Studies On Sizing Behavior Of Amphoteric Starch Sizes

Amphoteric starch with quaternary ammonium and carboxylic groups was prepared by reacting N-(3-chloro-2-hydroxyproply) trimethylammonium and monochloroacetic acid to cornstarch for overcoming the defeats of the quaternary ammonium cationic starch and carboxylic anionic starch,and expanding their applications for textile sizing materials.The paper investigated the influence of modification extent of the amphoteric starch on paste abilities,film behaviors, adhesions to fibers and anti-flocculation with anionic ingredients.The effects of the starch-PVA blends on the adhesion to polyester/cotton fibers were estimated.It was found that the etherified extent has a much notable effect on the paste viscosity,film behaviors and adhesion.The higher the DS value,the higher the viscosity.The elongation and flexibility of the film ascended with the rise of both DS_c and DS_a.The adhesion enhanced with the DS_a grew.And introducing the cationic and anionic groups simultaneously onto starch eliminated the flocculation of cationic starch with anionic ingredients if the mole ratio of the cationic groups to anionic ones was＜4:1.The amphoteric starch benefited the reduction of the PVA amount,protected the environment and decreased the productive costs.The effects of the etherified starches containing carboxymethylated and/or cationic groups on the adhesion to wool fibers were researched by a slightly sizing roving method. The maximum strength,work to break,and breaking elongation of the roving were used to quantitatively characterize the adhesion indexes.The results manifested that three kinds of modification enhanced the adhesion of starch to wool fibers,and the adhesion increased with the modification extent increased.The carboxymethylated and cationic multi-modification of starch was the most effective one among three kinds of etherified starches for increasing the adhesion of starch to wool fibers.