Polymeric surfactants for enhanced oil recovery. Part I—critical micelle concentration of some ethoxylated alkylphenol—formaldehyde nonionics

Abstract

Four low molecular weight nonionic polymeric surfactants were prepared by condensing octyl-, dodecyl-, tetradecyl-and hexadecylphenol with paraformaldehyde, and then reacting the resulting resins with ethylene oxide to obtain products with the desired degree of ethoxylation. The molecular weights of the prepared alkylphenol-formaldehyde resins (prior to ethoxylation) were determined by vapour pressure osmometry.The surface tensions of aqueous solutions of these nonionic polymeric surfactants were determined by using the spinning drop method. Plotting the surface tensions obtained versus the logarithm of concentrations resulted in two lines: the pre-CMC (CMC = critical micelle concentration) line (the linear portion below the CMC value) and the post-CMC line (the linear portion above the C M C value). Least squares regression analysis was performed to get the best equation for each of the two lines. Solving these two equations simultaneously resulted in the value of the CMC and the corresponding surface tension (yCMC) for each surfactant of the four polymeric nonionic groups.The CMC values obtained for these polymeric surfactants are of the same order of magnitude obtained for monomeric and other polymeric nonionic surfactants.

Polymeric surfactants for enhanced oil recovery. Part V: Prediction models for the effect of temperature and length of polyoxyethylene chain or hlb on surface and thermodynamic properties of some ethoxylated polymeric nonionics

“…The methods of preparation and characterization of these compounds have been described previously. 6 A generalized formula of these surfactant groups is shown in Fig. 1, and complete characterization is given in Table 1.…”

Effect of temperature and pH values on aggregation behavior of polymeric surfactants in aqueous solution

“…5,6 With the change of solution conditions such as solvent, electrolyte, temperature, and pH values, they would also make complex conformational changes, which may have great influence on their application performance of interfacial activity, viscosity, and emulsification. [7][8][9][10] However, few studies have so far been conducted on the effect of temperature and pH value changes on the aggregation behavior of polymeric surfactants because of their complicated influences, especially for hydrophilic polymeric surfactants.…”