Poly(monophosphazophosphazenes): New Polymers with N:PR3 Side Groups

Abstract

Phosphazene high polymers with N=PR 3 (phosphazo) side groups were prepared with trifluoroethoxy, phenoxy, anilino, and propylamino side groups. Small-molecule cyclic counterparts were also synthesized as model systems for the macromolecular inactions. These compounds were prepared using both (trichlorophosphazo)pentachlorocyclotriphosphazene (N 3 P 3 Cl 5 NPCl 3 ) and (trichlorophosphazo)pentafluorocyclotriphosphazene (N 3 P 3 F 5 NPCl 3 ) as the starting materials. Specifically, the synthesis of monophosphazophosphazene polymers through the thermal ring-opening polymerization of N 3 P 3 Cl 5 NPCl 3 at 150-180°C or of N 3 P 3 F 5 NPCl 3 at 200-210°C is reported. Differences in the reactivity of the phosphazochloro- and the phosphazofluorophosphazenes to halogen replacement reactions were found at both the cyclic trimeric and high polymeric levels. In general, replacement of the chlorine atoms by organic groups was achieved with greater ease than the replacement of fluorine atoms. For the reagents studied, the replacement of halogen atoms by sodium trifluoroethoxide was more facile than with the other nucleophiles. A comparison is made between the properties of monophosphazophosphazenes, classical phosphazenes, and 1,1-diphosphazophosphazenes