Synthesis And Properties Of Novel Starch Based Surfactants

Traditional surfactants come from petrochemical industry,but petroleum is a non-renewable energy source,and will cause a lot of environmental problems.It has become a new trend to use natural and cheap starch as raw material to prepare surfactants.In this thesis,cassava starch is used as raw material.Dodecyl dimethyl betaine starch-based surfactant,dodecyl succinic anhydride starch-based surfactant and dodecyl dimethyl betaine-dodecyl succinic anhydride starch-based surfactant were prepared by wet process.The preparation technology,properties and washing application of three kinds of starch-based surfactants were studied.The main research conclusions of this thesis are as follows:1.The optimum preparation process of BS starch-based surfactant is as follows:the addition amount of BS-12 is 40%,the addition amount of urea is 3%,the addition amount of Na₂Si O₃ is 1%,the reaction temperature is 85℃,the reaction time is 20min.Under these conditions,the surface tension is 25.11 m N·m^-1（solid content 2%,25℃）,the viscosity is 4958 cp（solid content 5%,25℃）,and the emulsification rate is 100%（solid content 5%）.2.The optimum preparation technology of DDSA starch-based surfactant is as follows:the dosage of DDSA is 5%,the p H is 10,the reaction temperature is 45℃,the reaction time is 120 min.Under these conditions,the surface tension is 11.28m N·m^-1（solid content 1%,25℃）,the viscosity is 46.27 cp（solid content 1%,25℃）,the degree of substitution is 0.012,and the reaction efficiency is 42.22%.3.The optimum preparation process of BS-DDSA starch-based surfactant is as follows:the addition amount of BS-12 is 30%,the catalytic dose of BS-DDSA is5%,the reaction temperature is 90℃,and the reaction time is 30 min.Under these conditions,the surface tension is 23.58 m N·m^-1（solid content 1%,25℃）,the viscosity is 1827 cp（solid content 3%,25℃）and the degree of substitution is 0.023.4.Through the performance test of three kinds of starch-based surfactants,the results are as follows:DDSA starch-based surfactants has the best surface activity,followed by BS-DDSA starch-based surfactants;DDSA starch-based surfactants has the best emulsifying property,followed by BS starch-based surfactants.BS-DDSA starch-based surfactants shows the best salt resistance and acid and alkali resistance,followed by BS starch-based surfactants.BS starch-based surfactants and BS-DDSA starch-based surfactants have synergistic gain with sodium dodecyl sulfate.BS starch-based surfactant is dilatant plastic fluid,DDSA starch-based surfactant and BS-DDSA starch-based surfactant are pseudoplastic fluid.Compared with the commonly used surfactants sodium dodecyl benzene sulfonate,SDS,dodecyl dimethyl betaine,these three starch-based surfactants have better surface activity,emulsification performance and higher viscosity.5.Starch-based surfactant and cassava starch were characterized by polarizing microscope,FT-IR,SEM and XRD,and the following results were obtained:Compared with cassava starch,XRD and polarizing cross characteristics of DDSA starch-based surfactants had no obvious changes.The crystallites of BS starch-based surfactants and BS-DDSA starch-based surfactants changed from A type to V type and polarizing cross disappear.SEM showed that the surface morphology of starch particles was damaged to some extent.FT-IR indicated that the starch-based surfactant introduced a new group.6.The preparation and properties of starch-based detergent:When the total amount of detergent is 100 g,the best addition amount of LAS is 1.1 g,the best addition amount of BS starch-based surfactant is 4.4 g,and the decontamination coefficient is 1.81.The optimal addition amount of LAS is 2.2 g,the optimal addition amount of DDSA starch-based surfactant is 3.3 g,and the decontamination coefficient is 1.71.The optimal addition amount of LAS is 2.2 g,BS-DDSA is 3.3g,and the decontamination coefficient is 1.74.