Water-soluble hyperbranched multi-arm polyacrylamide polymer and preparation method thereof

The invention provides a water-soluble hyperbranched multi-arm polyacrylamide polymer and a preparation method thereof. The polymer is composed of a spherical parent nucleus, an arm A and an arm B, wherein one end of the arm A is connected with the spherical parent nucleus, and the other end is connected with the arm B. The viscosity-average molecular weight of the polymer is 3.5-10 million, the mass ratio of the spherical parent nucleus to the arm A to the arm B is 1:(200-350):(7-18), and the degree of hydrolysis of the polymer is 20-40%. The spherical parent nucleus is polycyclodextrin with rich hydroxy groups at terminal groups. The arm A is an acrylamide-sodium acrylate random copolymer chain segment. The arm B is a poly-zwitterion choline functional chain segment. The preparation process of the water-soluble hyperbranched multi-arm polyacrylamide polymer is mild in conditions and simple and easy to implement, is green and pollution-free due to water-phase free-radical polymerization, and can not do harm to the human body. The water-soluble hyperbranched multi-arm polyacrylamide polymer has obviously higher tackifying property, salt resistance and shear resistance than the conventional linear polyacrylamide polymer, and has application prospects in oilfields.