Simple cationic polyacrylamide: a drag reducer

A very simple cationic monomer and a cationic hydrophobically associating polyacrylamide were synthesized, and the polymer was to function as a drag reducer. The structures of monomer and polymer were characterized by IR and NMR, and the drag-reducing rate, below and above the critical association concentration, (CAC) was tested. The modified polyacrylamide is a typical hydrophobically associating polymer, reaching a CAC at a mass concentration of about 0.25% (by weight). It is found from the friction test that the optimum concentration of the drag reducer is about 0.05% in fresh water, and the highest drag-reducing rate reaches as high as 72%. In addition, high concentration and high viscosity of drag reducer may impart negative impact on drag reduction rate in fresh water. While in brine, the optimum concentration is about 0.1%, and the highest drag-reducing rate is 68.4%. A high concentration has little negative impact on drag reduction rate, because viscosity is always very low. From the SEM images, it can be seen that the polymer can form network structure in fresh water. Above the CAC concentration, the network structure is significantly denser than that below the CAC concentration, but this is not conducive to the drag-reducing rate. In practical application, we always recommend using concentrations below CAC. Graphical Abstract