. Finally this method allows us to show that, despite their mineral backbone, these polymers obey Benoit's universal calibration concept. Copyright © 1990 John Wiley & Sons, Inc.