H. Kricheldorf, Dirk-Olaf Damrau
Aug 1, 1998
Citations
1
Influential Citations
21
Citations
Journal
Macromolecular Chemistry and Physics
Abstract
The usefulness of the zinc salts of five different amino acids or amino acid derivatives as polymerization catalyst of L-lactide was studied and compared. The five amino acid (derivatives) were: N-acetyl-glycine. N-tosylglycine. L-proline, L-pyroglutamic acid and N-acetyl-4-aminobenzoic acid. All polymerizations were conducted in bulk. Due to the low reactivity of all Zn catalysts a reaction temperature of 150 C was needed to obtain yields around 90%. While the basic Zn prolinate caused partial racemization, the neutral Zn salts yielded poly(L-lactides) with 97-100% optical purity. Regardless of catalyst and reaction conditions only moderate molecular weights were obtained.