Radiopaque Copolymers of Styryldiphenylbismuth Vinylbenzylphosphonate and Methyl Methacrylate

Styryldiphenylbismuth (SDB) has been copolymerized with vinylbenzylphosphonate ester (VBP) and methyl methacrylate (MMA) producing highly radiopaque copolymers and terpolymers. The phosphoryl ester groups were also converted to phosphonic acids and the polymers were characterized. Thermal analysis of the co- and terpolymers yielded single glass transition temperatures in the range 60−100 °C. Poly(styryldiphenylbismuth vinylbenzylphosphonate ester) copolymer is thermally stable up to 255 °C and degrades at ca. 285 °C, producing bismuth crystallites within the partially degraded polymer matrix. Radiopacities of the polymers were compared to aluminum standards and were found to be proportional to the bismuth contents. It was found that ca. 16 mol % (or 31.6 wt %) of styryldiphenylbismuth in the terpolymer of SDB, VBP, and MMA has double the radiopacity of aluminum.