Poly(1,2-glycerol carbonate): A Fundamental Polymer Structure Synthesized from CO2 and Glycidyl Ethers

The functional, aliphatic poly(1,2-glycerol carbonate) as a fundamental, simple polymer structure based on glycerol and CO2 was prepared by combination of glycidyl ether monomers with carbon dioxide via two different approaches. The material was obtained by two-step procedures either via copolymerization of (i) ethoxy ethyl glycidyl ether (EEGE) or (ii) benzyl glycidyl ether (BGE) with CO2, followed by removal of the respective protecting groups via acidic cleavage for (i) and hydrogenation for (ii). The resulting protected polycarbonate structures and the targeted poly(1,2-glycerol carbonate) were investigated with H-1 NMR and C-13 NMR spectroscopy as well as 2D-NMR methods. Removal of both protecting groups was possible without significant backbone degradation; however, the hydrogenation route for (ii) turned out to be advantageous. All new poly(carbonate)s have been characterized with respect to their thermal behavior. Protected and deprotected poly(1,2-glycerol carbonate)s were obtained with molecular weights in the range of 5000-25 200 g/mol and a PDI from 1.24 to 2.33. The degradation kinetics of poly(1,2-glycerol carbonate) in DMF has also been studied, demonstrating rather rapid degradation within several days to oligomers and cyclic carbonates.