Study On The Properties Of The Mixed Systems With Betaines

Betaine is a typical zwitterionic surfactant which has good compatibility with many kinds of surfactants and has the potential applied value. In this dissertation, betaine was selected for the study on the properties of mixed system containing betaine and lipopeptide as well as polymer. The results include as followings.1) Interfacial tension between crude oil and combinational system of N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate(SDDAB)-lipopeptide.The ability of different alkali in reducing interfacial tension in order is NaOH>Na2SiO3>Na2CO3>NaHCO3; the order of different weak mixed alkali is Na2CO3/Na2SiO3>Na2SiO3/NaHCO3> Na2CO3/NaHCO3 With mixed alkali Na2CO3/Na2SiO3 an evident coordination effect is observed with a lowest interfacial tension approaching to 10-4 mN/m, and the optimum mass ratio for SDDAB/lipopeptide is 1:1. The interfacial tension of SDDAB-lipopeptide / Na2CO3/Na2SiCO3 system increases with the ascension of hydrolyzed polyacrylamide (HPAM) concentration.2) The interaction between lipopeptide Surfactin C15 and SDDAB. The critical mi cell concentration (CMC) decreases with the increase of Surfactin C15 content in mixe d system. While the molar concentration of Surfactin C15 is 70%, the lowest CMC is obtained. Theoretic calculation shows that synergism is most obvious when the mole f raction of Surfactin C15 is 0.70.3) The interaction between polymer and different betaines. In the mixed system o f polyacrylamide(PAM) and betaine, N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfo nate(SDDAB), N-tetradecyl-N,N-dimethyl-3-ammonio-l-propanesulfonate(STDAB), N- he xadecyl -N,N-dimethyl-3-ammonio-1-propanesulfonate(SHDAB) have the same hydrophil ic group, the critical aggregation concentration(CAC) is 7.23×10-2 mM,5.70×10-3 mM, and 2.90×10-3 mM respectively, and the strength of interaction between polymer and b etaine varies according to the length of hydrophobic chain and it's order is SHDAB> STDAB> SDDAB. The CAC of mixed system of N-dodecyl-N,N-dimethyl-2-ammonio-acetate(C12BE) and PAM is 5.82×10-2 mM which is lower than the CAC of mixed sys tem of SDDAB and PAM. In the mixed system of SHDAB and PAM, CAC decreases from 1.05r10-2 mM to 4.41×10-4 mM when the mass fraction of PAM increases from 0.4 wt% to 1 wt%. The concentration and molecular weight of PAM could also affect the interaction between PAM and betaines 4) The interaction between polymer and lipopeptide as well as between polymer and lipopeptide-betaines. In the mixed system of Surfactin C15 and PAM, CAC is 1.90×10-3 mM and 4.90×10-4 mM when the mass fraction of PAM is 0.4 wt%and 0.8 wt%. The greater the concentration of PAM. the lower the CAC and the stronger the interaction. Surfactin C15 could effectively promote the interaction between PAM and SDDAB, when the mass concentration of PAM is 0.8 wt%. the malar ratio of Surfactin C15/SDDAB is 2:1, Surfactin C15 could reduce CAC of the mixed syetem of SDDAB/PAM from 7.23×10-2mM tol.19×10-5 mM.