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

Abstract

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.