Evaluation of various organosilanes in the functionalization and dispersibility efficiency of reduced graphene oxide in epoxy

Abstract Graphene has attracted increasing attention due to its unique properties and widespread applications in various sectors, including its use as a nanofiller in polymer matrices. However, its poor dispersion within the matrix compromises the desired nanocomposite properties, making chemical functionalization a viable strategy to enhance its applicability. This study evaluates the dispersion of reduced graphene oxide (rGO) functionalized with different organosilanes in an epoxy matrix. Initially, graphene oxide (GO) was synthesized and functionalized with 3-aminopropyltriethoxysilane (APTES), 3-aminopropyltrimethoxysilane (APTMS), 3-glycidoxypropyltrimethoxysilane (GPTMS), and triethoxymethylsilane (MTES), followed by thermal reduction to obtain the corresponding functionalized rGO. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), dispersion stability in solvent, and scanning electron microscopy (SEM) were used to confirm functionalization and assess its efficiency. The results demonstrated successful covalent functionalization with all silanes, ensuring the permanence of their molecules on the rGO basal plane. Subsequently, nanocomposites were prepared with 0.5 wt.% of each functionalized rGO to evaluate their dispersion within the polymer matrix. SEM analysis of fracture surfaces revealed that nanocomposites containing functionalized rGO exhibited improved distribution, dispersion, and interfacial bonding compared to those with non-functionalized rGO. Among the tested organosilanes, rGO functionalized with APTES presented the most satisfactory results. Graphical abstract