Preparation,Properties And Applications Of Polymeric Surfactants Based On Epoxidized Soybean Oil Grafted Hydroxyethyl Cellulose

Cellulose-based polymeric surfactants have drawn much attention because they present many novel performances,such as solubilization,dispersion,foaming,and emulsification.However,there are still some problems such as surface activities and the use of petrochemical resources.In this paper,novel cellulose-based polymeric surfactants（H–ESO–HEC–Na）with excellent surface activity were prepared using epoxidized soybean oil grated hydroxyethyl cellulose.The preparation,properties and applications of H–ESO–HEC–Na were investigated.Oil-in-water soybean oil（SO）emulsion（SO/H2O emulsion）and water-in-oil acrylated epoxidized soybean oil（AESO）emulsion（AESO/H₂O emulsion）were prepared by H–ESO–HEC–Na as emulsifier.The stability and rheological properties of these emulsions was studied.The PR–AESO porous materials with high mechanical properties were prepared by emulsion template method and free radical polymerization.The oil sorption capacities of PR–AESO porous materials were studied.Epoxidized soybean oil grafted hydroxyethyl cellulose（ESO–HEC）was synthesized through the graft reaction between epoxidized soybean oil（ESO）and hydroxyethyl cellulose（HEC）using stannic chloride（SnCl4）as catalyst in dimethyl sulfoxide（DMSO）.Cellulose-based polymeric surfactants（H–ESO–HEC–Na）were prepared by hydrolysis of ESO–HEC with a base in order to adjust its amphiphilicity.Five H–ESO–HEC–Na with different molecure weight and ESO grafting degree was prepared by adjusting the mass ratio of HEC and ESO.The structure of H–ESO–HEC were characterized by FT-IR,¹H NMR,¹³C NMR,and DSC analysis.The GPC result showed that the M_w of H–ESO–HEC–Na（I^V）ranged from 2.71×10⁵ to 8.28×10⁵ Da with the mass ratio improved from 1:1 to 5:1.When the ESO grafting degree reached 25.8%,the glass transition temperature（Tg）of H–ESO–HEC–Na increased from-25.81 ^oC to-21.48 ^oC.When the surfactant concentration reached its critical micelle concentration value（CMC）,the surface tensions of H–ESO–HEC–Na（I^V）were 26.329,28.876,27.833,26.365 and 26.941 m N/m.Furthermore,the CMC values of H–ESO–HEC–Na（I^V）decreased from 1.053 g/L to 0.157 g/L with the increasing Mw.H–ESO–HEC–Na can reduce heptane/water Interface tension to 9.8 mN/m.Rheological measurements indicated that the H–ESO–HEC–Na solutions changed from pseudo plastic property to Newtonian with increasing shear rate.Analysis of the equilibrium surface tension of H–ESO–HEC–Na with different molecular weights was carried out at different pH and concentration by using Wilhelmy plate method.The results showed that the H–ESO–HEC–Na（I^V）was effective at lowering the surface tension of water in aqueous solution（8¹3）.Particularly,the minimum surface tension of H–ESO–HEC–Na（II^V）could reach to 25.87²8.04 mN/m at pH 10.The CMC values of the H–ESO–HEC–Na（I^V）increased with the increasing pH and decreased with the increasing molecular weight at the same pH,as expected.Analysis of the dynamic surface tension of H–ESO–HEC–Na with different molecular weights was carried out at different pH and concentration by using pendant drop technique.The result showed that the surface tension of H–ESO–HEC–Na decreased slowly over time at different CMC concentrations,until the H–ESO–HEC–Na reaced adsorption equilibrium at the air/H2O interface.The adsorption behavior of H–ESO–HEC–Na at the air/solution interface was analyzed with diffusion control mechanism by using the Ward and Tordai equation.The effective diffusion coefficients of H–ESO–HEC–Na increased with pH and molecular weight,respectively.Furthermore,H–ESO–HEC–Na with higher molecular weight weights had larger micelles.An oil-in-water emulsion（SO/H₂O emulsion）stabilized by H–ESO–HEC–Na as emulsifier was investigated by using an ultrasonic method.The influence of H–ESO–HEC–Na concentrations on the stabilities of SO/H2O emulsions was examined.When the H–ESO–HEC–Na concentration was 0.4 wt%,the emulsion remained stable.Moreover,the stability of SO/H₂O emulsions prepared by H–ESO–HEC–Na was superior to the CMC–and HEC–stabilized emulsions.The adsorption amounts of H–ESO–HEC–Na at the oil–water interface increased when the H–ESO–HEC–Na concentrations in the aqueous phase increased.The mean droplet sizes of the emulsions decreased by increasing the H–ESO–HEC–Na concentration and extending the ultrasonic time.The rheological property revealed that the apparent viscosity of the H–ESO–HEC–Na stabilized SO/H₂O emulsions increased when the H–ESO–HEC–Na concentrations increased and the all emulsions displayed predominantly elastic behaviors.A water-in-oil emulsion（AESO/H₂O emulsion）stabilized by H–ESO–HEC–Na as emulsifier was investigated by using mechanical stirring method.The influence of H–ESO–HEC–Na concentrations on the stabilities of AESO/H₂O emulsions was examined.When the H–ESO–HEC–Na concentration was 1.2 wt%,the emulsion remained stable for more than 200 days.The rheological property revealed that the AESO/H₂O emulsions displayed Newtonian properties at low shear rate and non-Newtonian properties at high shear rate.And the emulsions showed a typical viscous gel phenomenon.Then,PR–AESO porous materials were prepared by free radical polymerization of AESO using emulsion template.The thermal stability,pore size distribution,mechanical property and oil absorption properties of PR–AESO porous materials were investigated.TG test showed that RP–AESO porous materials had high thermal stability.With the increasing concentration of H–ESO–HEC–Na in the AESO/H2O emulsion,the pore density of RP–AESO porous materials increased and the average pore size decreased.RP–AESO–1.5 porous materials has a uniform pore size distribution,and the average diameter is about 7μm.The water contact angle of PR-AESO porous materials was up to 134°and displayed strong hydrophobic properties.The compressive strength of RP–AESO–0.4,RP–AESO–0.8,RP–AESO–1.2 and RP–AESO–1.5 porous materials were 66.85,66.51,47.03,and 41.12 MPa,respectively.And the compressive strength of RP–AESO porous materials decreased with the increase of H–ESO–HEC–Na concentration in in the AESO/H2O emulsion.The oil absorption properties of RP–AESO–1.5 porous materials for dichloromethane,cyclohexane,heptane,gasoline and soybean oil were 3.20,1.52,2.35,2.80 and 2.42 g·g^-1,respectively.It showed excellent oil absorption properties and accorded with Quasi-first-order adsorption kinetic model.