Effects of cationization of high amylose maize starch on the performance of starch/montmorillonite nano-biocomposites

In the present study, cationized high amylose maize starches (CS) with different degrees of substitution (DS) were prepared. The physical properties and microstructures of CS/montmorillonite (Mt and D1821Mt) films were investigated. Morphological analysis showed stronger intercalations of CS with hydrophilic montmorillonite (Mt) than with hydrophobic montmorillonite (D1821Mt). For CS/Mt nanocomposite films, an increasing exfoliation trend was detected with the increase in DS. On the whole, the tensile strength of CS/Mt nanocomposite films decreased while water vapor permeability increased with an increase of DS. The CS/Mt film with the DS of 0.04 showed the highest tensile strength (14.01 MPa) and lowest water vapor permeability (1.80 × 10−10 g m/m2 s Pa). Rheological measurements confirmed that the intermolecular forces between CS and Mt decreased with increasing DS. Mt could obviously increase the thermal stability of the films. Overall, CS with lower DS had better compatibility with Mt, which helped improve the properties of CS/Mt nanocomposite films.