When a drop of microspheres dispersion was observed under the light microscope, it was found that the microspheres aggregated together with water BIBR-1048 and then were squeezed into a polyhedron, as Fig. 4 illustrates. This interesting phenomenon demonstrates that the cross-linked polyacrylamide microspheres are quite soft particles.
Fig. 4. Deformation of microspheres during dehydration process.Figure optionsDownload full-size imageDownload as PowerPoint slide
3.3. Plugging properties
Nuclear-pore films are suitable for studying plugging mechanisms because they have well-proportioned cylindrical pores that can be treated as the cross section of a porous medium. Fig. 5 shows the filtration volume and time when the polymer microspheres dispersed system with a concentration of 100 mg/L after swelling at 40 °C for 10 days and an HPAM solution with the same concentration passed through the nuclear-pore film with 10 μm pores.
Fig. 5. Filtration volume vs. filtration time curve of the polymer microspheres dispersed system and the HPAM solution (a. HPAM; b. Cross-linked polyacrylamide microspheres).Figure optionsDownload full-size imageDownload as PowerPoint slide