| In this paper, the micellization of cetyltrimethyl ammonium chloride(CTAC) cetyltrimethyl ammonium bromide (CTAB) and counterions, such as trans-Ortho-Methy sodium cinnamate (tran-Ortho-MCANa, abbr.OMCA),trans-Mata-Methy sodium cinnamate (trans-Mata-MCANa, abbr.MMCA) and trans-Para-Methy sodium cinnamate (trans-Para-MCANa, abbr.PMCA) was studied. The rheological properties of the micelles were investigated. The new stable viscoelastic drag reducing micelle systems were obtained by mixing cationic Gemini surfactant (propyl (double octadecyl dimethyl ammonium chloride), abbr.18-3-18) with sodium salicylate (NaSal), potassium hydrogen phthalate (PHP) and sodium cinnamate (CA) respectively. The rheological properties and drag reducing behaviors of the above micelle systems were investigated. The main conclusions were made as follows.1) Novel viscoelastic micelle systems of CTAC/MCA and CTAB/MCA could be formed under certain conditions. The effects of surfactant and counter-ion concentration on micelle formation were inllustrated. Relative viscosity of CTAB/MCA micelle solutions appeared a peak value, when the molar ratio of CTAC to OMCA, MMCA was about 0.75 and the molar ratio of CTAC to PMCA was about 1.0. The effect of temperature on the viscosity curves was significant, and the viscoelasticity of micelle disappeared when the temperature reached 60℃The results of rheological study showed that these micelle systems possessed good properties of shear-thinning, viscoelasticity and thixotropy. The effect of position of substituting group of counterions on the rheological properties of CTAB/MCA micelles was significant, and the CTAB/PMCA micelle system possessed stronger structure under same conditions.2) Novel micelle systems could be formed by Gemini surfactant 18-3-18 and NaSal, PHP, CA. These micelle systems possessed good properties of shear-thinning and viscoelasticity, and with the increase of micelle concentration the viscoelasticity of the micelle solutions increased. The flow curves of the micelle systems could be described by power-law model.3) The viscoelastic 18-3-18/NaSal,18-3-18/PHP and 18-3-18/CA micelle systems posseses good drag reduction behaviour. The drag reduction percentage for these micelles increased with the increase of Generalized Reynolds number (ReM). The relationship between Fanning friction factor and generalized Reynolds number was obtained. When the molar ratio of 18-3-18 to NaSal, PHP, CA was 7.5mM/15mM, the maximum drag reduction percentage was 82.3%,81.1% and 58.9% in smooth pipe respectively. The drag reducing behavior of 18-3-18/NaSal and 18-3-18/PHP micelles was better than that of 18-3-18/CA micelle.The studies in this paper provide good basis for the future study and application of drag reducing surfactant micelles. |
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