Synthesis and characterization of a β-cyclodextrin modified polyacrylamide and its rheological properties by hybriding with silica nanoparticles

Maleic anhydride modified beta-cyclodextrin (MAH-beta-CD) was copolymerized with acrylamide (AM) and 2-acry-lamido-2-methyl propane sulfonic acid (AMPS) to form a copolymer (denoted as AAMC) through redox free-radical polymerization. The copolymer was characterized by FT-IR, H-1 NMR and thermal gravimetric analysis. The silica nanoparticles suspension was mixed with AAMC solution, and their rheological properties were investigated under different experimental conditions. Results showed that AAMC/silica hybrid exhibited viscosity enhancement and better salt-resistance, temperature-tolerance and shear-resistance than AAMC. The AAMC/silica hybrid showed an impressive thermal stability at T = 85 degrees C after 15 days, and the viscosity reached about 2.5 times that of AAMC at 0.8 wt% nanoparticle loading. Dynamic rheology studies indicated that silica nanoparticles acted as physical crosslinkers among polymer molecules so as to enhance the elasticity of the AAMC/silica hybrid. The superior properties of AAMC/silica hybrid indicated that it has the potential to enhanced oil recovery.