Poly(L-lactide) Epimerization and Chain Scission in the Presence of Organic Bases

Organocatalysis for polymer chemistry has become a subject of significant interest in the last two decades. In this contribution, we have studied evolution microstructure poly(L-lactide) solution toluene at 105 °C presence various organocatalysts. Weak bases such as triethylamine and DMAP (4-dimethylaminopyridine) lead to low extent epimerization chain scission reaction. The DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) amidine induces turn important extents both (up 37% D-stereoisomer formation) scission. This been tentatively attributed nucleophilic mechanism. Cinchona alkaloids only modest amount epimerization. Phosphazene are rather active, especially high catalytic loadings (>1 mol %). observed case is proposed occur via base-catalyzed hydrolysis Finally, it shown that combining an organic base with acid can synergistic effect regarding notably