| In this study, nanocomposite films with enhanced functional properties were prepared by loading titanium dioxide (TiO2) and/or zinc oxide (ZnO) nanoparticles within 4A zeolite (4AZ) particles, and then incorporating
these nanocomposites into a poly (vinyl alcohol) (PVA) and gelatin matrix. The composition and morphology of
the films were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier
transform infrared (FTIR), and X-ray diffraction (XRD). The thermal behavior of the films was established using
thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). SEM showed the nanoparticles
were dispersed throughout the films when used at these levels. FTIR indicated that the inorganic nanoparticles
interacted with the PVA/gelatin polymer network through hydrogen bonding. XRD confirmed that the nanoparticles were in a crystalline state within the films. DSC and TGA showed that introduction of the nanoparticles
modified the nanocomposite’s thermal behavior. Nanoparticle addition had a number of effects: (i) it decreased
film transparency from 78.7% to 69.4% 72.0% and 69.7%; (ii) it decreased film water vapor permeability (WVP)
from 8.20 × 10− 9 to 5.13 × 10− 9, 5.71 × 10− 9 and 5.24 × 10− 9 g/Pa.h.m; (iii) it reduced film oxygen
permeability from 4.57 to 3.29, 3.10 and 3.00 mEq/g; and (i) it increased film tensile strength (TS) from 14.6 to
22.0, 20.3 and 18.0 MPa, for PVA/gelatin films containing 0%, 1.5% ZnO, 1.5% TiO2 and 1% (ZnO + TiO2)
nanoparticles, respectively (with the nanoparticles being trapped within 4AZ). Moreover, active nanocomposite
films exhibited significant antimicrobial effects especially against gram-negative bacteria. Overall, our results
show that nanoparticle-loaded PVA/gelatin nanocomposites may be useful as active biodegradable nanocomposite films for application in the packaging industry and that their properties can be modulated by controlling the nature and level of nanoparticles incorporated. |