The synthesis and characterization of graphene oxide in polystyrene-ethylene-butylene-polystyrene

Abstract

The graphene based material called graphene oxide (GO) is receiving a great deal of attention due to its outstanding properties such as low electronic conduction, but good proton conductivity because of the presence of hydroxyl, carboxylic, and epoxy groups in the hydrophilic region of GO. Furthermore, the sp² carbon layer present in the hydrophobic region of GO can help to increase the mechanical strength of the membrane due to its strong covalent bonding. Fabrication of graphene based polymer composite has significantly shown the improvement of membrane properties. In this study, polystyrene-ethylene-butylene-polystyrene (PSEBS) was applied in the preparation of graphene oxide (GO) polymer nanocomposite. GO was synthesized from graphite powder using Hummer’s method. The dope solution of PSEBS-GO composite membrane was prepared by introducing GO solution with 7.5 wt. % PSEBS solution with ratio of 1:3. Characterization of GO and PSEBS-GO were studied by using attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM). The synthesized GO was also characterized using X-ray diffractometer (XRD). The GO structure was confirmed by using ATR-FTIR with the presence peaks at 3217.32, 1604.36, 1364.12, and 1050.06 cm^-1 assigned to O-H stretching vibrations of the C-OH groups and water, C=C stretching, C-OH stretching (in COOH), and C-O stretching respectively. The XRD analysis showed GO is successfully prepared from graphite due to the presence of intense peak at 2θ = 11.285°. From micrograph of SEM, the images of exfoliated GO have a bulky structure due to the defect of graphite layer when oxygen groups are introduced in the graphite layers, while PSEBS-GO having smaller pores compared to the PSEBS membrane. The percentage of water uptake of PSEBS and PSEBS-GO membrane were 29.07% and 38.26%, respectively.