Study On Synthesis And Properties Of Glycerol Polyoxyethylene Ether Fatty Acid Ester

Polyoxyethylene-type nonionic surfactants are non-poisonous and low-irritating.They do not dissociate in water and possess good stability which can not be affected by electrolyte,strong acid and strong base,and possess high application value.Among them glycerol polyoxyethylene ether fatty acid ester is a specific polyoxyethylene-type nonionic surfactant with good properties.However,the physicochemical properties of the domestic products are inferior to those of the imported products at present.This in combination with the scarcity of the systematic theoretical research on the relevant properties both at home and abroad limits its further development and applications.Due to these reasons,a series of PEG-7 fatty acid glycerides（abbreviated as PEG-7-C_n）of different carbon chain length(C₁₀,C₁₂,C₁₄)were synthesized.Their surface chemical properties and basic application properties were studied.The quantitative measurement system of degreasing and fatliquoring effects of surfactants on the skin surfaces was established to study the degreasing and fatliquoring properties of PEG-7-C₁₂.Then,O/W emulsions were prepared by using PEG-7-C_n as the emulsifiers,and the effects of each factor on the stability of the O/W emulsions were theoretically explored to obtain the optimum process conditions for the preparation of the O/W emulsions.Finally,based on the above study,PEG-7-C₁₂ was applied to the formulation of makeup removing emulsions.Related properties of the sample of makeup removing emulsions were measured.The main contents and results of this work are as below:Fatty acids of different carbon length(C₁₀,C₁₂,C₁₄)and PEG-7 glycerol polyoxyethylene ether were used as the raw materials to synthesize PEG-7-C₁₀,PEG-7-C_12,PEG-7-C₁₄ by esterification without water-carrying agent,in which p-toluenesulfonic acid was used as the catalyst.The optimum process conditions for the synthesis obtained by single factor test and orthogonal test were as follows:the reaction temperature of 150℃,the reaction time of 5 h,the catalyst（p-toluenesulfonic acid monohydrate）dosage of 0.6%of the total mass of the reactants,the reactant molar ratio of n（fatty acid）:n（PEG-7 glycerol polyoxyethylene ether）=0.7:1.Under the optimum conditions the esterification rates all exceeded 98.5%.The generation of the target products was proved by the FT-IR and MS characterization.Comparison between the as-synthesized products and the commercially available products was carried out.It was shown the physicochemical properties of the as-synthesized products were better than those of the domestic products and similar to those of the imported products.The basic properties of PEG-7-C_n were studied,and the results showed that the carbon length of the hydrophobic group of PEG-7-C_n was longer,the lower cmc was,and the higherγ_cmcwas.The cloud points of PEG-7-C_n all satisfied their normal use.The detergency properties and dispersing properties of PEG-7-C_n were all relatively good.The wetting properties of PEG-7-C_n were all ordinary.The foam stability properties of PEG-7-C_n were all relatively poor.The emulsifying properties of PEG-7-C₁₂and PEG-7-C₁₄were excellent.The foaming property of PEG-7-C₁₂ was relatively good.Glycerol polyoxyethylene ether fatty acid ester possesses a degreasing property as most surfactants do,and has a fatliquoring property by virtue of the lipid-like structure when it is excess relative to the oil phase.PEG-7-C₁₂ was selected as the study object,and the quantitative measurement system of degreasing and fatliquoring effects of surfactants on the skin surfaces was established by using pigskin as the test skin.The sebum decrease rate of the skin surfaces containing different oils after washing by the PEG-7-C₁₂aqueous solution was measured,which confirmed that the degreasing property of PEG-7-C₁₂ was excellent.The sebum content of the skin surfaces without lipid after washing by the PEG-7-C₁₂aqueous solution was measured,with a microscope to photograph the morphology of the skin surfaces,which confirmed that PEG-7-C₁₂ possessed a fatliquoring property,a lipid membrane would be formed when it acted on the skin surface.The sebum decrease rate of the skin surfaces containing olive oil after washing by the sodium laurate/PEG-7-C₁₂ compounded system aqueous solution was measured.At the same time,human skin was used as the experimental subject,the MMV（moisture measuring value）and TEWL（trans epidermal water loss）before and after washing were measured when the mass fraction of PEG-7-C₁₂was 0%and 3%respectively,which confirmed that PEG-7-C₁₂ could prevent the skin moisture from loss by fatliquoring effect so as to improve the skin feeling after washing by soap-based surfactants.PEG-7-C_n was used as the emulsifiers to prepare the O/W emulsions,the influence of the emulsifier type on the O/W emulsions was firstly investigated.The results showed that the O/W emulsions prepared by using PEG-7-C₁₂ as the emulsifiers possessed the best stability.By the observation and fluorescent staining methods,the type of the emulsions was confirmed to be O/W.The influences of the emulsifying temperature,stirring rate,emulsifier dosage,oil-water volume ratio,polymer type and added amount of polymer on the stability of the O/W emulsions were investigated by single factor test,the droplet size of the O/W emulsions was examined via the laser droplet size analyzer and the super-high magnification lens zoom3D microscope,the viscosity,storage modulus and loss modulus were measured via the rotational rheometer.The results showed that the optimum process conditions for the preparation of the O/W emulsions were as follows:the emulsifying temperature of 80℃,the stirring rate of 500 r·min^-1,the emulsifier PEG-7-C₁₂ dosage of 5 wt%,the oil-water volume ratio of 1:1,the added amount of xanthan gum of 0.2 wt%.The long-term stability of the O/W emulsions prepared with different oil phase under the optimum process conditions was tested.The results showed that they all possessed good long-term stability.Based on the above study,a formulation of makeup removing emulsions was designed by using PEG-7-C₁₂ as the emulsifiers and degreasing agents,then the physicochemical properties,degreasing property,makeup removing effects and skin feeling of the sample of makeup removing emulsions were measured.The results showed that the p H was approximately 6.38,the viscosity was 3029 m Pa·s,the stability was good,the degreasing property and makeup removing effects were excellent,the skin feeling was good.