Styrene was copolymerized with 2,3-dibromopropyl acrylate, 2,4,6-tribromophenyl acrylate, or pentabromophenyl acrylate in either aqueous emulsion, dimethylformamide, or benzene solutions with a free radical initiator, and the thermal and flammability properties of the resulting polymers are described. The reactivity ratios of the monomers and the initial reaction rates for homopolymerization and copolymerization reactions in benzene were established. The monomer reactivity ratios were found to depend slightly on the reaction medium. The reaction rates for both homopolymerizations and copolymerizations increased in the order styrene < 2,3-dibromopropyl acrylate < 2,4,6-tribromophenyl acrylate < pentabromoacrylate. The thermal stability of the polymers, determined from TGA and DTG measurements, showed that poly(2,4,6-trtbromophenyl acrylate) and its styrene copolymers were the most stable and the copolymers of styrene with 2,3-dibromopropyl acrylate had the best flame-retardant properties as was demonstrated by limiting oxygen index measurements.