Homopolymerization and Copolymerization Kinetics of Trimethylene Carbonate Bearing a Methoxyethoxy Side Group

The polymerization kinetics of 5-[2-{2-(2-methoxyethoxy) ethyoxy}-ethoxymethyl]-5-methyl-trimethylene carbonate (TMCM-MOE3OM) synthesized using the organocatalyst 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) were studied and compared to those with the commonly used catalyst/initiator for ring-opening polymerization of cyclic carbonates and esters, stannous 2-ethylhexanoate. Further, the utility of each of these catalysts in the copolymerization of TMCM-MOE3OM with trimethylene carbonate (TMC) and L-lactide (LLA) was examined. Regardless of conditions with either catalyst, homopolymerization of TMCM-MOE3OM yielded oligomers, having number average molecular weight less than 4000 Da. The resultant molecular weight was limited by ring-chain equilibrium as well as through monomer autopolymerization. Interestingly, auto-polymerization of TMC was also achieved with DBU as the catalyst. Copolymerization with TMC using stannous 2-ethylhexanoate as the catalyst yielded random copolymers, while diblock copolymers were formed by copolymerization with LLA. With DBU as the catalyst, copolymers with LLA could not be formed, while blocky copolymers were formed with TMC. These findings should be useful in the incorporation of this monomer in the design of polymer biomaterials. (C) 2015 Wiley Periodicals, Inc.