Preparation of Polyrotaxane Cross-linking Agent with "Pulley" Effect and Its Potential Application in Swelling Grain Used as Profile Control and Water Plugging Agent

A kind of polyrotaxane with polymerizable double bonds was designed and prepared through three step reactions. Because the alpha-cyclodextrin can slide freely on the chain of polyvinyl alcohol, this polyrotaxane can be considered as a cross-linking agent with "pulley" effect. The structure of polyrotaxane was characterized by Fourier transform infrared spectrophotometer(FTIR), 2D nuclear magnetic resonance(NMR), X-ray diffraction(XRD), and so on. The swelling grains were prepared by copolymerization of acrylamide with novel polyrotaxane cross-linking agent and ordinary cross-linking agent N,N'-methylenebisacrylamide individually. The swelling ability and deformability of swelling grains were also investigated. After swelling for 51 h, for swelling grain prepared by novel polyrotaxane cross-linker, the water absorption is 8.32. The swelling grain is not broken and can restore the original state after receiving and with drawing 294.3 N external force. But for swelling grain prepared by ordinary cross-linker, the water absorption is 6.75. The swelling grain is broken after receiving 112.4 N external force. The swelling ability and deformability of swelling grain prepared by the polyrotaxane cross-linking agent are better than those of grain prepared by the ordinary chemical cross-linking agent.