SYNTHESIS AND STRUCTURES OF COOLIGO(LACTONE) MACROMONOMERS

Cooligo(lactone) macromonomers were prepared by cooligomerisation of ( S,S)-3,6-dimethyl-1,4-dioxane-2,5-dione (L-lactide), 1-oxacyclohexane- 2-one (delta-valerolactone) or 1-oxacycloheptane-2-one (epsilon-caprol actone), initiated by 2-hydroxy-3-methacryloyloxypropoxy)phenyl]-propa ne (BisGMA). Two different reaction ways were used for the synthesis: parallel reaction and step reaction of lactones and L-lactide. The mac romonomers were characterised by differential scanning calorimetry (DS C), size exclusion chromatography (SEC), H-1- and C-13-NMR spectroscop y and MALDI-TOF mass spectrometry. Cooligo(lactone) macromonomers prep ared by parallel and by step reaction show different molecular structu res resulting in different properties. Their glass transition temperat ures depend on the molar ratio of lactide and lactone as well as on th e degree of oligomerisation. Macromonomers with high amounts of L-lact ide units are partially crystalline.