Synthesis of norbornenyl telechelic polyphosphazenes and ring-opening metathesis polymerization reactions

Mono- and ditelechelic linear polyphosphazenes, functionalized with a norbornene end group, were synthesized through the termination of living poly(dichlorophosphazene) with norbornenyl phosphoranimines. These materials were employed as macromonomers for the synthesis of graft copolymers via the ring-opening metathesis polymerization (ROMP) of the terminal norbornenyl component. Norbornenyl monotelechelic polyphosphazenes with various molecular weights yielded un-cross-linked graft copolymers when subjected to ROMP. The ditelechelic polyphosphazenes yielded branched or cross-linked materials due to the multiple reactive sites. In addition, the 5-norbornene-2-methoxy phosphoranimine was polymerized via ROMP to yield materials that consisted of a polynorbornene backbone with phosphoranimine pendent side groups.