3D-Polystyrene-polymethyl methacrylate/divinyl benzene networks-Epoxy-Graphene nanocomposites dual-coated sand as high strength proppants for hydraulic fracture operations

The present work reports 3D-cross-linked polymer network-based coating onto frac sand prior to the epoxy coating to prepare dual-coated sand proppants with very high-stress resistance. The 3D-cross-linked poly(styrene-methyl methacrylate)/divinyl benzene) (PS-PMMA/DVB) coatings have been successfully prepared by the in-situ one-step bulk polymerization method with AIBN as an initiator at 70 °C. The 3D-polymer networks coated sand particles were then added with a mixture of epoxy resin and cure (4:1) along with commercial graphene (CG) and cured at 150 °C for 5 min. Interestingly, the roundness and sphericity of the sand particles have been retained even after the dual coating. The elasticity (E), hardness (H), and the fracture toughness (Kc) of the dual coating (PS-PMMA/DVB)-(Epoxy-CG) have been reached a maximum of 7.78 GPa, 0.34 GPa, and 3.22 MPa m1/2 respectively. The mechanically and thermally reinforced dual-coated sand particles with very high-stress resistance up to 12,000 psi will be successful proppants for hydraulic fracture operations.