Poly-dioxybiphenyl phosphazene random copolymers with pendant 3-hydroxy-propyl groups and polycaprolactone branches

The polyphosphazenes {[NP(O2C12H8)]0.75[NP(O–C6H4–CH2–CH2–CH2–OH)(O–C6H5)]0.25}n and {[NP(O2C12H8)]0.75[NP(O–C6H4–(CH2–CH2–CH2–OH))2]0.25}n, having pendant –OH groups, have been synthesized by the direct reaction of the intermediate {[NP(O2C12H8)]0.75[NP(Cl)2]0.25}n with the heterobifunctional reagent HO–C6H4–(CH2)3OH in the presence of Cs2CO3 which specifically activates the phenolic OH in the presence of the alkylic hydroxyl. The Sn(Oct)2 promoted ring-opening polymerization of ɛ-caprolactone at 110 °C on the terminal OH groups gave well defined polycaprolactone (P-CL) branched polyphosphazenes in good yield. The effects of the branching on the crystallization behaviour as well as the thermal stability of the new polymers have been studied.