Hydrophobic modification for nanoscale cross-linked polymer microspheres

The properties of nanoparticles, however, are not only dependent on their size and shape, but also are determined by surface modification. As a novel in-depth profile control agent, nanoscale water-soluble cross-linked polyacrylamide microsphere has better compatibility, sealing and oil property. To improve the salt tolerances and shearing resistance, hydrophobic monomer is introduced to inverse microemulsion polymerization, and hydrophobic modified cross-linked polymer nanometer microspheres were obtained. The microscopic morphology, size distribution and plugging effect of the cross-link polymer micro-spheres dispersed system were studied through scanning electron microscopy (SEM), environmental scanning electron microscope (ESEM), fluorescence spectrophotometer, particle size analyzer, microporous membrane filter and the sand-filled pipe. The experimental results show that, the hydrophobic associations come into being in aqueous solution above a certain concentration, and so the particle size distribution model of hydro-phobic-modified cross-linked polymer microspheres deviate from double logarithmic distribution model which matches to non-hydrophobic cross-linked polymer microspheres. Hydrophobic modification of cross-linked polymer microspheres have better salt resistance and are able to enter the deep of the sand-filled pipe to form plugging. The disperse system of hydrophobic modified cross-linked polymer microspheres has different matching permeability range from that of non-hydrophobic cross-linked polymer microspheres, and using matching the permeability of core, higher displacement efficiency would be obtained.