Synthesis and properties of fluorinated hydrophobic association polyacrylamide as thickener for hydraulic fracturing fluid

Abstract

A novel, anionic fluorinated hydrophobic association polyacrylamide (FAPAM) was successfully synthesized from acrylamide (AM), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), acrylic acid (AA), and 1H,1H,2H,2H-heptadecafluorodecyl acrylate (HFA) by radical micellar polymerization using sodium dodecyl sulfonate and potassium persulfate as a surfactant and an initiator, respectively. This synthesis was confirmed by Fourier transform infrared and nuclear magnetic resonance spectroscopy techniques. The results showed that the optimal content of the added HFA monomer was 0.3–0.5% in weight to the as-prepared FAPAM, which possessed 300–400 mg L−1 of critical association concentration. The results also showed that the properties of FAPAM3-0.4 were best for the appropriate mass ratio of AM:AA:AMPS = 7:1:2. The apparent viscosity of FAPAM3-0.4 was 1350 mPa s in the aqueous solution, and the apparent viscosities of other samples were 161.5 and 148.3 mPa s when the Na+ and Ca2+ concentrations were 5000 and 2000 mg L−1, respectively. Moreover, the FAPAM3-0.4 showed excellent temperature resistance and shearing resistance, in which the apparent viscosity was approximately 478.8 mPa s at 100 °C for 120 min. The viscosity could be completely restored or even it could be slightly higher than its original value when the shearing rate decreased. The results indicated that the excellent performance of FAPAM3-0.4 may make it a potential candidate as thickener for hydraulic fracturing fluid in oil and gas fields.