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

• Silica-supported catalysts were prepared by reacting Sn(OMe)2 over pretreated silica.
• The supported catalysts showed great activity and conversion for PLA production.
• The immobilization of Sn(OMe)2 did not affect the chemical nature of active sites.
• The spent catalyst was successfully recovered up to 85% by simple filtration.

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 (kp) was achieved at 180 °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.

Morphologies of the (a) fresh catalyst and (b) separated catalyst after the polymerization and EDS mapping images of catalyst: (c) one particle of (a) and (d) one particle of (b). Eun Ju Lee, Kang Moon Lee, Jinhee Jang, Jin Suk Chung, Youngkyu Do, Sung Cheol Yoon, Seung Young Park.Figure optionsDownload high-quality image (305 K)Download as PowerPoint slide