Characteristics of silica-supported tin(II) methoxide catalysts for ring-opening polymerization (ROP) of L-lactide

Supported Sn(OMe)(2) catalysts were prepared on pretreated silica with various tin contents. A series of bulk polymerizations of L-lactide were conducted with homogeneous methoxide catalyst and silica-supported tin alkoxide catalyst to compare with their characteristics of the polylactide (PLA) produced. The conversion of L-lactide with the silica-supported methoxide catalysts was higher than that with the homogeneous catalyst at each monomer/catalyst molar ratio. The highest catalytic conversion and propagation constant (k(p)) was achieved at 180 degrees C. The spent catalyst was successfully recovered up to 85% by simple filtration of the polymer product. The heterogeneous catalyst system is advantageous for recycling the catalyst and the production of highly purified, metal-free grade PLA. (C) 2014 Elsevier B.V. All rights reserved.