Flame-retarded high impact polystyrene composition

Claim 1

A flame retarded polystyrene composition comprising from about 50 to about 90 parts by weight polystyrene, from about 9 to about 22 parts by weight of a branched polymer having a hydroxyl number of from 2.8 to about 30 of the structural formula ##STR8## wherein each repeating unit set out within the brackets of the structural formula is attached in an ortho or para configuration to its adjacent phenyl and phenoxy moiety; and wherein E is an end group of the formula ##STR9## Y is a side chain of the same structure and configuration as said repeating unit; the substituents Br, E and Y on each phenyl ring are attached only to the ortho or para positions relative the hydroxyl group in the structural formula and the oxygen atom in the repeating unit; each t, p and q are independently the integer 0 or 1, provided that the sum of t plus q plus q equals 2, and provided that from about 10 to about 80 percent of the repeating units have the side chain and end unit --Y--E attached thereto; and m is an integer such that the total molecular weight of the polymer ranges from 2000 to 20,000, and from about 1 to about 10 parts by weight fire retarding enhancing agent comprising an oxide or chloride of antimony, arsenic, bismuth, tin, lead or germanium.