Effect of including a hydrophobic comonomer on the rheology of an acrylamide‐acrylic acid based copolymer

Abstract

Synthesis and design of polymer systems based on acrylamide for enhanced oil recovery (EOR) is essential for reservoirs with high salinity and high temperature conditions. The use of associative monomers or the modification of the polymers with hydrophobic functional groups represents a promising alternative that extends the use of chemical EOR. In this study, terpolymers based on acrylamide, acrylic acid and butyl methacrylate were synthesized and the rheological properties of aqueous solutions of the obtained polymers at different pH values, and salt concentrations were evaluated. The results show that at alkaline conditions the viscosity of aqueous solutions of a polymer synthesized with 68.6 wt% of acrylamide, 22.9 wt% of acrylic acid and 8.6 wt% of butyl methacrylate increases by a factor of more than 1,000 at a 3 wt% concentration. Also, all polymers with the hydrophobic modification showed higher viscosity in saline solutions compared to their acrylamide‐acrylic acid analogue.

Neat and Aqueous Polyelectrolytes under a Steady-Shear Flow

“…The elongation of polymer molecules under shear and the increase of the collision frequency between groups of different polymer chains promote shear thickening. In such a way, Takeda et al , showed that aqueous polyelectrolytes containing solely hydrophilic species like poly­([2-(methacryloyloxy) ethyl] trimethyl ammonium) for polycations (PC) and poly­(acrylamide- co -acrylic acid) ,,,− for polyanions (PA) exhibit dilatancy. In their experiments, , molecular weights were 70–80 and ∼150 kg/mol for PC and PA, respectively.…”

Tannic Acid-Modified Poly(acrylamide-co-acrylic acid): A Versatile Approach for Aqueous Viscosity Modulation

“…14 The thermal initiator ABCN was used at a molar concentration of 0.05%, and both the initiator and the monomers were dissolved in 30 mL of ethyl acetate for the reaction. 15 To design the reaction concentrations and relative amounts of each monomer, the reactivity ratios of acrylamide and acrylic acid in the organic solvent were considered, which are 0.46 and 0.28, respectively. 16 Since both reactivity ratios are less than 1, the cross-propagation reactions should be preferred to homo-propagation ones, avoiding block copolymers.…”

Synthesis and properties of elevated temperature hydrogels for enhanced oil recovery based on AM/AMPA/NVP copolymer and silica nanoparticles

“…Meanwhile, the monomers with hydrophobic groups could form association regions in high-temperature environments to improve the polymer's heat resistance of the polymer. 25,26 Compared to HPAM, hydrophobic-associated polyacrylamide (HMPAM) with N-phenyl ethyl-methyl acrylamide as the main monomer exhibits excellent thermal stability, with a viscosity retention rate of 87.56% at 95 C. 27 To further improve the heat and salt resistance of HPAM polymers, more research suggested introducing multiple functional monomers into HPAM, enhancing the polymer's performance synergistically. It was reported that the multi-component copolymer synthesized by copolymerization of various functional monomers such as AM, SSS, and propylene oxoethyl trimethylammonium chloride (DAC), the viscosity retention rate of the copolymer still reached 38.9% at 120 C. 17 In addition, the stability of crosslinkers also played a vital role in the heat and salt resistance of polymer hydrogels.…”

“…In addition, monomers containing rigid groups, such as vinyl glycoside (GnR), 19,20 allyl group polyoxymethylene ether (APEG), 21,22 and N‐vinylpyrrolidone (NVP) 23,24 could increase the steric hindrance effect of the polymer chain, limit the free rotation of the polymer main chain, prevent the molecular chain from curling, and produce the effect of heat resistance and salt resistance. Meanwhile, the monomers with hydrophobic groups could form association regions in high‐temperature environments to improve the polymer's heat resistance of the polymer 25,26 . Compared to HPAM, hydrophobic‐associated polyacrylamide (HMPAM) with N‐phenyl ethyl‐methyl acrylamide as the main monomer exhibits excellent thermal stability, with a viscosity retention rate of 87.56% at 95°C 27…”