Drag reduction by acrylate copolymers under thermohydrolysis

A copolymer of acrylamide (AA), acrylonitrile (AN) and sodium 2-acrylamido-2-methylpropanesulfonate (AMPSNa) was synthesized by radical polymerization. The effect of drag reduction of turbulent water flow by the synthesized acrylate copolymer was studied by capillary turbulent viscometry at temperatures up to 140 °C. The temperature dependence of the characteristic value of drag reduction ( f DR ), the increment in the volumetric flow rate (∆ Q ) and the drag coefficient (λ) were determined. With the use of IR spectroscopy and elemental analysis data, the chemical composition of the acrylate copolymer was ascertained to be dependent on thermohydrolysis temperatures of up to 180 °C. The colloidal and molecular weight characteristics of the initial and hydrolyzed acrylate copolymer were measured by dynamic light scattering and capillary viscometry. The temperature dependencies of the copolymer characteristics were determined. The optimal composition of the acrylate copolymer in terms of its thermohydrolysis resistance within the operating temperature range of up to 180 °C was revealed. No new chemical compounds were found in the copolymer acrylamide – acrylonitrile – sodium 2-acrylamido-2-methylpropanesulfonate with the composition of [72]:[10]:[18] that was subjected to thermohydrolysis at temperatures up to 160 °C, with the exception of carboxyl groups in place of amides. Thermohydrolysis up to 200 °C causes partial degradation and changes in the acrylate copolymer. The intrinsic viscosity, molecular weight and average sizes of the solvated copolymer macromolecular coils were found to decrease with increasing hydrothermal treatment temperature.