An anti-biodegradable hydrophobic sulfonate-based acrylamide copolymer containing 2,4-dichlorophenoxy for enhanced oil recovery

We report here a novel anti-biodegradable hydrophobic acrylamide copolymer that was prepared from acrylamide, acrylic acid, sodium 3-(allyloxy)-2-hydroxypropane-1-sulfonate and N-allyl-2-(2,4-dichlorophenoxy) acetamide using the 2,2'-azobis(2-methylpropionamide) dihydrochloride initiation system. Subsequently, the copolymer was characterized by FT-IR, 1H NMR, TG-DTG and water-solubility. And the biodegradability test indicated that the copolymer was not deemed to be readily biodegradable via a closed bottle test established by the Organization for Economic Co-operation and Development (OECD 301 D). Meanwhile the copolymer could significantly enhance the viscosity of the aqueous solution in comparison with partially hydrolyzed polyacrylamide. A viscosity retention of 51.9% indicated the result of a dramatic improvement of temperature tolerance. And then the excellent salt resistance, shear resistance, viscoelasticity, long-term stability of the copolymer could be obtained, which provides a good theoretical foundation for the application in enhanced oil recovery. In addition, this copolymer exerted stronger mobility control ability with a resistance factor of 22.1 and a residual resistance factor of 5.0, and superior ability for enhanced oil recovery of 12.9%. Hence, the copolymer has potential application for enhanced oil recovery in high-temperature and high-salinity reservoirs.

Novel high salt content polymer electrolytes based on high Tg polymers

Conductivities greater than or equal to 10⁻⁸ S cm⁻¹ at T_g are reported in polymer electrolytes based on lithium triflate salt and a series of polymers whose T_g is greater than 90°C. The highest conductivities were observed for poly(acrylonitrile) based systems with salt concentrations greater than 60 wt.%. The conductivity in all cases investigated increases with increasing salt concentration. ¹H-NMR T₂ relaxation measurements suggest that T_g decreases with increasing salt content and confirms that these materials are glassy at room temperature and hence that the conductivity is significantly decoupled from the structural relaxations. It appears that the nature of the polymer is important in determining the level of ionic conductivity, possibly due to differences in polymer coordinating ability or differences in T_g. Polymer-in-salt mixtures based on a tetra-alkyl ammonium imide molten salt and several high T_g polymers are also reported. The conductivities of these mixtures appear to be independent of the polymer type.

A novel water-soluble hydrophobically associating polyacrylamide based on oleic imidazoline and sulfonate for enhanced oil recovery

3-(2-(2-Heptadec-8-enyl-4,5-dihydro-imidazol-1-yl)ethylcarbamoyl)acrylic acid (NIMA), 3-(diallyl-amino)-2-hydroxypropyl sulfonate (NDS), acrylamide (AM) and acrylic acid (AA) were successfully utilized to prepare novel acrylamide-based copolymers (named AM/AA/NIMA and AM/AA/NDS/NIMA) which were functionalized by a combination of imidazoline derivative and/or sulfonate via redox free-radical polymerization. The two copolymers were characterized by infrared (IR) spectroscopy, 1H nuclear magnetic resonance (1H NMR), viscosimetry, pyrene fluorescence probe, thermogravimetry (TG) and differential thermogravimetry (DTG). As expected, the polymers exhibited excellent thickening property, shear stability (viscosity retention rate 5.02% and 7.65% at 1000 s-1) and salt-tolerance (10:000 mg L-1 NaCl: viscosity retention rate up to 17.1% and 10.2%) in comparison with similar concentration partially hydrolyzed polyacrylamide (HPAM). The temperature resistance of the AM/AA/NDS/NIMA solution was also remarkably improved and the viscosity retention rate reached 54.8% under 110 °C. According to the core flooding tests, oil recovery could be enhanced by up to 15.46% by 2000 mg L-1 of the AM/AA/NDS/NIMA brine solution at 80 °C.