High Inhibition of Bentonite Hydration by Use of a Homopolymer Containing Synergistic Bi‐Functional Groups

Abstract

Most current inhibitors control bentonite hydration at the partial phase by the single adsorption mode. To improve inhibition and action range, we synthesized a novel homopolymer inhibitor (PIM‐NH2) containing bi‐functional groups. Comprehensive experiments investigated the inhibition of PIM‐NH2 and other inhibitors. In immersion and linear expansion experiments, the hydration swelling of bentonite cake was incredibly restrained in 0.75 % PIM‐NH2 solution. The greater contact angle between 0.75 % PIM‐NH2 solution and bentonite cake indicated the retardation of water invasion. According to XRD analysis, the intercalation of 0.75 % PIM‐NH2 reduced the bentonite lattice spacing from 1.91 nm to 1.27 nm with water discharge. All results suggested PIM‐NH2 had an outstanding performance at the lower concentration, and its inhibition covered the whole hydration process. Mechanism investigation revealed two synergistic adsorptions (hydrogen bond and electrostatic attraction) of bi‐functional groups exerted simultaneously to improve each other. In FT‐IR spectra, the hydrogen bond was confirmed by the special frequency movement from 1550 cm−1 to 1641 cm−1. The electrostatic attraction decreased the ζ potential absolute value from 29.55–33.20 mV to around 4 mV. In ESEM analysis, the bentonite treated by 0.75 % PIM‐NH2 showed larger aggregates and rough surfaces, demonstrating dehydration properties.