Properties of poly(phosphazene-siloxane) block copolymers synthesized via telechelic polyphosphazenes and polysiloxane phosphoranimines

Linear A-B, A-B-A, and B-A-B block copolymers containing polyphosphazenes a nd polysiloxanes were synthesized and characterized. Two methods were used in the synthesis of these novel block copolymers. The first utilized hydros ilylation chemistry to couple monotelechelic polyphosphazenes with commerci ally available dihydride-terminated poly(dimethylsiloxane) (PDMS). The seco nd involved the termination of living poly(dichlorophosphazene) chains with phosphoranimine-terminated PDMS. The semicrystalline, hydrophobic copolyme rs, [(CF3CH2O)(2)P=N](x)-[(Me)(2)Si-O](y), and the water-soluble copolymers , [(CH3OCH2CH2OCH2CH2O)(2)P=N](x)-[(Me)(2)Si-O](y), were prepared by the li nkage of either hydrophobic or hydrophilic organic groups to the polyphosph azene backbone. These materials, with a polyphosphazene content from 19 to 73 mol % (43-90 wt %) were obtained with controlled molecular weights that ranged from 5600 to 108 900 Da. The syntheses, characterization, and physic al properties of the linear polyphosphazene-polysiloxane block copolymers a re reported.