Polymers used in the polymer flooding technique for enhanced oil recovery (EOR) should improve rheological properties of water phase to improve sweep efficiency so that they are more widely applicable for use in oil fields. This study aimed to determine the molecular weight of a novel polymer, partially hydrolyzed polyacrylamide (HPAM), and to explore the effects of rheological properties of the polymer solution on its performance in EOR. The polymer was synthesized through vinyl polymerization using acrylic acid and acryl amide. To evaluate HPAM, several methods are used in this study. Field flow fractionation revealed that it had ultrahigh molecular weight (UHMW; 7.330×10 6 Da absolute weight-average molecular weight). Results of rheological measurement showed that UHMW HPAM could be applied even at a concentration of 1000 ppm to achieve desired properties. Furthermore, UHMW HPAM showed viscoelastic behavior within a wide range of temperatures and salinities. Polymer flooding with UHMW HPAM recovered 4% more oil because of its high viscosity and molecular weight.
PVP (poly(vinyl pyrrolidone)) is a common polymer that behaves as a surface-regulating agent that shapes metal nanocrystals in the polyol process. We have used different polymers containing tertiary amide groups, namely PVCL (poly(vinyl caprolactam)) and PDMAm (poly(N,N-dimethyl acrylamide)), for the synthesis of gold polyhedrons, including octahedrons, cuboctahedrons, cubes, and higher polygons, under the present polyol reaction conditions. The basicity and surface coordination power of the polymers are in the order of PVCL, PVP, and PDMAm. A correlation is observed between the coordination power of the polymers and the resulting gold nanocrystal size. Strong coordination and electron donation from the polymer functional groups to the gold surface restrict particle growth rates, which leads to small nanocrystals. The use of PVCL can yield gold polyhedral structures with small sizes, which cannot be achieved in the reactions with PVP. Simultaneous hydrolysis of the amide group in PDMAm leads to carboxylate functionality, which is very useful for generating chemical and bioconjugates through the formation of ester and amide bonds.
High-molecular-weight poly(biphenylene oxide)s (PBPO) were prepared from AB-type monomers, 4′(3′)hydroxy-4-nitro-2,6-bis(trifluoromethyl)biphenyl, through a meta-activated nitro displacement reaction. The displacement of nitro leaving group activated by the two trifluoromethyl groups at the meta-position produced high-molecular-weight polymers, which implies that nucleophilic aromatic substitution reaction of the nitro leaving group proceeded very effectively with two activating groups at the meta-position. The obtained polymers have weight-average molecular weight of 20 800−143 300 g/mol and molecular weight distribution of 1.68−2.85. While two homopolymers of 4′-or 3′-hydroxy-4-nitro-2,6-bis(trifluoromethyl)biphenyl, p-PBPO and m-PBPO, showed a semicrystalline morphology, copolymers of the two monomers were amorphous and dissolved in a wide range of organic solvents. The PBPOs possessed a high glass transition temperature (T g ) in the range of 169 to 208 °C depending on their structure and high thermal stability with 10% weight loss temperatures from 486 to 542 °C in nitrogen and from 465 to 516 °C in air. Moreover, PBPOs containing two trifluoromethyl groups showed low refractive indices in the range of 1.4979−1.5052 as well as low birefringence values of 0.0095−0.0148.
Poly(aryl ether amide) containing o-nitroanilide forms a physical gel in polar aprotic solvents by solvent-induced change of hydrogen bonding modes, in which hydrogen bonding acceptor solvent molecules break intramolecular hydrogen bonding of o-nitroanilide and induce intermolecular hydrogen bonding.
In this study, single‐walled carbon nanotubes (SWNTs) were modified with trifluoromethylated poly(phenylene oxide)s via surface‐initiated chain‐growth condensation polymerization (CGCP) to enhance the solubility of SWNTs in various organic solvents. The gradual increase in solubility of the SWNT with polymer growth was monitored by the color change of the reaction mixture and by UV/Vis/NIR absorption spectroscopy.
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