Modification and development of high bioactivities and environmentally safe polymer nanocomposites doped by Ni/ZnO nanohybrid for food packaging applications

Abstract

This study aimed to develop a sodium alginate (50%NaAlg)/polyethylene oxide (50%PEO) blend-based film loaded with nickel and zinc oxide nanoparticles (Ni/ZnO NPs) as a reinforcing and antibacterial agent. The Ni/ZnO NPs as nanohybrid were synthesized via the sol–gel method at different concentrations (0.0, 5.0, 10.0, 15.0, 20.0 wt.%). The solution cast approach was utilized to create polymer nanocomposites samples from NaAlg/PEO/Ni/ZnO NPs for application in bioactive food packaging. The films were characterized using various procedures in detail. With the addition of Ni/ZnO, the XRD confirms the expansion of amorphous nature within NaAlg/PEO. The crystallinity degree of NaAlg/PEO-Ni/ZnO nanocomposite were decreased from 47 to 25%. The interactions between the components of NaAlg/PEO and Ni/ZnO NPs are revealed by FTIR findings. The bio-degradable nanocomposites' dielectric behavior, electrical conductivity as well as mechanical properties, were investigated. With the addition of Ni/ZnO NPs, the dielectric and AC conductivity properties of the nanocomposites improved with the increase in the concentrations of Ni/ZnO NPs. The loading of Ni/ZnO nanoparticles increased the mechanical characteristics of the nanocomposite, such as tensile strength increased from 30.18 to 72.34, stiffness increased from 18.78 to 38.42, and Young's Modulus increased from 8.24 to 29.76. The antibacterial activity of nanocomposites films was examined against Gram-negative (Escherichia coli), Gram-positive (Staphylococcus aureus), Aspergillus niger (fungus) and Candida albicans (yeast). Though the tested NaAlg/PEO blend did not indicate any activity against the microbial strains, when Ni/ZnO NPs were added, activity against E. coli, S. aureus, fungus and yeast was enhanced. The water solubility of nanocomposites films reduced from 65.5% to 9.81% with increasing of Ni/ZnO NPs content. The present study shown that NaAlg/PEO-Ni/ZnO films were more effective in inhibiting bacteria growth than pure NaAlg/PEO film, confirming the nanocomposites film's potential application as antimicrobial food packaging.

Keywords

• Ni/ZnO NPs
• NaAlg/PEO
• XRD
• Mechanical properties
• Dielectric parameters
• Antimicrobial activity