Ring-opening polymerization sulfur heterocyclics

As discussed in Chapter 3, some other inorganic polymers also contain phosphorus atoms.47 They are derived from the basic phosphazene structure described in Chapter 3, and are obtained by the ring-opening polymerization of heterocyclic compounds in which one of the disubstituted phosphorus atoms is replaced by another moiety. Specifically, introduction of a carbon atom can yield poly(carbophosphazenes), with the repeat unit shown in 6.49. Alternatively, replacement with a sulfur atom can yield a poly(thiophosphazene) (6.50). Relatively little is known about these polymers at the present time 47... 

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