Studies On Synthesis And Properties Of Cationic Starch Benzoate

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, the cationic starch was hydrophobically modified with benzoyl group which was selected as the hydrophobic group, and preparation and properties of cationic starch benzoate were studied.Cationic degradative starch benzoate with high degree of substitution(DS) was prepared by reaction of cationic degradative starch with benzoyl chloride(BC) which was used as hydrophobic reagent in the mixed solvent containing water and ethanol. The effects of some reaction factors on DS and reaction efficiency(RE),.such as amount of ethanol in the solvent, dosage of solvent, different alkali, dosage of alkali, reaction time, reaction temperature were investigated. The optimal reaction conditions are as follows: the cationic degradative starch(DS=0.68) is 4g, solvent is 20mL (water with 10% ethanol), the ratio of Na₂CO₃ to BC is 1:1, reaction temperature is 70℃, reaction time is 1 h.Cationic starch benzoate with high degree of substitution(DS) was prepared by reaction of cationic starch with BC which was used as hydrophobic reagent in the mixed solvent containing water and ethanol. The effects of some reaction factors on DS and RE, such as amount of ethanol in the solvent, dosage of solvent, different alkali, dosage of alkali, reaction time, reaction temperature were investigated. The optimal reaction conditions are as follow: the cationic starch(DS=0.47) is 5g, solvent is 70mL (water with 20% ethanol), the ratio of Na₂CO₃ to BC is 0.75:1, reaction temperature is 60℃, reaction time is 2 h.A series of cationic starch benzoate with different degradation and DS of cation and benzoyl group were prepared. Their flocculation of oil-in-water emulsion and waste water of disperse dyes was examined. The effects of some factors on flocculation of oil-in-water emulsion and waste water of disperse dyes, such as introduction of benzoyl group, different DS of cation and benzoyl group, different degradation were investigated.