Starch Maleation and Sulfosuccinylation to Alleviate the Intrinsic Drawback of Brittleness of Cornstarch Film for Warp Sizing

The objective of this work was to examine the effects of starch maleation and sulfosuccinylation, respectively, on the properties of starch film for warp sizing. Acid-thinned cornstarch granules were succinylated with maleic anhydride and then sulfonated with sodium bisulfite to different degrees of substitution (DS). The effects of the maleation and sulfosuccinylation on the properties such as tensile strength, breaking elongation, work-to-break, flex-fold resistance, moisture regain, and water resistance of maleinated starch (MAS) and sulfosuccinylated starch (SSS) films were investigated. The films were cast from cooked starch aqueous paste under room temperature. The results showed that both the maleation and sulfosuccinylation significantly increased the breaking elongation, work-to-break, flex-fold resistance, and moisture regain of starch film, but decreased film strength to a limited extent. These two modifications were all able to toughen starch film and reduce its brittleness. Increasing the levels of starch maleation and sulfosuccinylation enhanced the toughness. Starch sulfosuccinylation was found to be preferred to the maleation in toughening starch film X-ray diffraction confirmed that SSS film was lower than MAS one in the degree of crystallinity, thereby displaying a stronger toughening effect. Low level of starch sulfosuccinylation could be adopted to reduce the brittleness of cornstarch film for warp sizing based on the results obtained in this work.