Study On The Synthesis And Properties Of Novel Surfactants

Bolaamphiphiles are molecules with two polar groups connected by one or two hydro-phobic chains.Polypropylene glycol bis-phosphate(PPGBP) and polypropylene glycol bis -sulphate are such bolaamphiphiles.PPGBP was synthesized using polypropylene glycol(PPG)as raw material,polyphosphoric acid(PPA) as phosphaticing reagent.The relative weight per-cent of the PPGBP and dis-polypropylene glycol phosphate (DPPGP) were determined bypotentiometric method.The polypropylene glycol phosphate were neutralized by potassiumhydroxide .The effects of the reaction temperature, reaction time, molar ratio on the product-ivity of polypropylene glycol di-phosphate and the relative weight percent of PPGBP are dis-cussed in detail. Through orthogonal experiment, the optimal process conditions were deter-mined: n(PPA):n(PPG)=1.5:1, reacting temperature 70 ℃ for 5 hours. Under these conditions,the rate of ester yield reached 92.68%,the weight percent ratio of PPGBP and DPPGP was8.25:1.Polypropylene glycol bis-sulphate(PPGBS) was synthesized from polypropyleneglycol,and polypropylene glycol was esterified by chlorosulfonic acid and further neutralizedby sodium hydroxide.The effect of the ratio of chlorosulfonic acid to polypropylene glycol,thetempration and reaction time on the yield and the composition of PPGBS wereinvestigated.The optimum reaction conditions are determined,mole ratio of chlorosulfonicacid to polypropylene glycol is 2.04:1,reaction time is 2.25h at 30 ℃, and the HSO3Cl,s addtime is 1.5h.The PPG conversion is 94.60%,the content of PPGBS is 82.35%. The critical micelle concentration(cmc)of PPGBP,PPGBS were determined bymeasuring the surface tension.Γ∞ and A∞ was got by formula of Gibbs,it is found that theadsorption amount was smaller,the area of average molecule was larger,these due to theirreverse U-shape conformation in the surface.The effects of salinity,temperature and the lengthof hydrophobic chain on cmc were studied.The results revealed that the novel surfactant hadlower surface activity than traditional surfactants.The cmc of surfactant was stronglydependent on the salinity and the length of hydrophobic chain,as the salinity increases or thelength of hydrophobic chain was longer,the surface activity became higher, The effect oftemperature on cmc was not evident.The results about the behaviors of adsorption ofPPGBP,PPGBS on calcium carbonate surface showed that, the adsorption isotherm of PPGBPwas LS type while the PPGBS was L type.