Polyphosphazene plasticized resins

Claim 1

A process for foaming a plasticized fire-retardant, low-smoking composition comprising (a) a phosphazene homopolymer or copolymer comprising repeating units of the formula ##STR5## where R and R 1 are the same or different and are halogen, amino, C 1 to C 10 dialkylamino, C 1 to C 10 alkylamino, C 6 to C 14 arylamino, C 6 to C 14 diarylamino, C 1 to C 18 linear or branched alkyl, C 2 to C 18 linear or branched alkenyl, C 1 to C 18 alkoxy, C 6 to C 14 aryl, C 6 to C 14 aryloxy, substituted C 1 to C 18 linear or branched alkyl, substituted C 2 to C 18 linear or branched alkenyl, substituted C 1 to C 18 alkoxy, substituted C 6 to C 14 aryl, or substituted C 6 to C 14 aryloxy, the substituents selected from the group consisting of chlorine, bromine, nitro, cyano, alkoxy, aryloxy, alkenyl, amino, C 1 to C 10 alkylamino, C 1 to C 10 dialkylamino, C 6 to C 14 arylamino, C 6 to C 14 diarylamino, or mixtures thereof; and (b) from about 0.1 to about 100 parts by weight per 100 parts of said phosphazene homopolymer or copolymer of a compatible cyclophosphazene of the formula (NPR.sub.2x-y.sup.R.sub.ly).sub.x where R and R 1 are the same as above, x is at least 3, and y ≦ 2x; ; which process comprises mixing the composition with a chemical blowing agent and heating the mixture to a temperature sufficient to decompose said blowing agent.