In this research, a novel amphiphilic hydrophobically associative polymer nanocomposite (ADOS/OMMT) was prepared using acrylamide (AM), sodium 4-vinylbenzenesulfonate (SSS), N, N′-dimethyl octadeyl allyl ammonium bromide (DOAAB) and organo-modified montmorillonite (OMMT) through in situ polymerization. Both X-ray diffraction patterns and transmission electron microscopy images verified the dispersion morphology of OMMT in the copolymer matrix. Then, the effect of the introduction of OMMT layers on the copolymer properties was studied by comparing with pure copolymer AM/SSS/DOAAB (ADOS). The thermal degradation results demonstrated that the thermal stability of the ADOS/OMMT were better than pure copolymer ADOS. During the solution properties tests, ADOS/OMMT nanocomposite was superior to ADOS in viscosifying ability, temperature resistance, salt tolerance, shear resistance and viscoelasticity, which was because OMMT contributed to enhance the hydrophobic association structure formed between polymer molecules. Additionally, the ADOS/OMMT nanocomposite exhibited more excellent interfacial activity and crude oil emulsifiability in comparison to pure copolymer ADOS. These performances indicated ADOS/OMMT nanocomposite had good application prospects in tertiary recovery.

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Exfoliated organo-montmorillonite (O-Mt) layers were successfully encapsulated in a terpolymer microsphere (PAAA) of acrylamide (AM)/acrylic acid (AA)/2-acrylamido-2-methylpropanesulfonic acid (AMPS) via in situ inverse suspension polymerization, with the aid of the organic modification by cetyltrimethylammonium bromide (CTAB) and sodium lauryl sulfonate (SLS). The chemical structure and properties of the Mt were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), which showed that SLS molecules successfully intercalated Mt interlayers and enhanced the thermostability of Mt. The microsphere morphologies of the polymer and its nanocomposites were detected by scanning electron microscopy (SEM). The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that the exfoliated O-Mt dispersed in the polymer matrix. The introduction of well-dispersed O-Mt layers significantly enhanced the comprehensive performance of these microspheres, including thermostability and plugging properties. The Tmax of PAAA/1.5 wt.% O-Mt nanocomposite is increased by 46°C compared to the pure terpolymer. The plugging rate of PAAA/2.0 wt.% O-Mt reached up to 85.8%. Therefore, these selected nanocomposite microspheres can provide an effective plugging in the high-permeability layers.

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