Microstructural Insights into Ethylene Glycol‐Mediated Polyether Polyols Using Double Metal Cyanide Catalyst

Abstract

AbstractPolyether polyols are well established category of polymers, which are synthesized via ring opening polymerization (ROP) industrially using Double Metal Cyanide (DMC) catalyst with glycols as initiators. Establishing the role of glycol in initiation and its involvement in the polymer chain during the ROP of propylene oxide (PO) via DMC catalysis is of utmost importance. In this work, the experimental method is established to understand the role of ethylene glycol (EG) and its participation during initiation and chain propagation. Furthermore, the microstructure analysis of synthesized polyether polyols reveals that ethylene glycol initiates from both sides and participated in random copolymerization besides its role as an initiator in the polymeric backbone during the ROP of PO. Also, in‐depth studies of the polymeric microstructural distribution are carried out using 1H‐1H COSY, 1H‐13C HMQC, and 1H‐13C HMBC with the aid of multi‐pulse 2D correlation techniques along with carbon‐13 NMR chemical shifts. In‐depth understanding of the microstructure of the polyether polyols is established with the aid of the obtained polymeric regio‐irregular structures. The reactivity ratios of PO are found to be 0.89 and 0.57 by modified Kelen–Tudos and Fineman–Ross method, respectively, indicating higher reactivity of PO monomer in comparison to EG.