Simultaneous addition of bromine and acrylate to the double bonds of fatty acids in triglycerides was achieved. In the first part of the study, methyl oleate was bromoacrylated in the presence of acrylic acid and N-bromosuccinimide as a model compound for the application of the reaction to the triglycerides. Next, soybean oil and high oleic sunflower oil were bromoacrylated by using the same procedure. The products were characterized by GC, IR,H-1-NMR, C-13-NMR, and mass spectrometry. The bromoacrylation yields for soybean oil and sunflower oil were 75 and 55%, respectively. A rigid thermoset polymer was prepared from the radical copolymerization of bromoacrylated soybean oil with styrene. The bromoacrylated sunflower oil-styrene copolymer showed semirigid properties. The crosslinked network structure of the copolymers was examined by their swelling behavior in different solvents. Glass transition temperatures were also determined and soybean oil-based polymer and sunflower oil-based polymer showed a glass transition at 55-65 and 20-30degreesC, respectively. The storage moduli of the soybean-based and sunflower-based polymers at room temperature were approximately 1.0 X 10(10) and 1.1 X 10(8) Pa, respectively. Photopolymerization was also carried out by using 2,2-dimethoxy-2-phenyl-acetophenoneas initiator. The response of the cured polymers to the thermal energy produced by a small flame was also tested by the ignition respond index method according to ASTM D 3713-78 and was found to be 5 B at 2.00 mm. (C) 2003 Wiley Periodicals, Inc.