Characteristics of heterogeneous titanium alkoxide catalysts for ring-opening polymerization of lactide to produce polylactide

Abstract

TiCl(O- i-Pr) 3/SiO 2 and Ti(O- i-Pr) 4/SiO 2 were prepared by immobilizing titanium(IV) chloride triisopropoxide (TiCl(O- i-Pr) 3) and titanium(IV) tetraisopropoxide (Ti(O- i-Pr) 4), respectively, over pretreated silica. A series of solution polymerizations of l-lactide were conducted with homogeneous alkoxide catalysts and silica-supported titanium alkoxide catalysts to compare their catalytic activity and the characteristics of the polylactide (PLA) produced. The conversion of l-lactide with the silica-supported alkoxide catalysts was higher than that with homogeneous catalysts even though the catalyst activity was low. In addition, the PLA produced using silica-supported alkoxide catalysts had a higher molecular weight and T m than those produced with the homogeneous catalyst.