a-Methylene-?-butyrolactone (MBL) is a natural substance found in tulips and can also be prepared chemically from the biomass-derived itaconic anhydride, thus attracting considerable attention as a renewable monomer for the synthesis of acrylic bioplastics through a vinyl addition mechanism. Owing to the high thermodynamic stability of its five membered ring, the ring-opening homopolymerization of MBL has remained a challenge. On the other hand, when MBL is copolymerized with e-caprolactone (e-CL), ring-opening copolymerization can occur. However, because MBL readily undergoes vinyl-addition polymerization, due to the presence of a high energy exocyclic double bond, ring-opening copolymerization is always accompanied by addition polymerization; thus, the homogeneous copolymer has not been obtained.Recently, we successfully synthesized MBL ring-opening copolymers and homopolymers using coordination polymerization catalysts. In copolymerization of MBL and e-CL, homogeneous copolymers without any vinyl-addition homopolymer were obtained by controlling reaction conditions. The MBL incorporation up to 40 mol% can be achieved. Chain-end analysis by MALDI-TOF MS and 1H NMR techniques shows that the copolymerization proceeds through a coordination ring-opening mechanism. Intriguingly, the ring-opening homopolymerization can also be achieved by such coordination catalysts under certain conditions.

Coordination ring-opening homo- and copolymerization of naturally renewable a-methylene-?-butyrolactone into polyesters

248th National Meeting (2014)

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