Preparation Of Water Absorbing Functional Polymer Microspheres And Its Application In Tertiary Oil Recovery

In this paper, a series of crosslinked polyacrylamide microspheres (PAMCMS), with the average particle size between 8~175μm were prepared by inverse suspension polymerization using acrylamide as main monomer, N,N′-methylenebisacrylamide (Bis-A) as crosslinker, span-80 as dispersion stabilizer, potassium persulfate (KPS) as initiator and cyclohexane or liquid wax as the continuous phase. The particle sizes of the microspheres were characterized by using optical microscopy and scanning electron microscopy (SEM). The influences of the stirring speed, amount of KPS and span-80, ratio of cyclohexane to water on the particle sizes of the PAMCMS were studied respectively. The result shows that the final particle sizes of PAMCMS decreases with the increasing of the stirring speed, the span-80 content and the ratio of cyclohexane to water. however, decreases with the decreasing of KPS content, with other conditions confirmed. The basic recipes were confirmed on the study. A series of PAMCMS with different crosslinking degree was prepared by changing the amount of crosslinker. The influences of the the crosslinker amount on the swelling properties of PAMCMS were gained by testing the volume change of the PAMCMS both in deionized water and in 1mol/LNaCl solution.Further more, a series of copolymer was prepared, by using some hydrophilic monomer (e.g. NaAAc, HEMA, HPMA) as the copolymerization monomer(second monomer). A typical copolymer is the P(AM-HEMA) microsphere. The IR spectra of the product show that the second monomer copolymerized with AM. The influences of the kinds and amount of the second monomer on the copolymer's swelling properties were got by testing the volume changes of the copolymer microspheres both in deionized water and in 1mol/LNaCl solution. A recipe that can prepare copolymer microspheres with different swelling properties was confirmed.With the above knowledge of preparing PAMCMS confirmed, a kind of core-shell structure microspheres were prepared, in which PAM was the core, PSt or PAN was the shell. This kind of microspheres were prepared by adding the hydrophobic monomer(St or AN), the hydrophobic initiator (AIBN), and also the hydrophobic crosslinker into the recipe. In this process the differences of the solubility of AM and the hydrophilic monomer in the dispersion medium was utilized. The particle size and sizes distribution of the microspheres was characterized by using SEM.The PAMCMS and the P(AM-HEMA) microspheres were used as plugging agent in the simulated plugging experiment, the results show that these two kind of microspheres plugging well.