Poly(aryloxyphosphazene) copolymers

Abstract

Poly(aryloxyphosphazene) copolymers and foams thereof having a significant portion of C.sub.1 - C.sub.4 alkoxyphenoxy groups are described. The copolymers consist of the units which occur in a nonregular fashion and are represented by the following general formulas: ##STR1## wherein R.sub.1 represents a C.sub.1 - C.sub.4 linear or branched alkyl radical in the ortho-, meta-, or para-position, and R.sub.2 represents hydrogen, a C.sub.1 - C.sub.10 linear or branched alkyl radical, or a C.sub.1 - C.sub.4 linear or branched alkoxy radical substituted on any sterically permissible position on the phenoxy group, with the proviso that when R.sub.2 is alkoxy, OR.sub.1 and R.sub.2 are different. The copolymers of this invention may contain small amounts of randomly distributed units in addition to the repeating units described above, these additional units containing reactive sites enabling the properties of the copolymers to be modified by crosslinking and/or curing. The copolymers are elastomers, have desirable tensile strengths and may be used to form flexible or semirigid foams. The copolymers are extremely fire retardant and produce low smoke loads, or essentially no smoke, when heated in an open flame.

Dependencies are inferred from the claim text.