Demulsification of oil-in-water emulsions using hyperbranched poly(amido amine) demulsifiers with 4,4-diaminodiphenyl methane as initial cores

Hyperbranched poly(amido amine) demulsifier (PDDM) was synthesized by a modified one-pot method with 4,4-diaminodiphenyl methane as the central core and ethylenediamine as the interior branches. The structure of the demulsifier was confirmed by proton nuclear magnetic resonance and Fourier transform infrared. The effects of the temperature and PDDM concentration on the demulsification performance were investigated, and PDDM performance was compared to that of the hyperbranched demulsifier with 1,3-propanediamine as the central core. When the emulsions were treated with the demulsifier concentration of 50 mg L-1 at 60 degrees C for 120 min, the light transmittance and removed total organic content of the aqueous phase reached 87.4 and 99.72%, respectively. At the optimal demulsification temperature of 60 degrees C, the surface tension reduction and the critical micelle concentration were 27.38 mN m(-1) and 1.30 x 10(-3) mol L-1, respectively. The combination of surface tension and interfacial tension measurements and the analysis of micrographs and particles sizes provide evidence for the possible demulsification mechanism. The excellent demulsification performance of the hyperbranched demulsifier indicates that it has great potential for use in the demulsification of oil-in-water emulsions. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48846.