SYNTHESIS, GLASS-TRANSITION BEHAVIOR, AND SOLUTION CHARACTERIZATION OF POLY[(ARYLOXY)THIONYLPHOSPHAZENES] WITH HALOGEN SUBSTITUENTS AT SULFUR

The cyclic thionylphosphazenes [(NSOX)(NPCl2)2] (1a, X = Cl; 1b, X = F) undergo thermal ring-opening polymerization to yield the hydrolytically sensitive, elastomeric poly(thionylphosphazenes) [(NSOX)(NPCl2)2]n (2a, X = Cl, 2b, X = F). The reaction of these polymers with several different sodium aryloxides Na[OAr] yielded the moisture-stable poly[(aryloxy)thionylphosphazenes] [(NSOX)(NP(OAr)2)2]n (3a-6a, X = Cl; 3b and 4b, X = F) in which the sulfur-halogen bonds are retained. These new polymers were structurally characterized by P-31, H-1, C-13, and (where appropriate) F-19 NMR spectroscopy, IR spectroscopy, and elemental analysis. Molecular weights of the aryloxy-substituted polymers 3a-6a, 3b, and 4b were estimated by gel permeation chromatography and in one case (4a) by light scattering. The glass transition behavior of the polymers was investigated by differential scanning calorimetry. Glass transition temperatures of the poly(thionylphosphazenes) were in the range 56 to +55-degrees-C. The solution behavior of [(NSOX)-(NP(OAr)2)2]n (4a, X = Cl, OAr = OC6H4Ph-p) was investigated by low-angle laser light scattering and dynamic light scattering which yielded an absolute value of M(w)BAR = 64 000 and an effective hydrodynamic radius, R(h,eff), of 5.9 nm in THF at 22-degrees-C.