The Synthesis of Cationic Gelatin Derivative and its Effect on the Swelling of Sodium Bentonite

In this study, a cationic gelatin derivative (denoted as GCTA) was synthesized and its effect on the swelling of sodium bentonite (Na-BT) was investigated. The inhibitive properties of GCTA were evaluated through linear swelling test and hot-rolling recovery test. Results suggested that GCTA displayed better inhibitive ability than KCl and polyether amine (PEA). The underlying inhibitive mechanisms were also investigated by measuring interlayer spacing through X-ray diffraction, observing shale cuttings through scanning electron microscope and measuring the change of zeta potential of Na-BT dispersion. GCTA could strongly adsorb on the surface of clay particles and coat the particles. Meanwhile, the molecules entered the interlayer space, expelled water and decreased the interlayer spacing. This study can provide new insights into the design of environmentally friendly and highly effective clay inhibitors for water-based drilling fluids.