Synthesis,Characterization Of Hydrocarbon Surfactant With Pvac-and Formation Of C/W Emulsion

For the system of C/W emulsion formatted with supercritical carbon dioxide(scCO2),water and surfactant,fluorocarbon-and siloxane-based surfactants with good emulsifying capacity may be expensive and not environment-friendly;Moreover,the stabilization time of C/W emulsion formatted by the commercial hydrocarbon surfactants may be short and the volume fraction of CO2 phase(dispersed phase)may be no more than 70%.So the amphiphilic hydrocarbon surfactant with poly(vinyl acetate)(PVAc)and poly(dibutyl maleate)(PDBM)or only poly(vinyl acetate)(PVAc)as C0O-philic group and poly(dimethylaminoethyl methacrylate)(PDMAEMA)as hydrophilic group were designed and synthesized.C/W emulsion was successfully formatted using the high pressure emulsification device and the influence of the structure of CO2-philic group,hydrophilic/CO2-philic balance(HCB)and proportion of CO2 and water(v/v)on the emulsifying properties and the stabilization time of C/W emulsion were investigated.It was shown that CO2-H2O systems could be emulsified by PVAc-alt-PDBM-b-PDMAEMA effectively to obtain high internal phase(80%)emulsion that remained stable longer than 48 h,which improving the stability compared with PVAc-b-PDMAEMA.The surface tension results evidenced that PVAc-alt-PDBM-b-PDMAEMA could make a greater reduction in surface tension of the polymer,lowering polymer-polymer interaction and improving the solubility in CO2.Furthermore,another surfactant with PVAc-alt-PDBM as CO2-philic group and poly(ethylene glycol)(PEG)as hydrophilic group was synthesized,which could emulsify CO2-H2O systems effectively to obtain high internal phase(90%)emulsion that remained stable longer than 24 h.The stability of the emulsion may be improved with proper HCB and higher pressure.