Synthesis and characterization of thermoplastic starch/PVA/cardanol oil composites loaded with in-situ silver nanoparticles

Abstract

A novel nanocomposite films of native and modified starch/polyvinyl alcohol (PVA)/sorbitol/cardanol oil with in situ synthesis of silver nanoparticles were prepared. The surface morphology of modified starch was found to be more homogenous than native starch with a good distribution of silver nanoparticles. This result indicated to boost in plasticization after starch modification as observed by scanning electron microscope. Transmission electron microscope confirms the formation of silver nanoparticles with diameters ranging from 50 to 80 nm with homogenously distributed. Moreover, modified starch showed lower water vapor permeability compared to unmodified starch at 39%. The addition of cardanol oil at 0.2% showed significant increases in the elongation of modified starch films by 280.9% compared to the unmodified starch films. However, the film elongation was increased by 421.7% with 2 mmol silver nanoparticles and 0.2% cardanol oil, while it decreased by 14.2 in the modified starch film. Also, cardanol oil reduces transmittance in the UV region for native and modified starch films by 56.2% and 56.5%, respectively. The nanocomposite films demonstrated good antimicrobial activity against gram-positive and gram-negative bacteria and yeast. These films can be a potential candidate for application such as food packaging materials.