Cross-linking/sulfonation to improve paste stability, adhesion and film properties of corn starch for warp sizing

Abstract

To investigate the influence of cross-linking/sulfonation on the viscosity stability, adhesion, film properties and desizability of corn starch for ameliorating its end-use ability in application of warp sizing, a series of itaconic acid cross-linked and sulfonated starch (IACLSS) samples with different levels of cross-linking (LCL) and degrees of substitution (DS) were synthesized by the cross-linking of acid-converted starch (ACS) with itaconic acid (IA) and subsequent sulfonation with NaHSO3. The apparent viscosity and viscosity stability were determined and adhesion was evaluated using a standardized method (FZ/T 15,001–2008). Film properties were also estimated in terms of tensile strength, breaking elongation, bending endurance, and moisture regain and the desizability of the IACLSS samples was investigated by measuring the time required to break the films in hot water. The experimental results showed that cross-linking/sulfonation was capable of improving the viscosity stability of cooked starch paste, enhancing the adhesion of starch to cotton and polyester fibers, increasing breaking elongation, bending endurance and moisture regain of starch film as well as decreasing its tensile strength, thereby stabilizing paste viscosity, ameliorating the adhesion to fibers and diminishing film brittleness. In addition, modification could reduce the time required to break the films in 80 °C water, indicating that modification favored the desizing of starch in hot water. Increasing sulfonation levels whilst decreasing the LCL values favored improvement in stability and desizability, enhancement in the adhesion to cotton and polyester fibers, and decrease in brittleness. The IACLSS showed potential in the applications of cotton and polyester sizing.