ORGANOBISMUTH POLYMERS AS X-RAY CONTRAST MATERIALS - SYNTHESIS, CHARACTERIZATION AND PROPERTIES

Organobismuth monomers containing the Ph3Bi moiety were synthesized and polymerized to obtain homogeneous X-ray constrast polymers. Styryldiphenylbismuth (I), alpha-methylstyryldiphenylbismuth (II), tris(alpha-methylstyryl)bismuth (III) and (p-diphenylbismuthphenyl)vinyldimethylsilane (IV) were prepared via a Grignard reaction with BiPh2Cl. Monomers I and II are contaminated with significant amounts of Ph3Bi and divinyl compounds. Monomer I can be homo- and copolymerized radically and anionically, II can only be copolymerized, while IV did not polymerize at all. In anionic polymerization the carbanion also attacks the Ph-Bi bond of I and II. Glass transition temperatures were determined as a function of bismuth comonomer content for styrene and acrylate copolymers, and the thermal decomposition was also studied. Radiopacities in millimetres of aluminium per millimetre of polymer were found to be proportional to the molar bismuth content of the transparent copolymer specimens.