LAUSR

Abstract Few-layered graphene oxide (GO) nanosheets were obtained through the chemical reduction of the GO sheets via nature-based reagents, i.e., Tamarind (Tamarindus indiaca extract, TIE). The obtained rGO-TIE particles were then modified by zinc ions. The outcomes of the Raman spectroscopy, FT-IR, and X-ray diffraction analysis (XRD) revealed about 53% reduction in C O/C C ratio, 40% reduction in the 2ϴ corresponded to the (0 0 2) plane of GO, and a 60% increment of I2D/IG intensity (from Raman test results), indicating that the GO was successfully reduced and the interlayer d-spacing and the number of stacked layers decreased. The thermo-mechanical properties of the epoxy ester composite coatings containing 0.15 wt% of GO, rGO-TIE, and rGO-TIE-Zn particles were assessed by TGA-DTG, tensile, and DMTA analysis. From the DMTA outcomes, it was revealed that in the presence of rGO-TIE-Zn particles, the storage modulus (at 25 °C) and cross-linking density of the epoxy film were enhanced by 50% and 57%, respectively, compared to the unfilled coating. Tensile test results depicted about 58% and 41% degree of improvements in the energy at break and tensile strength of the epoxy film reinforced with rGO-TIE-Zn particles. FE-SEM analysis revealed that the better rGO-ESR-Zn(II) particles' dispersion/exfoliation level in the polymer matrix, as well as stronger polymer/particle interfacial bonding than GO, resulted in the higher thermo-mechanical properties. TGA results evidenced about 106 °C improvement in the T80% and 41% improvement in the thermal stability of the epoxy coating in the presence of rGO-ESE-Zn particles.