Study On Synthesis, Properties And Structure Of Comb-like Acrylamide-based Copolymers

This paper synthesized A novel macromonomer p-vinyl benzyl po1yoxyethylene octylphenol ether (VBPOE), which molecular structure was identified by 1H NMR. The comb-like acrylamide copolymers(PAVA) were synthesized using acrylamide (AM), VBPOE and sodium-2-acrylamido-2-methylpropane sulphonate (NaAMPS) by micellar free radical copolymerization technique, and the copolymers were characterized with FT-IR and 1H NMR. The influences of all synthesis condition of PAVA on solution viscosifying properties were studied, then the fit reactional condition were gotten.When fraction of VBPOE is 2.0%, the apparent viscosity of 0.10 g/dL PAVA and 0.20 g/dL PAVA respectively in pure water is 231.2 mPa·s and 2464 mPa·s; 0.15 g/dL PAVA and 0.20 g/dL PAVA respectively in 5000 mg/L NaCl solution is 112.7 mPa·s and 456.9 mPa·s(45℃, 7.34 s-1), indicating that the copolymers exhibit good thickening and salt resistance property. The apparent viscosity of 0.20 g/dL PAVA in 5000 mg/L NaCl solution is up to 187.1 mPa·s for 30 days under 45℃, the rate of viscosity retention was 41.1%, the copolymers exhibiting good heat-resisting property and long period stability. The aqueous solution of PAVA copolymers exhibited shear-thickening behavior under shearing, the viscosity restoring measurement revealed that the aqueous solution of PAVA displays the good shear toleration and the good thixotropic behavior.Based on dynamic viscoelasticity experiment, the elastic modulus G′and the viscous modulus G″were rising with the copolymers concentration increasing. G′and G″of PAVA copolymers solution almost doesn't change by addition of NaCl, this is different from the hydrophobically associating copolymers of the line entirely. G′and G″was the same respectively under the low frequency, G' and G" of the solution increased significantly under high frequency, the complex viscosity of 0.20 g/dL PAVA in the 5000 mg/L,20000 mg/L,30000 mg/L NaCl solution were higher than its dynamic viscosity and displaying elastic behavior of the fluid-based form 0.05 rad/s to 50 rad/s, the elastic characteristics of 5000 mg/L NaCl solution was the most obvious.The micro-circumstance polarity of hydrophobic association area of PAVA copolymer was researched by the fluorescence probe. It shows that the non- polarity of PAVA aqueous solution become stronger with the increase of PAVA concentration. The value of I1/I3 of 0.05 g/dL and 0.20 g/dL PAVA were 1.63 and 1.35 in pure water, the value of I1/I3 of 0.05 g/dL and 0.20 g/dL PAVA were 1.53 and 1.31 in 5000 mg/L NaCl solution. The value of Ie/Im were increased with the copolymer concentration rising in in pure water and 5000 mg/L NaCl solution.Scanning electric microscope shows that hydrophobic association of free was existed in 0.1 g/dL PAVA solution, the number of hydrophobic association area increasing and the hydrophobic association of molecular chains becomes stronger and the size of the structure of the copolymers increasing with the copolymers concentration increased to 0.25 g/dL. The associative structure of the sheet together for mutual association system was formed in the 0.20 g/dL PAVA 5000 mg/L NaCl solution. The copolymers chains of PAVA macromolecules spreading and the chains of copolymers macromolecules as switchgrass-shape with the copolymers concentration increased to 0.25 g/dL. Resulting in the viscosity sharp increase in brine solution. The SEM reveals the relationship between the solution properties and aggregation of the molecular structure.