Potential perspectives on the use of poly (vinyl alcohol)/graphene oxide nanocomposite films and its characterization

The aim of this work was to investigate the effect of graphene oxide (GO) nanoparticles on the physicochemical, mechanical, thermal, and biodegradation properties of Polyvinyl alcohol (PVA) films. PVA-based nanocomposite (NC) films were fabricated using solution casting technique by adding a low concentration of GO from 0.1 to 0.7%. The tensile strength of the NC films was increased by the addition of GO from 1.40 +/- 0.02 MPa to 1.99 +/- 0.02 MPa. However, the elongation at break of the NC film was enhanced from 201.02 +/- 5.10 to 268.64 +/- 5.83% at 0.1-0.3% concentration of GO, and it was decreased with further addition of GO. A considerable improvement in the water vapor permeability was observed at 0.3-0.5% GO, with a value of 6.76 +/- 0.06 x 10- 5 to 6.69 +/- 0.08 x 10- 5 (g/m.hr. Pa) with respect to neat PVA 8.16 +/- 0.08 x 10- 5 (g/m.hr. Pa). Additionally, the use of GO also led to an enhancement in moisture retention capacity, with values ranging from 80.08 to 82.06%. Differential scanning calorimetry (DSC) result revealed a rise in glass transition temperature i.e. 95.62 degrees C, and maximum enthalpy 50.28 (J/g) at 0.3% GO. Moreover, thermogravimetric analysis (TGA) studies also showed less mass degradation for Poly (vinyl alcohol)/graphene oxide (PVA/GO) films at higher temperatures compared to PVA film. From scanning electron microscope (SEM) micrographs, minimum surface defects, homogenized mixing, and less agglomeration in the PVA/GO film was observed. This observation was further supported by Fourier-transform infrared spectroscopy (FTIR) data, which indicated a strong hydrogen bonding between the functional groups of GO and PVA polymer chains. Furthermore, the NC films exhibited an effective antibacterial activity against Staphylococcus aureus (gram-positive bacteria). Adversely, there was no inhibition zone observed in neat PVA and its NC films against Escherichia coli (gram-negative bacteria). The incorporation of GO nanofillers was found to reduce the rate of biodegradation of the NC films, as determined in soil burial study. However, improved microorganism degradation was observed in both Bacillus subtilis and Pseudomonas putida bacteria strains. Overall, the acquired results validate the use of GO as an excellent option for the fabrication of biodegradable nanocomposite films that may be used for packaging applications.