Effect of Graphene Oxide Addition on Lightcured Nanocomposite Properties

Objectives: Graphene oxide (GO) is graphene derivative which has exceptional mechanical properties, antimicrobial effect, and good biocompatibility. This study was conducted to find out its effect on nanocomposite hardness, flexural strength, microstructure, antimicrobial properties, and electric conductivity.
Methods: GO was synthesized from graphite using Modified-Hummers method then mixed with monomer matrix (UDMA:TEGDMA:DMA-EMA:HEMA=17:5:5:10), zirconia, and chitosan; and was photo-polymerized. Mechanical properties were tested on Vicker’s Hardness and Universal Testing Machine. Microstructure was observed using Scanning Electron Microscope (SEM). Antimicrobial properties towards Streptococcus mutanswas tested using well diffusion method. Electric conductivity was tested using digital multimeter. The obtained datasets were tested using one-way ANOVA, except for hardness which was tested using Kruskal-Wallis method (p<0.05).
Results: Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) showed that GO has been successfully synthesized. The highest hardness was found in sample with 0.25wt%GO. The highest flexural strength was found in sample with 0.10wt%GO. In SEM result, GO formed netlike structure which distributed load evenly. Sample had the highest bacteriostatic properties towards Streptococcus mutansin 0.75wt%GO. Electric conductivity test result showed all samples as isolators.
Conclusions: Addition of GO into lightcured nanocomposite can increase hardness, flexural strength, and antimicrobial properties in certain percentages.