Effect of Graphene Oxide Nanoparticles on the Physical and Mechanical Properties of Chitosan/Gelatin/Polyvinyl Alcohol Films

 Graphene oxide (GO) as an important nanoparticle having unique characteristics and the ability to improve physical and mechanical properties of different biopolymers has been taken into consideration during the last decade.  Thus, in this study, graphene oxide was used for the modification of polymeric films based on chitosan (CS)/gelatin (GL)/polyvinyl alcohol (PVA).

Two series of films with different composition ratios were prepared by solution casting method. Graphene oxide at different concentrations (0, 0.2, 0.4 and 0.8 wt%) was added to the solutions to investigate the effect of PVA and GO amounts on the physical and mechanical properties of the films. The synthesized films were investigated by tensile, swelling, water vapor transmission rate (WVTR), antibacterial and scanning electron microscopy (SEM) tests.

The tensile results showed that the graphene oxide improved the mechanical properties such as tensile modulus and strength, while decreased the elongation-at-break of the prepared samples. The increase in the PVA content of the films led to lower mechanical properties in films. The results of swelling tests at three different (neutral, acidic, and basic) media showed that the PVA led to the decrement of swelling, and higher amounts of GO resulted in a considerable decrease in degree of swelling of the films. The WVTR results showed that the changing in film composition did not considerably change the WVTR of the films, while the GO resulted in a decrease in WVTR of the samples. The antibacterial results showed that adding PVA did not affect the inhibition zone diameter, meanwhile the addition of graphene oxide led to an increase of the inhibition zone diameter. The SEM results showed a uniform distribution of GO nanoparticles within the polymeric films which was due to the compatibility of GO with polymeric matrix.