Butadiene / vinyl aromatic brominated, mixtures of such copolymers with a vinyl aromatic polymer, and polymeric foams formed from such mixtures.

A brominated copolymer thermally stable, the copolymer having polymerized a butadiene moiety and a residue of aromatic vinyl monomer, the copolymer having prior to bromination containing aromatic vinyl monomer 5 to 90 weight percent, based on the weight of the copolymer , a 1,2-isomer content of greater than 0 weight percent, based on the weight of residual butadiene, and a weight average molecular weight of at least 1,000 butadiene copolymer having brominated I containing nonaromatic double bonds , non-brominated, equal or less than 15 percent, based on the content of non-aromatic double bonds of the copolymer prior to bromination as determined by spectroscopy 1H-NMR, and a temperature of weight loss five percent, determined by thermogravimetric analysis (TGA) of at least 200 degrees Celsius.