This study considered the effect of amylose content (30% and 70%), montmorillonite (MMT) fraction (5 and 15%) and preparation method on mechanical and barrier properties of starch/clay nanocomposites prepared by casting. In Method 1, (30% w/w) glycerol was incorporated before starch gelatinization and MMT addition, while in Method 2 after gelatinization and MMT addition. Nanocomposites with higher amount of MMT showed the highest tensile strength and Young's modulus for both preparation methods. Method 1 favored nanocomposite properties of films with less amylose content, meanwhile Method 2 favored nanocomposites properties with higher amylose content. Water vapor permeability did not decrease significantly in starch films with different amylose content with the two different preparation methods. X-ray diffraction of the starch films indicated intercalated structures. Higher melting temperature (Tm) was found for nanocomposites with Method 2, indicating more ordered structures. Films with 70% amylose content have higher Tm than films with 30% amylose.
Keywords: Barrier; Films; Mechanical properties; Starch–clay composite.
Copyright © 2015 Elsevier Ltd. All rights reserved.