Synthesis And Properties Of Polyphosphazene With Pendant Perfluorobutylsulfonylimide Group

Polyphosphazenes are macromolecules with an inorganic backbone formed by alternating phosphorus and nitrogen atoms. For the varieties of the substitution, the properties of the polymers are different, so polyorganophosphazenes have many applications, such as flame retardant, special rubber and electric material. But so far little researches on polyorganophosphazenes used as strong acid polymer are reported. Due to the high acid strength of sulfonimide acids, the materials containing sulfonamide group have many potential applications, such as polymer electrolyte, catalysts for organic synthesis. It is significant to incorporate perfluoroalkylsulfonylimides into polymers. In this paper, we used poly(diphenoxyphosphazene) as support, prepared a new polyphosphazene with pendant perfluorobutylsulfonylimide. Poly(dichlorophosphazene) was obtained by the thermal ring-opening polymerization of hexachlorocyclotriphosphazene which was synthesized with NH4Cl and PCl5, and then it was substituted by sodium phenol to get ploy(diphenolphosphazene), poly(diphenolphosphazene) was chlorosulfonated with chlorosulfonic acid, and the product reacted with perfluosulfonamide to get a new containing nitrogen acid pendant polyphosphazene. The reaction conditions were studied in this work. The structure and properties of this polymer was characterized by IR spectra, ¹H NMR, ¹⁹F NMR, UV spectra, gel permeation chromatography (GPC), thermogravimetric analysis (TGA). The polyphosphazene with perfluorobutylsulfonylimide pendant was a hygroscopic and strong acid polymer, and could be dissolved in some polar organic solvents. It was easy to form membrane. The thermal analysis result showed that the polymer was stable till 180℃, its thermal stability was better than polystyrene sulfonic resin. It had good catalytic activity when it was used as catalyst for the reaction of acetic acid with butanol.