a polymer composed mainly of hexachlorocyclotriphosphazotriene
Freshly produced phosphonitrilic chloride is an amorphous substance that partially crystallizes upon extension. Density, 2.4 g/cm3 at 20°C. It exhibits considerable hyperelastic deformation; elastic modulus, 0.26–0.38 meganewtons per sq m, or 2.6–3.8 kilograms-force per sq cm (it is called inorganic rubber). It is incombustible and stable upon heating up to 300°C, and it hydrolyzes rapidly upon exposure to air, becoming brittle. Organic radicals (for example, C6H5, OC6H5, OC2H5, and NHR) are substituted for C1 atoms in phosphonitrilic chloride to impart resistance to hydrolysis. Such products, which have a molecular weight of 300,000–2,000,000, also have hyperelastic properties and low combustibility; they are soluble in organic solvents, are chemically inert, and undergo depolymerization at temperatures slightly higher than 200°C.
Phosphonitrilic chloride is produced by thermal or catalytic polymerization of the monomer. It is used in the manufacture of rubbers by substituting alkylamino, arylamino, alkoxy, or aryloxy groups for chlorine atoms; vulcanized rubbers made from this base material retain their elastic properties at temperatures down to –70°C.
V. V. KIREEV