Polyacrylamide copolymer/aminated carbon nanotube‐based aqueous nanofluids for application in high temperature and salinity

ABSTRACT Polymer aqueous nanofluids have numerous industrial applications due to their synergic properties as a polymer and nanoparticle in the same fluid. The main goal of this work was to prepare stable aqueous nanofluids with improved viscosity in high temperature and salinity conditions. Aminated carbon nanotube (OCNT‐TEPA) presented a CN photoemission peak at 285.5 eV in X‐ray photoelectron spectroscopy spectra, which is evidence of a grafting reaction. Fourier transform infrared spectra presented absorption bands attributed to amide and amine bonds. Elemental analyses showed 1.9 and 3.2 mass % N content increases for OCNT‐TEPA and OCNT‐TEPA‐AM, respectively. Samples aged at 70 °C in brine confirmed that the addition of OCNT‐TEPA increased the viscosity of nanofluids to 30% at day 90 compared to acrylamide–acrylic acid copolymer fluids. Nanotubes presented only 35% of the aminated functions compared to carbon black (Lima et al., Carbon 2016, 109, 209) , and their effects in the enhancement of viscosity and thermal and colloidal stability were 2× greater. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46382.