Effect of Amylose-Amylopectin Ratios on Physical, Mechanical, and Thermal Properties of Starch-Based Bionanocomposite Films Incorporated with CMC and Nanoclay

The objective of this work is to examine the effect of amylose-amylopectin ratios on physical, mechanical, and thermal properties of starch-based bionanocomposite films. Starch sources with different amylose-amylopectin ratios (potato starch, 20:80; wheat starch, 25:75; corn starch, 28:72; and high-amylose corn starch, 70:30) are blended with carboxyl methylcellulose (CMC) and sodium montmorillonite (Na-MMT) to produce bionanocomposite films. Experimental results reveal that corn starch/CMC/nanoclay bionanocomposite films possess higher tensile strength, lower film solubility, lower water vapor permeability, and higher glass transition temperature due to molecular structure of amylose-amylopectin and their molecular space in corn starch, which help in strong interaction with CMC and extensive intercalation of nanoclay. The highest degree of crystallinity and strong interaction of corn starch with CMC (OH andCOOH) and nanoclay (SiOSi and AlOH) are confirmed by X-ray diffractometer (XRD) and Fourier transform infrared (FTIR) spectroscopy results, respectively. The prepared bionanocomposite films can be used for food packaging applications to improve the shelf-life and safety of food products, which can serve as a potential substitute for conventional plastic packaging materials.