Synthesis and characterization of phosphazene di- and triblock copolymers via the controlled cationic, ambient temperature polymerization of phosphoranimines

Harry R. Allcock, Scott D. Reeves, James M. Nelson, Ian Manners

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Abstract

An advanced process for the synthesis of polyphosphazenes with controlled architectures has been investigated. By this method, a wide range of well-defined phosphazene di- and triblock copolymers with controlled molecular weights and narrow polydispersities have been synthesized (Mn up to 4.8 × 104 with polydispersities of 1.06-1.39). The diblock copolymers, {[N=PCl2]n[N=PR(R′)]m}, were synthesized by the cationic condensation polymerization of the phosphoranimines, PhCl2P=NSiMe3, Me(Et)ClP=NSiMe3, Me2ClP=NSiMe3, Ph2ClP=NSiMe3, and PhF2P=NSiMe3, at 35°C initiated from the 'living' end unit of poly(dichlorophosphazene), [Cl-(PCl2=N)n-PCl3+PCl6-] which was itself formed by the polymerization of Cl3P=NSiMe3 with small amounts of PCl5 initiator in CH2Cl2 at 25°C. Halogen replacement reactions through the use of NaOCH2CF3 and/or NaOCH2CH2OCH2CH2OCH3 on the diblock copolymers yielded fully organo-substituted macromolecules. In addition, the diblock copolymer {[N=PMe(Et)]n[N=PMe(Ph)]m} was formed by the block copolymerization of the two different organophosphoranimines. Triblock species were produced by the reaction of the 'living' difunctional initiator, -{CH2NH(CF3CH2O)2P-N-PCl3+ PCl6-}2, first with Cl3P=NSiMe3 and second with Me(Et)ClP=NSiMe3, followed by halogen replacement with NaOCH2CF3, to yield the triblock {[(Et)MeP=N]m[(CF3CH2O)2P= N]n-P(OCH2CF3)2NHCH2CH2NH- (CF3CH2O)2P-[N=P(OCH2CF3)2]n [N=PMe(Et)]m}. The evidence for the formation of the di- and triblock copolymers includes NMR, GPC, elemental analysis, and solubility data.

Original languageEnglish (US)
Pages (from-to)3999-4007
Number of pages9
JournalMacromolecules
Volume33
Issue number11
DOIs
StatePublished - May 30 2000

All Science Journal Classification (ASJC) codes

  • Materials Chemistry

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