Quaternization/maleation of cornstarch to improve its adhesion and film properties for warp sizing

The aims of this work were to examine the influences of starch quaternization/maleation on the film properties and adhesion-to-fibers of starch, and also to reveal if the quaternization/maleation could improve the adhesion-to-fibers and film properties of starch. A series of quaternized and maleated cornstarch (QMS) with the total degree of substitution (DS) values of 0.02-0.061 were prepared via a quaternization of acid-thinned cornstarch with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride for introducing 3-(trimethylammonium chloride)-2-hydroxypropyl (TACHP) substituents onto the backbones of starch, and a further maleation with maleic anhydride for the introduction of maleate substituents. The effects of starch quaternization/maleation on paste viscosity, paste stability, adhesion strengths to both cotton and viscose fibers, and film properties of starch were investigated. The degree of crystallinity of starch film was quantitatively obtained from X-ray diffraction analysis. It was found that the quaternization/maleation was able to stabilize the viscosity, increase adhesion strengths of starch to both cotton and viscose fibers, enhance breaking elongation, moisture regain, and bending endurance of starch film, and decrease tensile strength and degree of crystallinity of starch film, thereby improving the adhesion and displaying toughening effect to the film. Increasing the level of starch quaternization/maleation was capable of gradually increasing adhesion and toughness of the film. The quaternization/maleation with the DS values of 0.04-0.061 could be applied for the alleviation of the intrinsic drawbacks (insufficient adhesion and film brittleness) of cornstarch for warp sizing.