The structure and application of amine‐terminated hyperbranched polymer shale inhibitor for water‐based drilling fluid

ABSTRACT Amine‐terminated hyperbranched polymer (HBP‐NH2), as an inhibitor in water‐based drilling fluid, is prepared by the polycondensation of diamine AB2 monomers. The primary amine and secondary amide structures are confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance hydrogen spectroscopy. Through time of flight mass spectrometry, the molecular weight of HBP‐NH2 is mainly distributed in the range of 200–1400. Also, the quasi‐spherical shape and the high temperature resistance (200 °C) performance of HBP‐NH2 are, respectively, certified through the environmental scanning electron microscope and the thermogravimetric analysis. In the inhibition performance test, the linear expansion rate of sodium bentonite in 3 wt % HBP‐NH2 aqueous solution is only 11.42%, which is lower than other inhibitors (KCl, FA‐367, and HPAM). Zeta potential analysis shows that HBP‐NH2 has a strong ability to inhibit the hydration and dispersion of sodium bentonite by protonated primary amine groups. Compared with the base slurry, the absolute value of zeta potential is reduced by 25.5 mV in the slurry containing 3 wt % HBP‐NH2 at 180 rpm. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45466.