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.

Chemically modified waxy corn starch is a promising material for biodegradable bioplastic synthesis. This work is to study the film performance and microbial enzymatic biodegradation of the film made from chemically modified waxy corn starch according to the effect of pre-gelatinization and cardanol oil with various ratios as a mixed plasticizer with sorbitol. The preparation of biodegradable bioplastic films from waxy maize acetylated di-starch adipate (WADA) and waxy maize pregelatinized acetylated di-starch adipate (PWADA) blended with polyvinyl alcohol polymer using sorbitol and cardanol oil mixture as plasticizers were performed. Characterization of biodegradability by enzymes mixture of (alpha-amylase and glucoamylase) and soil burial test. The weight loss reached 96% and the degradation percentage reached 95.5% of PWADA and these results were significantly (p < 0.05) lower than WADA; as proved by high-performance liquid chromatography, increasing osmolality is evidence of the degradation as measured by the osmometer and the physical appearance of the film indicated complete degradation after 21 days. The film morphology, chemical structure, crystallinity, transparency, and thermal stability were studied using a scanning electron microscope, Fourier-transformed infrared, X-ray diffraction, UV–Vis spectrophotometer, and thermal gravimetric analysis. As a result, under the electron microscope, PWADA films had a more homogenous surface. The films’ infra-red spectra showed similar patterns, indicating identical chemical structures. Waxy maize starch has an A-type crystalline structure and after the thermoplasticization, the X-ray diffractogram showed new peaks appeared at 2θ of 13.2°, 19.5°, and 20.8°, which attributed to a V-type crystal pattern. The addition of cardanol oil restricts the transmission of light in the UV region by 250 nm by 69 and 63.4%, respectively, indicating UV absorber films. Furthermore, adding oil to (PWADA) and (WADA) films increased onset deterioration from 272 to 318 °C and from 317 to 320 °C, indicating that their thermal stability is improved. The water uptake rate and water vapor permeability increase after the pre-gelatinization of WADA films without cardanol but slightly decrease after the addition of cardanol oil. Also, pre-gelatinization decreases the elongation by 33.3% while increasing the strength by 10.5% of the films. Hence, waxy-modified maize starch film has the potential to be a biodegradable, thermal stable, and UV absorber film in packaging material.