POLY[(ARYLOXY)CARBOPHOSPHAZENES] - SYNTHESIS, PROPERTIES, AND THERMAL TRANSITION BEHAVIOR

The cyclic carbophosphazene N3P2CCl5 undergoes thermal ring-opening polymerization at 120-degrees-C to yield the poly(chlorocarbophosphazene) [N3P2CCl5]n as a hydrolytically sensitive elastomer. This polymer was allowed to react with a variety of aryloxide nucleophiles to afford a range of hydrolytically stable poly[(aryloxy)carbophosphazenes] [N3P2C(OAr)5]n. These macromolecules were characterized by P-31, H-1, and C-13 NMR spectroscopy, IR spectroscopy, elemental analysis, differential scanning calorimetry, gel permeation chromatography and, in one case, light scattering. Analogous, small-molecule model reactions, in which the cyclocarbophosphazene N3P2CCl5 was allowed to react with the same aryloxide nucleophiles to yield the cyclic species N3P2C(OAr)5, are also described. The glass transition temperatures of the poly[(aryloxy)carbophosphazenes] are 16-42-degrees-C higher than those of their classical polyphosphazene analogues [NP(OAr)2]n. Possible reasons for the lower skeletal flexibility of poly(carbophosphazenes) compared to classical polyphosphazenes are discussed.