Synthesis And Properties Of Hydrophobically Modified Amide Derivatives Of Carboxymethyl Starch

Hydrophobic modified products of starch and its derivatives have good physical and chemical properties.They are widely used in petroleum exploiting,paper making,soil improvement,wastewater treatment,etc.And they show promising prospects in various areas. In this thesis,a series of amide derivatives of carboxymethy starch(ACMS)were synthesized through the reaction of carboxymethyl starch(CMS)and different amines which were selected as the hydrophobic reagent.Synthesis and properties of ACMS were studied.ACMS with different degree of substitution(DS)of hydrophobic group was prepared by reaction of CMS with fatty amine(FA),such as isopropylamine,butylamine,octylamine and dodecylamine,which was used as hydrophobic reagent.Taken the synthesis of N-dodecylamide CMS(ACMS-C₁₂)for example,the effects of some reaction factors on DS and reaction efficiency(RE)were investigated.The reaction consisted of two steps,CMS ammonium was first obtained which can be synthesized by one-step and two step reaction and then ACMS was obtained by amidation.The optimal reaction conditions of ammonization were as follows:two-step reaction method was applied,the acidity of CMS was 0.99,solvent is 50mL 50%ethanol aqueous,reaction temperature was 60℃,reaction time was 1.5 h,the reaction efficiency was 90%.The optimal reaction conditions of amidation were:145℃,7 hours reflux in o-xylene,the reaction efficiency was 91.7%.Similarly,a series of N-isopropylamide CMS(ACMS-C₃),N-butylamide CMS(ACMS-C₄),N-octylamide CMS(ACMS-C₈)and ACMS-C₁₂with different DS_FAwere obtained.Viscosity behaivor,surface properties and emulsification properties of the products were investigated.The emulsification mechanism of ACMS used in liquid paraffin emulsification were discussed.The influence of DS_FA,DS_CM,pH,temperature,concentration of product,salt content and storage time were investigated,and emulsifying capacity of ACMS was compared with that of NP-10 and Tween-20.