Polymers with sulfur(VI)-nitrogen-phosphorus backbones: Synthesis, characterization, and properties of poly[(dialkylamino)thionylphosphazenes]

Aminolysis of the chlorinated poly(thionylphosphazene) [NSOCl(NPCl2)(2)](n) (2a) with several secondary amines NHR2 (diethylamine, piperidine, and pyr rolidine) yielded various hydrolytically stable poly[(amino)thionylphosphaz enes] [NSO(NR2){NP(NR2)(2)}(2)](n) 6 (a, NR2 = piperidine; b, NR2 = pyrroli dine) in which chlorine atoms at both the phosphorus center and sulfur were replaced. In addition, treatment of 2a with different equivalents of sever al secondary amines (diethylamine, piperidine, and pyrrolidine), followed b y addition of excess of n-butylamine, lead to a series of mixed-substituent poly[(amino)thionylphosphazenes] [NSO(NHR'){NP(NR2)(2)}(2)](n) 7 (NHR' = n -butylamine; a-c, NR2 = diethylamine; d, e, NR2 = piperidine; f, NR2 = pyrr olidine). The new moisture stable polymers were characterized by P-31, C-13 , and H-1 NMR spectroscopy and elemental analysis. The molecular weights of the polymers 6a, 6b and 7a-7f were in the range of (M) over bar (w) = 3.4 x 10(4) - 1.1 x 10(5) and (M) over bar (n) = 3.1 x 10(3) - 5.0 x 10(4) acco rding to GPC analysis in THF versus polystyrene standards. The thermal tran sition behavior was investigated by means of DSC. Glass transition temperat ures (T-g's) of the poly[(amino)thionylphosphazenes] 6a,6b and 7a-7f depend on the content of secondary amine versus primary amine and were in the ran ge of -13 to +27 degreesC. No melt transitions were detected.