Preparation and Properties Investigation on Sand-Polyacrylamide Composites with Engineered Interfaces for Water Shutoff Applications

Herein, we report a facile preparation and characterization of polyacrylamide (PAM)-2D nanofiller (commercial graphene (CG) and hexagonal boron nitride nanosheets (h-BN)) composite hydrogel coated sand for water shutoff application. To prepare the sample, 4 wt% of aqueous PAM solution that is mixed with organic cross-linkers of hydroquinone (HQ) and hexamethylenetetramine (HMT) in 1:1 weight ratio, aqueous potassium chloride (KCl) solution and a specific amount of CG or h-BN. A specific amount of the above solution is added to sand and well mixed and subsequently cured at 150 °C for 8 hours. The prepared sand-polymer composites were characterized by Fourier-transform infrared spectroscopy (FT-IR) for chemical composition, X-ray diffraction (XRD) for successful polymer coating onto the sand, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) for thermal stabilities. the success of the sand coating was evaluated based on the peak intensities depicted for the sand-PAM gels with respect to neat-sand and neat-PAM. The absence of some of the peaks and their corresponding decrease in the intensities indicates the successful coating of the PAM hydrogel matrix onto the sand surface. The thermal stability of the sand samples has reached as high as 190.7 °C. The prepared material has a high potential for water shutoff applications.