Effects of Monomer Feed Amounts on Solution Properties and Solution Morphologies for a Comb-like Ter-polymer

ABSTRACT

An acrylamide(AM)-based ter-polymer (PAAB) containing sodium 2-acrylamido-2-methylpropane sulphonate (NaAMPS) and p-vinylbenzyl-terminated octylphenoxy poly(ethylene oxide) (VBE, polymerization degree: 24) was synthesized by an aqueous free-radical copolymerization. In order to obtain a PAAB polymer with both good thickening properties and surface and interfacial properties in brine solutions for enhanced oil recovery (EOR), the influences of the NaAMPS and VBE feed amounts on the intrinsic and apparent viscosities and the surface and interfacial tensions of the PAAB polymer in aqueous solutions were investigated. The optimum NaAMPS feed amount was 9 mol%; an excessive feed amount interfered with the aggregations of the PAAB macro-molecules in aqueous solutions and on the surfaces of aqueous solutions and the interfaces between aqueous solutions and kerosene. In addition, for this NaAMPS feed concentration, the PAAB polymer showed the highest apparent viscosities and the lowest surface and interfacial tensions in 5 g L⁻¹ NaCl for a VBE feed amount of 1.1 mol%. The mechanism giving rise to the solution properties for this polymer was examined. For this purpose, the effect of the polymer concentration on the supra-molecular structures of the PAAB polymer in water and in 5 g/L NaCl, were investigated by ultraviolet spectral analysis using pyrene as a probe. A transmission electron microscope (TEM) was also used to observe the morphologies of the associated structures in aqueous solutions to explore the correlation between the solution properties and solution structures for PAAB; expanded polymer chain bundles were formed at a polymer concentration of 0. 4 g L⁻¹, higher than the critical micelle concentration (0. 3 g L⁻¹).

KEYWORDS:

• Acrylamide
• comb-like ter-polymer
• interfacial tension
• oil-flooding
• transmission electron microscopy
• ultraviolet analysis

Acknowledgments

We acknowledge the financial support of National Natural Science Foundation of China (contract grant number: 51674045), Freedom Innovation Foundations of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (contract grant number: 2014–192), and Sichuan Support Fundation for Academic and Technological Leader (contract grant number: XDPY-1702).