The effect of thermal annealing of GO/PVA on their physical, structural, and morphological properties.

In this research the synthesis of graphene oxide (GO) through the Hummers method, to obtain various percentage nanocomposite materials incorporating GO into polyvinyl alcohol (PVA) (2%GO/PVA, 3%GO/PVA, and 20%GO/PVA), and the detailed investigation of these composites’ morphological, structural, and optical characteristics using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Raman spectroscopy, and Scanning electron microscopy (SEM). The main goal of the presented work is to investigate how the physical properties change in the wide-range concentrations of the GO/PVA composite materials, as well as at different thermal annealing temperatures. From the XRD results, the space between the sheets is decreased by increasing the thermal annealing temperature. By the Halder-Wagner method, crystallite size and microstrain of the various percentages of GO/PVA were determined. The high microstrain and crystallite size belong to thermal annealed at 70°C of 3% GO/PVA (D = 8.50 nm/ε = 11%) and thermal annealed at 40°C of 20% GO/PVA (D = 13.70 nm/ε = 16 %). At room temperature and the highest annealing temperature, the microstrain value is minimal or equal to 0, because, its crystal structure is stable at low temperatures and it occurs as a result of relaxation due to rearrangement of the polymer chain at high temperatures. From Raman measurements, the ID/IG ratio for 2% and 3% GO/PVA composite materials increased with increasing temperature compared to the pristine GO. This indicates that the defect in the structure increases due to temperature. [ABSTRACT FROM AUTHOR]