Ring-opening polymerization of L-lactide initiated by (2-methacryloxy)ethyloxy-aluminum trialkoxides. 1. Kinetics

Kinetic aspects of the synthesis of (2-methacryloxy)ethyloxy functionalized poly(L-lactide) macromonomers using aluminum mono- and trialkoxides carryi ng this functionality are presented. The results show the living character of the ring-opening polymerization independently of the reaction temperatur e, but there are some deviations of the classical first order with respect to the monomer concentration, particularly at 60 degrees C and for low mono mer/aluminum catalyst ratios. The comparative study of aluminum trialkoxide s with respect to the corresponding monoalkoxides makes clear that the poly merization initiated by trialkoxides is at least five times faster than tha t initiated by the monoalkoxide. This behavior is explained by taking into consideration semiempirical calculations based on the PM-protocol, which gi ves an idea of the reactivity of mono- and trialkoxides with good agreement between theoretical and experimental results.