In the industrial production of polyglycolide (PGA) perpared

via

ring-opening polymerization (ROP) of glycolide (GL)

the catalysts used play a significant role in controlling the polymerization reaction and the molecular weights of the resultant PGA products. In this study of ring-opening polymerization of glycolide using various metal compound catalysts and hydroxyl initiators

the effects of different metal centers (tin

aluminum

zinc and zirconium) and different ligand structures (alkoxy

carboxylate

acetylacetonate and halogen) on the ring-opening polymerization reaction of glycolide and the coloring issues of the resulting polymer were investigated. It was found that the metal used dominantly determined its catalytic activity and the color of the PGA products obtained

while the anionic ligands showed only limited influence. Among the catalyst systems studied

the tin metal center catalysts exhibited the highest catalytic activity

enabling rapid and complete conversion of the GL monomer even at very low concentration. Moreover

the PGA products obtained from the tin or zirconium metal center catalysts possessed the most desirable color attributes.