Demulsification Performance and Mechanism of Dumbbell-shaped Fluoro Copolymers in Diesel Emulsions

The demulsification performance of three fluorinated multi-block copolymers with dumbbell- shaped structure (FMCDSs) containing different hydrophilic polyethylene glycol (PEG) segment in diesel oil (0#)/water emulsion were investigated, and compared with those of polyether demulsifiers and dumbbell-shaped polyglycerol-PEG (PBG) polymers. The results showed that these FMCDSs exhibited better demulsification performance than the hydrocarbon polymers. PEG segment length in FMCDSs had a significant effect on demulsification performance. Especially, the synthesized demulsifier containing PEG- 4000 segment showed good diesel separation efficiency, and the oil separation efficiency reached 95% within 30 min at a dosage of 300 mg/L (30℃). In addition, based on the results of interfacial tension and interfacial dilation rheology measurements, it was found that the FMCDSs could effectively adsorb on the diesel-water interface, and the fluorined groups were the major factor in producing good demulsification properties. © 2019, Editorial Office of FINE CHEMICALS. All right reserved.