Catalysis in polymerization of cyclic esters. Catalyst and initiator in one molecule. Polymerization of lactide

Poly(L-lactide) (PLA) was synthetized with initiator and catalyst in one molecule (CINICAT): 5-ethyl-2-hydroxy-5-hydroxymethyl-1,3,2-dioxaphosphorinane-2-oxide (GM). Polymerizations were conducted at the relatively high temperature (170–190 °C) because of the low basicity of LA. Nevertheless, the studied processes were found to be living/controlled, no side reactions were determined and only PLA with fragments of GM as the end-groups were detected. PLA with Mn up to ∼40·103 g/mol. Kinetic studies indicated second order dependence of the rate of polymerization on the initial concentration of the CINICAT. This result is suggesting activation of the monomer and propagation with two independent macromolecules.