Effect of hydrophobic group content on the properties of betaine-type binary amphiphilic polymer

With the development of high salinity reservoirs, amphiphilic polymers with salt thickening behavior have gained increasing attention. In this work, a betaine-type binary amphiphilic polymer PAMA-n with different hydrophobic group contents was synthesized and characterized. The influencing mechanism of different hydrophobic group contents on properties of PAMA was studied by means of viscometer, rheometer, surface tension meter, simultaneous thermal analyzer and fluorescence spectrophotometer. The experimental results showed that the betaine group and hydrophobic group were located in the same association monomer of the PAMA. PAMA was a betaine-type amphiphilic polymer with strong association, high solubility and certain surface activity. Higher hydrophobic group content could enhance the ability to reduce surface tension and the association function between hydrophobic groups of PAMA. The viscosity, thermal stability and viscoelasticity could be improved with the increase of hydrophobic group content. Meanwhile, the PAMA with higher hydrophobic group content showed a better salt thickening behavior. •A betaine-type binary amphiphilic polymer PAMA-n was synthesized.•Influence mechanism of hydrophobic group content on property of PAMA was studied.•PAMA in brine water showed a better salt thickening behavior.