Preparation and properties of a novel surfactant constructed by electrostatic interactions
Taking stearic acid as the raw material,N-(2-(dimethylamino)ethyl)stearamide(C18N2N)was synthesized.A new surfactant was prepared by mixing C18N2N and cinnamic acid(TA)with fixed ratio.This surfactant was formed by non-covalent electrostatic interactions,which avoided complicated synthetic procedures.The surface activity and rheological properties of the surfactant were investigated with a surface tensiometer and a rheometer.The critical micelle concentration(cmc)and the surface tension at cmc(γcmc)of the surfactant were 0.11 mmol/L and 32.4 mN/m,indicative of strong aggregation and adsorption ability.The maximum amount adsorbed(Γmax)and the minimum molecular area occupied(Amin)were 2.77 μmol/m2 and 0.6 nm2.Wormlike micelles were formed at the concentration of 25 mmol/L.When the concentration was over 100 mmol/L,the zero-shear viscosity(η0)abruptly increased and then reached the maximum value for the surfactant of C18N2N/TA containing 150 mmol/L TA.The solution viscosity was as high as 1 761.38 Pa·s.The effects of temperature on the rheological behavior were also considered.With the increase of temperature,the viscosity gradually increased.And when the temperature reached 40℃,η0 of the solution with the concentration of 100 mmol/L achieved the maximum value of 1 370.386 Pa·s.When the temperature continued to rise,η0 began to decrease with further increasing temperature.A remarkable viscosity of 305.55 Pa·s was still remained at 50℃.The viscoelastic solutions showed good temperature resistance and shear resistance.The surfactant solutions applied as the fracturing fluid were also investigated.This surfactant also showed excellent sand-carrying performance,and the settling rate of the sand was merely 0.26 cm/min.This surfactant could be simply prepared and showed excellent performance,which expanded the preparation and application field of novel surfactants.
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NSTL
万方数据
维普
