Effect of hydroxyapatite on physical, mechanical, and morphological properties of starch-based bio-nanocomposite films

In this research, nanocomposite films based on starch were developed with the addition of hydroxyapatite nanoparticles as a mineral filler. Hydroxyapatite was synthesized by a chemical method using calcium nitrate and diammonium hydrogen phosphate. Various concentrations of hydroxyapatite nanoparticles were mixed with starch, and the developed films were evaluated in terms of physical, mechanical, and morphological properties. The highest values of mechanical parameters (tensile strength and elongation at break) were determined for the starch/hydroxyapatite film at 15 wt.% hydroxyapatite nanoparticles concentration (3.03 MPa, 37.41%, respectively). As hydroxyapatite concentration was increased from 0 to 20 wt.%, the solubility in water of the films decreased, whereas the solubility in acid increased. The crystalline structure of hydroxyapatite decreased the transparency of film and increased transparency value. Thus, a biodegradable film could be obtained with the addition of hydroxyapatite as a reinforcement filler up to 15 wt.%. It could be developed as a sustainable alternative for packaging industry.