Investigations on Thermomechanical and Biodegradable Properties of Alkaline Hydrolysis Isolated Nano Hydroxyapatite Reinforced Polylactic Acid Composite Blown Films for sustainable Packaging

In this study, nano-hydroxyapatite (n-HAp) was extracted from pink perch fish scales (PPFS) using a simple and efficient alkaline hydrolysis method. The obtained n-HAp was characterized through XRD, FTIR, Raman spectroscopy, TGA, SEM, and TEM. Various concentrations of n-HAp (0.25, 0.5, 0.75, and 1 wt.%) were then incorporated into a polylactic acid (PLA) matrix using solution blending followed by blown film extrusion. The influence of n-HAp on the thermal, mechanical, and biodegradable properties of the PLA-based composites was systematically analyzed. FTIR and Raman spectroscopy confirmed chemical bonding between n-HAp and the PLA matrix in the blown films. Thermal analysis via TGA revealed an increase in the initial degradation temperature compared to neat PLA, attributed to the presence of n-HAp. DSC analysis showed a reduction in glass transition temperature and crystallinity, which restricted polymer chain mobility and increased the amorphous phase. Mechanical property evaluation through tensile testing demonstrated that lower concentrations of n-HAp significantly enhanced elongation at break, with PLA_HAp 0.75 exhibiting improved flexibility and increase in elongation compared to neat PLA. A 180-day soil biodegradability study indicated that incorporating 0.5 wt.% n-HAp into the PLA matrix accelerated the hydrolysis process by 500%, enhancing the overall degradation of the PLA_HAp composite film. These findings highlight the potential of n-HAp in improving the functional properties of PLA-based composites for food packaging applications.