Differences between initiator/terminator properties of phosphazene materials

Traditionally, most polyphosphazenes have been prepared by the thermal ring-opening and macromolecular substitution route. However, this approach allows only minimal control of the molecular weight and generates broad polydispersities. A new ambient temperature condensation synthesis method overcomes these drawbacks. The method involves the living cationic-induced polymerization of Me₃SiN double bond PCl₃ with trace amounts of PCl₅ and yields polymers with well defined molecular weights and narrow polydispersities. The method can also be used to synthesize both block and star-branched copolymers.