Effects of guest microparticles on the swelling behavior of polyacrylamide gels

Abstract

We report the effects of guest particles on the swelling properties of bulk polyacrylamide gels. The guest particles were the spheres of poly(N‐isopropylacrylamide) gel with submicrometer diameter, which were synthesized by an emulsion‐polymerized reaction in water. Polyacrylamide gels were prepared by a free radical polymerization reaction, immobilizing the gel microparticles with different concentrations at gelation. The macroscopic swelling ratio of this hybrid gel in a cylindrical shape was measured as functions of temperature and acetone concentration. The presence of guest particles was found to strongly affect the swelling behavior in the bulk gels when the concentration of incorporated particles exceeded a threshold. The experimental results indicated that the macroscopic volume in response to the temperature change should be determined by the guest particles above the threshold. On the other hand, the hybrid gel could not evidently shrink by adding acetone when the concentration of guest particles exceeded the threshold. To make clear the distribution of guest particles in the bulk networks, the fractured surfaces of dried gels were imaged by tapping mode atomic force microscopy. The guest particles were found to aggregate in the bulk homogeneous networks to form microdomains with densely connected structure, which became larger with increasing particle concentration. The roles of bulk networks as well as guest particles on the swelling behavior of hybrid gels were qualitatively discussed on the basis of the incorporated structure of guest particles, depending on the concentration of guest particles. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1696–1704, 2005

Compatibility Evaluation of In-Depth Profile Control Agents for Low-Permeability Fractured Reservoirs

“…Swelling particle (SP): Swelling particles are made of chemical reagents such as monomers, stabilizers, proppants and swelling agents, which are fabricated through crushing and screening after reaction [ 30 , 31 , 32 ]. Compared with CBG, SP not only have the advantage of a high plugging rate, but also have the characteristics of controllable gelling conditions, good temperature resistance and salt resistance [ 33 ]. In the practice of oilfield, SP can be used as the front slug of cross-linked bulk gel and swelling particle system for profile control, which can be used to treat fractured reservoirs with serious water channeling [ 34 , 35 ].…”

Crystal growth of PPS nanofibers during annealing studied by solid‐state 13C CPMAS NMR

“…More detail preparation process for the PPS and other polymer's nanofibers with the CLSD method had been described in the previous articles. 5,6 Polarized IR spectra were observed using JASCO FT-IR 4200 spectrometer to obtain the molecular orientation of the drawn PPS nanofibers at room temperature: measurement range of 4000-500 cm À1 , the spectral resolution of 4.0 cm À1 , and the number of scans of 60.…”

“…Recently, Suzuki et al have proposed the novel technique to make polymer nanofibers using a high-power carbon dioxide (CO 2 ) laser-based supersonic drawing method in the vacuum chamber, so called as the CLSD method: the drawing velocity is about 300-600 ms À1 . 5 The polymer nanofibers prepared by the CLSD method have characteristic properties with very long filaments and high molecular homogeneous orientation. In the previous article, 6 we showed that the crystallinity of the PPS nanofibers obtained by the CLSD method decreases with increase of the pressure in the chamber (p ch ).…”