Preparation and Properties of Branched Copolymer P(AM-AA-MACA-EAMA) Using Water in Water Emulsion Polymerization in Aqueous Salt Solution

Abstract

A functional monomer (EAMA) and a rigid monomer (MACA) were synthesized, respectively. Furthermore, a branched copolymer (BPAM) was prepared with acrylamide (AM), acrylic acid sodium (NaAA), EAMA, and MACA through water-in-water emulsion polymerization in ammonium sulfate aqueous solution. The BPAM dispersion was characterized with non-eyepiece digital inverted fluorescence microscope (NDIFM) and Melvin laser granulometer. The microstructure of BPAM was characterized with ¹H NMR and the molecular weight was measured with gel chromatograph. In the performance evaluation experiments, BPAM demonstrates superior properties on the aspect of viscosity and viscoelastic. Furthermore, BPAM exhibits better temperature resistance and shear resistance properties compared to the high-molecular-weight partially hydrolyzed polyacrylamide (HPAM). Moreover, for BPAM, the viscosity initially decreased then increased followed by a decrease in CaCl₂ solution. Due to the precipitation that occurred between Ca²⁺ and , the increase of CaCl₂ concentration was favorable for BPAM in a certain CaCl₂ concentration range. These features indicate that BPAM has a great potential application for enhanced oil recovery and hydraulic fracturing in shale gas, especially in high-temperature and high-mineralization oil fields.

GRAPHICAL ABSTRACT

Keywords:

• Branched copolymer
• salt resistance
• shear resistance
• temperature resistance
• water-in-water polymerization

ACKNOWLEDGMENTS

The authors acknowledge the experiment condition support from the Engineering Research Center of Oilfield Chemistry.