DMC catalyst is an effective catalyst for the ring-opening polymerization of epoxy compounds and is one of the important research directions of polyether synthesis in recent years.
DMC catalyst is generally prepared by the reaction of water-soluble transition metal hydrido complexes with water-soluble metal halides under the action of organic ligands and polymer chelating agents. DMC catalyst has the advantages such as high activity, low unsaturation degree of synthetic polyether products and narrow distribution of relative molecular mass. However, the polymerization temperature is required to be above 100°C, and the higher the polymerization temperature is, the greater the influence on the quality of polyether products is.
The ring-opening polymerization of propylene epoxide catalyzed by DMC catalyst has a high conversion rate (up to 98.88%) even at low temperature (40-50°C), and DMC catalyst is an effective catalyst for the ring-opening polymerization of propylene epoxide. During the synthesis of the catalyst, the addition of chelating agents PL400 and PL1000 shortens the polymerization reaction time by 2.5-7 hours, and the addition of PL1000 is more beneficial to the improvement of the catalyst. The designed relative molecular mass increases from 3000 to 6000, and the polymerization time reduces by 3.7 hours.
In the case where the designed relative molecular mass is large, the polymerization reaction is faster and easier. The kinetic characteristics at the initial stage of the polymerization indicate that the ring-opening polymerization of propylene epoxide catalyzed by DMC has a first-order relationship to the monomer concentration.