Performance improvement of starch films reinforced with starch nanocrystals (SNCs) modified by cross‐linking

Starch nanocrystals (SNCs) obtained from acid hydrolysis of waxy corn starch were modified by cross‐linking using either sodium hexametaphosphate or glutaraldehyde in water. The cross‐linking preserved the crystalline structure of SNCs and improved the dispersion of SNCs in water. Thermoplastic starch (TPS) nanocomposite films reinforced with SNCs or the cross‐linked SNCs were prepared by casting and evaporation. Compared with the SNCs/TPS film, the tensile strength and elongation at break of the cross‐linked SNC‐reinforced TPS films were increased and the Young's modulus was remained almost unchanged. Moreover, the moisture barrier was enhanced for TPS nanocomposite films reinforced with cross‐linked SNCs. The performance improvement of the cross‐linked SNC‐reinforced TPS nanocomposite films was attributed to better dispersion of the cross‐linked SNCs in TPS matrix and different reinforcement/matrix interactions.