High performance size exclusion chromatography of poly(organo)phosphazenes

Abstract

SynopsisThe 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 C1,P = N-P(O)Cl,.Finally this method allows us to show that, despite their mineral backbone, these polymers obey Benoit's universal calibration concept.

Poly(dichlorophosphazene) As a Precursor for Biologically Active Polyphosphazenes: Synthesis, Characterization, and Stabilization

“…Stabilized PDCP−diglyme formulations were used for the direct HPLC analysis of PDCP. Characterization of chloro-substituted polyphosphazene using conventional chromatographic techniques has encountered a number of problems associated with its hydrolytic instability and high reactivity. ,− Because of the PDCP spontaneous cross-linking in the column and notorious distortions in its HPLC profiles, it is still most common to determine the molecular weight of this polymer by converting it to a hydrolytically stable poly(organophosphazene). , The extent to which these results can be used for the characterization of PDCP due to the possibility of scrambling the molecular weight parameters during the nucleophilic substitution reactions still remains a subject of discussion …”

Surface Modification of Poly(vinyl alcohol) by Peroxide-Initiated Grafting of a Poly(organophosphazene)

“…The columns used were a set of two similar Shodex 80M, with styrene−divinylbenzene organic micropacking as the stationary phase and THF with added LiBr (0.1 mol/L) as the eluent. A chromatix CMX 100 low-angle laser light scattering (LALLS) detector was inserted on line between the outlet of the columns and the inlet of the refractometer …”