Synthesis And Anti-emulsification Mechanism Of Fluorinated Multi-block Copolymer With Dumb Bell-shaped Structure

Water separation performance is an important quality index of the anti-emulsifier.As report goes,the demulsifier with hyperbranched structure was of the ability of strong hydrophilic,wetting and penetrating,which made it better than that of the direct type demulsifier.Water separated by the demulsifier with ethers of straight chain was more clear and transparent.Besides,during the process of demulsification,the anti-emulsifier shouldn?t be separated away by the water.The anti-emulsifier should be not only efficient,but oil-soluble and chemically inert.Bsides,fluoropolymers were of high chemical inertia,thermal stability and excellent weather resistance,as well as hydrophobic oleophobic characteristics.Given this,we synthesized three fluorine-containing multi-block copolymers with the dumbbell-shaped structure(FMCDSs).We studied the anti-emulsifying properties and mechanism of the FMCDSs.The first section of this thesis: the synthesis and structural characterization of FMCDSs.Firstly,the hyperbraned polyether consisting of a linear PEG block and two hyperbranched PG blocks was prepared via anionic ring-opening multibranching polymerizations(AROMBP)combined with slow monomer addition.The polyether(PG-b-PEG-b-PG)was block polymer with Dumbbell-shaped structure.Then PG-b-PEG-b-PG was modified with trifluoroethyl methacrylate by atom transfer radical polymerization(ATRP).Three kinds of FMCDSs(FMCDS-1?FMCDS-2?FMCDS-3)containing different fluorine by adjusting the ratio of monomer to initiator.In addition,we characterized the structures of FMCDSs by GPC ?1HNMR?13CNMR 19 FNMR and so on.The second part of this thesis: the anti-emulsifying behavior and mechanism of FMCDSs in 150 SN base oil-water system were studied.We studied the anti-emulsifying behavior of FMCDS-1 ? FMCDS-2 and FMCDS-3 with different concentrations.It was found that FMCDS-1 with a lower degree of fluorination achieved a basic separation of 150 SN base oiland water in 50 seconds at a mass concentration of 100 mg·L-1.The optimum anti-emulsifying properties of FMCDS-2 and FMCDS-3 were 200 mg·L-1,300 mg·L-1,respectively.The corresponding time was 53 s and 101 s respectively.The change of interfacial tension was not the major factor that FMCDSs can effectively improve the anti-emulsification properties of 150 SN base oil-water system.The 150 SN base oil-water system was an elastic system.The variation law of dilational elasticity was consistent with time that needed to seperate the crude oil and water.The shorter the time it needed,the better the anti-emulsification properties the lower the dilational elasticity.FMCDSs in the oil-water aggregate in the interface of oil and water reducing the interface film strength,making it difficult to form a stable emulsion,and damaging the local structure of the interface film to achive demulsification.