| In this paper,a cyclodextrin-modified hyperbranched monomer was prepared by combining cyclodextrin with hyperbranched polymer technology,and a betaine monomer was synthesized as a functional monomer.The two are copolymerized with acrylamide and acrylic acid to synthesize a polymer with high temperature resistance,salt resistance and shear resistance with cyclodextrin hyperbranched structure to improve the defects of the traditional polyacrylamide polymer.A sulfobetaine monomer DEPS was synthesized from dimethylaminoethyl methacrylate(DMAEMA)and 1,3-propylsulfonolactone(PS).The optimal synthesis conditions for DEPS were those:n(DMAEMA);n(PS)=1.1:1.0,the reaction temperature 40℃,and the reaction the time 20h.The optimal synthesis conditions for the quaternary copolymerization of AM-AA-MAH-β-CD-DEPS were optimized by single factor method:m(AM):m(AA):=2:1(85%of the total mass of the monomer),m(DEPS):m(MAH-β-CD-HPEA)=14:0.5(15%of total monomer mass),initiator dosage 0.3%,reaction temperature 55℃,monomer concentration 25%,reaction time 6h.The structure of the product was characterized by infrared spectroscopy and NMR spectrum.The β-cyclodextrin(β-CD)was modified by maleic anhydride(MAH)to synthesize modified P-cyclodextrin MAH-β-CD with terminal carboxyl structure and double bond structure.AB2 monomer was synthesized using methyl methacrylate(MMA)and diethanolamine(DEA)as raw materials by "one-step method".Then hydroxyl terminated hyperbranched polyurethane HPEA was synthesized using AB2 monomer as a branching unit,and the trimethylolpropane(TMP)as the core.The HPEA was further modified with MAH-β-CD to obtain a polymerizable cyclodextrin-modified hyperbranched polyurethane functional macromonomer MAH-β-CD-HPEA with a double bond and a hydrophilic group.The MAH-β-CD-HPEA was characterized by infrared spectrometer,and the results showed that the target product was successfully synthesized.The microscopic morphology of PADAH and the polymer PADA were compared.The results showed that the filamentary structure of the aggregates in PADAH solution was obviously thicker than that of PADA solution,indicating that the hyperbranched monomer polymer PADAH has a certain branching structure.The solutions properties of PADAH and PADA were studied.The results showed that when the concentration of PADAH was 2000 mg/L,the solution viscosity could reach 647 mPa s;at 90℃ The viscosity at PADAH was 237 mPa s and the viscosity retention was 37.5%;The viscosity at PADAH was 237 mPa s and the viscosity retention was 37.5%at 90℃ while the viscosity retention rate of PADA is 21.7%.Compared with PADA,polymer PADAH has better solution performance,which can meet the polymer requirements of oil displacement process.The rheological properties and dynamic viscoelasticity of the polymer PADAH and PADA solutions were studied,which proves that the former has better thickening ability and shear thinning.The results of dynamic viscoelasticity study show that the two polymers have good and good viscoelasticity,but the hyperbranched polymer PADAH has better viscoelastic properties and can be used in the reservoir to improve the microscopic oil displacement efficiency of polymer flooding.The effects of surfactant type and amount on the solution properties of polymer PADAH were investigated.The results showed that the anionic surfactant sodium dodecyl sulfate SDS and cyclodextrin modified hyperbranched polymer PADAH showed a good compounding effect.When the concentration of SDS is 0.1%and the concentration of PADAH is 1000 mg/L,the maximum apparent viscosity of SDS-PADAH poly/sheet composite system is 521 mPa s,and the lowest interfacial tension is 0.038 mN/m.The indoor flooding effect of the SDS-PADAH poly/table system with better performance was evaluated and compared with the PADAH polymer flooding. |
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