Antimicrobial silver nanoparticle-doped poly(vinyl alcohol)/guar gum/gum ghatti nanocomposites: a multifaceted step towards sustainable packaging

Abstract

The present study describes the green synthesis of silver nanoparticles (AgNPs) using a fixed concentration of poly(vinyl alcohol) (PVA)/guar gum (GG)/gum ghatti (GGh) blend solution with different concentrations of AgNO₃ solution at room temperature and fabrication of PVA/GG/GGh/AgNP nanocomposites (PGGA) using a simple solvent casting method. The effect of the inclusion of AgNPs on the surface morphology, mechanical and thermal properties of the obtained PGGA nanocomposites was studied using Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, a Universal Testing Machine (UTM), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC), respectively. Also, the results were compared with the blend film PVA/GG/GGh (PGGA-0) without AgNPs. The X-ray diffraction (XRD) study confirmed the formation of AgNPs (17–40 nm), and SEM analysis suggested homogeneous distribution of AgNPs in the polymer matrix. The presence of AgNPs does not change the position of IR peaks in PGGA nanocomposites. There was improvement in the hydrophobicity (63.6 ± 3.3° to 96.3 ± 2.5°) and thermal stability of PGGA nanocomposites compared to the PGGA-0 blend film. Further analysis of the results suggested an increase in the elongation at break of PGGA-4 nanocomposites with an increase in the concentration of AgNPs (0.2% w/v). Moisture adsorption was significantly decreased by the addition of AgNPs into the polymer matrix compared to the PGGA-0 blend film. The increase in AgNP content effectively inhibited the growth of bacteria. The soil burial test indicated biodegradation of the PGGA nanocomposites. Application studies on fresh coriander leaves confirmed that PGGA-1 films effectively enhanced shelf life and quality retention under ambient conditions. Improved moisture control, chlorophyll preservation, and sensory attributes highlight their practical potential in sustainable food packaging.