Green fabrication of PVA based biofilms incorporated with shrimp shell derived chitosan, plasticized with PEG or Gly and reinforced by biosynthesized ZnO nanoparticles

This study reports the development of eco-friendly nanocomposite biofilms (NCBFs) based on Polyvinyl alcohol (PVA) and chitosan extracted from shrimp shells (SSDCs), reinforced with biosynthesized zinc oxide nanoparticles (BioZnO NPs) derived from Avicennia marina leaf extract. Polyethylene glycol (PEG) and glycerol (Gly) were incorporated as plasticizers to enhance film flexibility and processability. The resulting NCBFs were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), tensile testing, migration stability analysis, and water vapor permeability measurements. XRD analysis confirmed the high-purity crystalline phase of BioZnO NPs and revealed characteristic diffraction peaks corresponding to both BioZnO NPs and SSDCs within the NCBF matrices, thereby validating successful composite formation. Incorporation of BioZnO NPs at an optimum concentration significantly enhanced tensile strength (59.91 MPa), elongation at break (93.56%), and elastic modulus (66.76 MPa), while simultaneously reducing water vapor transmission (0.48 × 10^-6 g.m/m².h.pa) and polymer migration. In contrast, films prepared without BioZnO NPs exhibited reduced tensile strength (39.85 MPa) and flexibility, alongside a substantially increased elastic modulus (507 MPa), highlighting the reinforcing role of the nanoparticles. Furthermore, variations in SSDCs content influenced film flexibility, with lower SSDCs concentrations yielding more flexible films. Overall, the optimized NCBFs demonstrated superior mechanical and barrier properties, indicating strong potential for sustainable packaging applications. The use of natural polymers and BioZnO NPs offers a cost-effective and environmentally benign alternative to conventional petroleum-based plastics, contributing to the mitigation of plastic pollution.