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

TiCl(O-i-Pr)(3)/SiO2 and Ti(O-i-Pr)(4)/SiO2 were prepared by immobilizing titanium(]V) 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 than those produced with the homogeneous catalyst. (C) 2008 Elsevier B.V. All rights reserved.