Abstract: In this paper, we prepared a polymeric composite from a new self-repared sulfobetaine amphoteric surfactant and a polyacrylamide with 25 million relative molecular mass, and investigated the effect of the as-prepared polymeric composite on its surface performance and interfacial performance. Dropping volume method was used to determine the surface tension of the solution. The results show that the critical micelle concentration increases by adding polyacrylamide and the surface tension of the solution is greater than that of the single surfactant solution. Furthermore, the surface tension of the system increases significantly with the increase of salinity. The spinning drop interfacial tension was determined. It is shown that the water/crude oil interfacial tension increases with the increase of polymer concentration but increases indistinctively with the increase of salinity. When the polymer concentration is 1.5 g/L and the surfactant concentration is 0.3 g/L, water/crude oil interfacial tension of Gudao crude oil and Gudong crude oil from Shengli oil field achieves ultra low magnitude at 10-3 mN/m. Finally, we come to determine the emulsifying performance by diversion time method. The results show that the diversion time extends with the increase of polymer concentration. And we also investigated emulsifying property at 75 ℃, 85 ℃, 95 ℃, respectively. It is found that diversion time shortened with the increase of temperature.

Key words: surfactant, polyacrylamide, composite, surface tension, interfacial tension, emulsifying performance