Synthesis And Application Properties Of Anion Starch

Anion starch is a kind of fine chemicals with broad research and application prospect. Anion starch can be prepared by introduction of anion functional groups, such as carboxyl and sulfate groups, into the starch molecule by etherification or esterification. The anion groups can provide starch with the properties of cold water dissolution and high viscosity. The main method for the preparation of anion starch is solvent method. This method needs solvent and catalyst, which not only increases the cost, but also causes serious environment problem. In this paper the starch maleate with high degree of substitution (DS) and high viscosity was prepared by dry method.With the pretreatment of cross-linking and alkalinization, starch was reacted with maleic anhydride in a vacuum oven. The factors that could affect the DS and viscosity of starch maleate were investigated in detail, and the optimal reaction conditions were got. Starch maleate with DS of 0.59 and viscosity of 28000mPa·S was obtained under optimal conditions. A degradative starch maleate wirh DS of 0.58 was used as water-reducing agent on cement with fluidity of 214mm, and the dispersing performance of MS was better than the traditional naphthalene sulfonated formaldehyde condensates (FDN).The carboxymethyl starch is an important kind of anion starch, but limitations such as low shear resistance and salty resistance limit its use. The sulfate group was introduced into the molecule of carboxymethyl starch for the increase of the salty resistance. The result of the viscosity performance was well improved by the sulfate group. Sulfonic-carboxymethyl starch with DSs of 0.27 was prepared by carboxymethyl starch with DSc of 0.74 with the optimal reaction conditions. The viscosity of sulfonic-carboxymethyl starch solution was 16000mPa·S with the concentration of 1.0%. The sulfonic-carboxymethyl starch was used as printing paste. The rate of paste removal, the color yield and permeability were well improved compared with that of carboxymethyl starch and sodium alginate.