Effect of silicon dioxide nanoparticle on microstructure, mechanical and barrier properties of biodegradable PBAT/PBS food packaging

Biodegradable polyester polymers including poly(butylene adipate-co-terephthalate) (PBAT) and poly(butylene succinate) (PBS) are used as sustainable and eco-friendly food packaging but poor water vapor barrier properties limit their applications with moisture-sensitive products. This research blended PBAT/PBS materials at 60/40 and 50/50 with silicon dioxide (SiO2) nanoparticles as master batch pellets via twin-screw extrusion before sheet-casting to improve food packaging barrier properties. PBAT/PBS/SiO2 nanocomposite films were investigated by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy and also for mechanical relaxation, microstructure, surface topography, and barrier properties. Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) indicated dispersed SiO2 nanoparticle aggregation in polymer matrices at higher loading. FTIR spectroscopy results suggested modified CO stretching vibrations in polyesters, concurrent with shifting X-ray diffraction angles depending on nanoparticle content and polymer blend ratios. Adding SiO2 nanoparticles at up to 1% exponentially reduced water vapor permeability by up to 26%, while decreasing oxygen permeability (up to 8%). Mechanical properties reduced when adding SiO2 nanoparticles but film stretching improved polymer orientation at higher loading, thereby increasing tensile strength and elongation. Compounding SiO2 nanoparticles with PBAT/PBS polyester polymer blends enhanced barrier properties for biodegradable food packaging.