Fabrication and comprehensive characterization of HPMC/PVA/CMC-MoO₃ bio-nanocomposites: Enhanced mechanical, electrical, and antibacterial properties for food packaging applications

This study explores the synthesis and characterization of bio-nanocomposite films composed of HPMC/PVA/CMC blends with molybdenum trioxide (MoO₃) nanofillers at varying concentrations. X-ray diffraction (XRD) analysis confirms the structural integrity of the polymer matrix, with MoO₃ enhancing crystallinity as its concentration increases. Fourier-transform infrared spectroscopy (FTIR) reveals strong hydrogen bonding between MoO₃ and the polymer matrix, leading to improved interfacial compatibility. Ultraviolet-Visible (UV-Vis) spectroscopy indicates enhanced optical properties, with increased UV absorption correlating with higher MoO₃ content. As the MoO₃ concentration increased, the indirect energy gap decreased from 3.96 eV to 2.94 eV. Mechanical testing demonstrates significant improvements in tensile properties, including Young's modulus, ultimate tensile strength, and toughness, attributed to MoO₃'s electrostatic and hydrogen bonding effects on the polymer network. Electrical and dielectric analyses further show that higher MoO₃ levels boost conductivity, interfacial polarization, and charge storage, particularly at low frequencies. Additionally, the addition of MoO₃ reduces the contact angle, enhancing hydrophilicity, and significantly increases cell viability, achieving a peak value of 93.33 ± 1.73 % at 2.0 % MoO₃ loading. Antibacterial assays confirm strong inhibition of both gram-positive and gram-negative bacterial growth, with greater efficacy observed against gram-positive strains. These results underscore the potential of HPMC/PVA/CMC-MoO₃ nanocomposites for applications in bio-compatible, mechanically robust, and antibacterial materials.