Ring-opening polymerization of ethylene carbonate: comprehensive structural elucidation by 1D & 2D-NMR techniques, and selectivity analysis

Abstract

Ring-opening polymerization (ROP) of ethylene carbonate (EC) is associated with the emission of carbon dioxide during polymerization, which results in polymer chains containing ether linkages besides targeted carbonate linkages. In this study, ethylene carbonate is polymerized by ring-opening polymerization in the presence of sodium stannate trihydrate as a heterogeneous transesterification catalyst. Comprehensive structural analysis of the products is conducted by advanced one-dimensional (¹H & ¹³C) and two-dimensional nuclear magnetic resonance (NMR) techniques (COSY, HSQC and HMBC). MALDI-TOF MS analysis is also conducted to support the results obtained by the advanced NMR techniques. Conversion and average ratio of carbonate to ether linkages of the polymer chains are quantified by ¹H-NMR. Molar mass progression is evaluated by size exclusion chromatography. Finally, selectivity of polymerization conditions for molar mass and dispersity, conversion, and average ether content are evaluated by varying the temperature, catalyst content, monomer to initiator ratio and polymerization solvent.