Synthesis of Telechelic Polyphosphazenes via the Ambient Temperature Living Cationic Polymerization of Amino Phosphoranimines

Abstract

A method for the synthesis of well-defined mono-, di-, and mixed-telechelic polyphosphazenes produced via a living cationic polymerization of phosphoranimines is described. Amino phosphoranimines R−NH(CF3CH2O)2PNSiMe3 (R = Ph−, p-BrPh−, p-H3CPh−, CH2CHCH2−, and CH2CHPh−) were synthesized via a reaction between a bromophosphoranimine and the appropriate organic amine. Ditelechelic polymers [R−NH]2−[Cl2PN] n were prepared by quenching living poly(dichlorophosphazene) chains, [Cl3PN(Cl2PN) n −PCl3]+[PCl6]- with small quantities of the amino phosphoranimines. Cationic initiators of the amino phosphoranimines were also generated using PCl5 and were used to polymerize Cl3PNSiMe3, to give monotelechelic poly(dichlorophosphazenes). In addition, a mixed telechelic system was produced by the termination of an allylamino monotelechelic poly(dichlorophosphazene) chain with a bromoanilino phosphoranimine. In all cases, displacement of the chlorine atoms with sodium trifluoroethoxide yielded hydrolytically stable telechelic polymers with controlled molecular weights and low polydispersities.

Expanding Options in Polyphosphazene Biomedical Research

“…4. Synthesis of poly(dichlorophosphazene) from linear chlorophosphazene monomers, followed by chlorine replacement at the macromolecular level [28][29][30][31][32][33][34][35][36]. 5.…”

Generation of structural diversity in polyphosphazenes

“…An alternative to the ring opening polymerization of 2 used in most reactions is the condensation polymerization of a chloro‐phosphoranimine, as shown in Fig. . In this process, a catalytic amount or PCl 5 or a related Lewis acid brings about the formation of linear poly(dichlorophosphazene).…”

“…Thus, monomer 7 , in the presence of a Lewis acid initiator, undergoes a cationic condensation polymerization at room temperature to give shorter poly(dichlorophosphazene) chains than the ring‐opening route, but allows the chain length to be controlled precisely by the ratio of monomer to initiator. The advantage of this approach is that the polymerization is ‘living’, and chain growth continues until all the monomer is consumed, leaving an active chain end that can be used for the formation of block copolymers or comb, star, or dendritic structures …”

“…A few examples are shown in Figs and . Block copolymer formation via the living cationic polymerization . Finally, various approaches have been developed to use the living cationic polymerization, and the active chain ends so formed, to assemble block copolymers and other structures . These include phosphazene–phosphazene blocks with each block bearing different side groups, and phosphazene–silicone or phosphazene–organic polymer blocks (Fig.…”

Synthesis and Tribological Behaviors of Epoxy/Phosphazene‐Microspheres Coatings under Dry Sliding Condition

“…Polyphosphazene as an organic–inorganic hybrid polymer is a class of novel macromolecules containing alternate phosphorus–nitrogen single and double bonds with two changing organic side groups to be prepared new specific functions materials. Because the phosphorus–nitrogen bonds are extremely flexible due to the low torsional energy and a large variety of side groups, polyphosphazenes can be made with a wide range of chemical and physical properties, like excellent heat resistance, cold‐resistant, water‐tolerant, solvent resistance, radicalization resistance, biology and flame retardant performances in many areas …”