Synthesis, characterization and catalytic activity of zinc complex for ring opening polymerization of lactide
In the present study, salicylaldimine zinc complex (Zn HMBED) was synthesized and its reactivity for the ring opening polymerization (ROP) of lactide was studied. The zinc complex was prepared by the reaction of zinc solution with one molar equivalent of salicylaldimine Schiff base ligand in methanol under a nitrogen atmosphere. Further, the complex was characterized by various spectroscopic methods, which showed tetrahedral geometry. X ray diffraction studies were used for the structure determination of the Schiff base. It was observed that the zinc complex is highly active towards the ROP of lactide. The rate of polymerization is heavily dependent on the initiator used. The zinc complex allows controlled ROP as revealed by the linear relationship between the percentage conversion and the number average molecular weight. Finally, a mechanism for the ROP of lactide is proposed by use of the above zinc complex. (c) 2016 Society of Chemical Industry