Biodegradable polymers, 9 - technologically relevant aspects of kinetics and mechanism of ring-opening polymerization of l,l-dilactide

Poly(L-lactide) is manufactured by a cascade process comprising the fermentation of glucose substrate, oligomerization of L-lactic acid, cyclization depolymerization to L,L-dilactide and ring-opening polymerization of the cyclic diester. The process development requires detailed knowledge of kinetics, thermodynamics and reaction mechanism in all process stages. This paper aims to show the influence of micro- and macrokinetic factors on the course of the ring-opening polymerization and the parameters of the formed polyester. Monomer conversion and molecular weight of the polyester are by chemically active process parameters. like kind and concentration of catalyst and initiator, respectively, reaction temperature or presence of cocatalysts as well as by the intensity of mixing of the polymerizing The highest polymerization rate is observed in presence of tin octoate, but this catalyst leads to a fast degradation of the formed polymer.