Radiopaque organic-inorganic hybrids based on poly(D,L-lactide)

Hybrid organic-inorganic nanocomposites were prepared starting from alpha,omega-triethoxysilane-terminated poly(d,l-lactic acid) (PDLLA) to be used as potential radiopaque biocompatible coatings for medical devices. The synthesis of the organic phase precursors of given chain length was achieved via anionic polymerization of d,l-lactide using a bifunctional initiator and subsequent triethoxysilane functionalization of the end groups. PDLLA-based ceramers (ceramic polymers) were then synthesized by the sol-gel process at room temperature (rt) in the presence of different amounts of tetraethoxysilane. The rt-synthesized hybrids were then cured (at 80 or 130 degrees C), and their thermal and viscoelastic properties were investigated. All obtained hybrids were optically transparent, due to the nanometric dimension of the silica particles, and yielded clearly contrasted radiographic images.