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A novel amphiphilic polymer, APAM, for enhanced oil recovery (EOR), was synthesized by radical copolymerization of acrylamide, dodecyl polyoxyethylene acrylate (DPEA), and N-(1,1,3,3-tetramethyl butyl) acrylamide (TBA), using potassium persulfate-sodium bisulfite as initiator-activator. The aggregation morphological observation of APAM in aqueous and NaCl solutions was performed using scanning electron microscope. The ability of APAM to solubilize and emulsify n-heptane and crude oil was investigated by visual methods, microscopy, and particle size analyses. The results show that APAM forms supramolecular aggregates in aqueous and NaCl solutions and has strong emulsification ability. As a result, the emulsion consisting of APAM aqueous solution and n-heptane (or crude oil) is much more stable than that of HPAM (partially hydrolyzed polyacrylamide, widely used in EOR), indicating a important function of APAM to emulsify oil component. [ABSTRACT FROM AUTHOR]

Rheologic properties and the conformations of the mixed system of hydrophobically modified polyacrylamide and surfactants in distilled water with or without NaCl were investigated. The vacuum sublimation freezing-drying technique was employed to maintain the aggregation state of the mixed systems. Scan electron microscopy and transmission electron microscopy were used to investigate microstructure of the mixed systems formed, and obtain the system molecular configuration information. The results showed that the rheologic behavior of the mixed solution revealed by viscosity data and microconformation obtained depend on the salt existence and the hydrophobic group content of the polymer. The relationship between polymer microconformation and the macroscopic properties for the mixed systems was analyzed to explore the aggregating mechanism. [ABSTRACT FROM AUTHOR]

With the vacuum sublimation freezing-drying and rheological techniques, the salt/alkali/surfactant effects on the solution properties and the aggregate conformations of the polymers, synthesized hydrophobically modified poly (acrylamide) (HMPAM), were investigated. The experimental methods included viscosity measurements, the photomicroscopy, scan electron microscopy, and the freeze fracture transmission electron microscopy. The variety of conformations of the ultramolecular aggregates, the hydrophobical region, and the spatial network structures resulted from the hydrophobical interaction were studied. Combined results confirmed that HMPAM could form several of interesting three-dimensional network structures either in distilled water or NaCl solution. The results have revealed the mechanism of the salt/alkali/surfactant effects on the peculiar rheological properties of the solution. [ABSTRACT FROM AUTHOR]