Composition,Structure And Properties Of Acrylamide-Zr Crosslinked Polymer Microspheres

Acrylamide polymer microspheres have become a promising flood control agent due to their excellent flood control properties.In order to adapt to reservoirs with complex formation conditions,it is necessary to improve the temperature resistance,swelling performance and viscosity increasing performance of microspheres,and the composition and structure of microspheres directly affect various properties of microspheres.Therefore,it is necessary to establish the relationship between the composition,structure and properties of acrylamide polymer microspheres.To this end,this thesis adopts the inverse emulsion polymerization method,using acrylamide(AM)as the main monomer,and introduce two functional monomers,2-acrylamido-2-methylpropanesulfonic acid(AMPS)and N-vinylpyrrolidone(NVP),the metal cross-linking agent zirconium acetate and the organic cross-linking agent N,N’-methylenebisacrylamide(MBA)were simultaneously introduced to prepare acrylamide-Zr polymer microspheres with different compositions and microstructures.Morphology,swelling properties,tackifying properties of microspheres,changes in microstructure and infrared absorption peaks during secondary cross-linking were studied by optical microscope,laser particle size analyzer,scanning electron microscope(SEM),HAAKE rheometer,fourier transform infrared spectroscopy(FT-IR),nuclear magnetic resonance(NMR)and elemental analysis.The results showed that the swelling and tackifying properties of the microspheres could be improved by changing the dosage of MBA and zirconium acetate.The microspheres with the best swelling and tackifying effect is P(AM-3.0Zr-0.05MBA)microspheres with AM monomer,3.0% zirconium acetate and 0.05% MBA content,and the initial particle size is 100 ～ 200 nm,the viscosity is as high as 124 m Pa·s at 90 ℃ for90 days,and the viscosity remains about 25 m Pa·s at 120 ℃ for 30 days,and the average particle size after swelling is about 2000 nm.During the swelling process of the microspheres,the amide group is hydrolyzed to generate-COO-,and the hydrolyzed zirconium acetate undergoes a coordination reaction with the carboxylate(R-COO-),resulting in secondary cross-linking,forming a "three-dimensional network structure with coexistence of balls and nets",so that the microsphere system maintains a high viscosity.The introduction of AMPS and NVP can improve the temperature resistance of the microspheres.The higher the temperature,the faster the viscosity increase and swelling rate of the microsphere system.The higher the content of zirconium acetate,the slower the viscosity of the microsphere system.The higher the MBA content,the slower the swelling of the microspheres.