Synthesis and performance evaluation of salt-tolerant amphoteric polyacrylamide
Acrylamide(AM),2-acrylamido-2-methylpropanesulfonic acid(AMPS)and dimethyl-diallyl ammonium chloride(DMDAAC)as monomers to prepare amphoteric polyacrylamide,the salt resistance was tested.The result showed that qualitative analysis by infrared spectroscopy and nuclear magnetic reso-nance confirmed that the synthesized product was the target product,and AMPAM can maintain a viscosity of more than 10 mPa·s in 20 000 mg/L NaCl solution and 10 000 mg/L CaCl2 solution.Scanning elec-tron microscopy was used to observe the changes in the microscopic morphology of AMPAM solution with 0.5%concentration at different salinity.Due to the serious weakening of intermolecular attraction and repulsion,the molecular chains began to converge and curl,forming a large number of molecular clusters and eventually forming a complete block structure.At this time,the viscosity of the solution changed little and gradually became stable.