Polyphosphazenes

Abstract

Most synthetic polymers are totally organic macromolecules derived from petroleum. One of the few exceptions is the broad class of polymers called polyphosphazenes, which have a backbone of alternating phosphorus and nitrogen atoms, and two organic or organometallic side groups linked to each phosphorus atom. The presence of the inorganic elements in the main chain generates synthesis and property advantages that generally cannot be obtained from classical organic macromolecules. Moreover, the most striking feature of polyphosphazene science is the enormous range of different side groups that can be linked to a phosphorus–nitrogen chain. Three main questions are driving the development of this field. First, what are the limits to the types of side groups that can be linked to the inorganic chain? Second, how do different side groups generate different polymer properties? Third, what are the actual or potential uses of the hundreds of different polyphosphazenes that have been synthesized?