Physicochemical characteristics of polyethers prepared using double metal cyanide catalysts

Branched macromolecular polyethers (PEs) based on propylene and ethylene oxides are used as an active base for composites of demulsifiers of oil emulsions. In this work, features of the polymerization of propylene oxide in the presence of double metal cyanide catalysts are studied using the example of PE based on monoethylene glycol and glycerol by varying the molecular weight in the range of 6000–150000. Polymerization is performed in a laboratory reactor at 110–120°C and a catalyst concentration of 50 to 300 ppm. The viscosity, iodine value, and molecular weight characteristics of the PE samples are determined. It is shown that PEs with molecular weights of 6000–40000 have narrow molecular weight distributions (MWDs) and low concentrations of unsaturated impurities. A further increase in the molecular weight of PEs leads to the broadening of MWDs and a polydispersity value of 2.5–3.9, due to the formation of low-molecular weight unsaturated and bifunctional PEs. The results from this work can be employed to developing a process technology for PEs using double metal cyanide catalysts.