Fully crosslinked poly [cyclotriphosphazene-co-(4,4′-sulfonyldiphenol)] microspheres via precipitation polymerization and their superior thermal properties

Fully crosslinked, stable poly[(cyclotriphosphazene-co-(4,4'-sulfonyldiphenol)] (PZS) microspheres have been prepared via the polyconclensation between hexachlorocyclotriphosphazene and 4,4'-sulfonyldiphenol by precipitation polymerization. The diameter of the PZS micropheres ranged from 0.6 th 1.0 mu m with the specific surface area of the microspheres ranging from 11.7 to 10.1 m2.g(-1). The formation of the non-porus microspheres was obsvered to obey an oligomeric species absorbing mechanism. The fully crosslimked chemical structure of the PZS microspheres were determined by IR, CP/MAS NMR, XRD, and EDX. No glass-transition temperature was observed and the onset of the thermal-degradation temperature was 542 degrees C. Thermal stability of the PZS microspheres by the precipitation polycondensation was significantly improved as compared with crosslinked microspheres produced by addition polymerizations.