Intramolecular trifunctional Lewis acid-base pair catalyst, cyclic topology pmmbl polymer and preparation method and application

The invention relates to the technical field of catalysts, in particular to intramolecular trifunctional Lewis acid-base pair catalysts, preparation methods and applications, ring topology PMMBL polymers, preparation methods and applications. The intramolecular trifunctional Lewis acid-base pair catalyst provided by the present invention has any one or several structures shown in formulas I to III. The catalyst provided by the present invention adopts the chain growth mechanism of "bimolecular synergy". Two Lewis acid sites of B and one Lewis base site of P of the catalyst simultaneously exist in the same molecular structure through covalent bonding and acidic The application of the weaker B-site Lewis acid is favorable for the ω-end of one polymer chain to attack the α-terminus of the other chain, so that the catalyst structure leaves and the two polymer chains connect end-to-end to form a ring to prepare a high initial heat Degradation temperature and narrow thermal degradation temperature window for ring topology PMMBL polymers.