Effect of functionalized graphene addition on mechanical and thermal properties of high density polyethylene

High density polyethylene (HDPE)/graphene nanocomposites were successfully synthesized by compounding of HDPE, as polymer matrix, with hexamethylenediamine functionalized graphene. The resulting nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and thermal gravimetric analysis (TGA) techniques. SEM characterization confirmed the good dispersion (homogeneous and uniform) of graphene in the polyethylene matrix. The TGA technique revealed a slight improvement in thermal resistance. Functionalized graphene improved a better thermal stability of HDPE (up to 6 C) than non-functionalized graphene (up to 2 C). Mechanical tensile and torsion tests showed that HDPE/functionalized graphene nanocomposites exhibit high tensile strength and low torsional strength compared to HDPE/non-functionalized graphene nanocomposites. Compared to pure HDPE, the Young's modulus increased by 80% and 30%, whereas, the torsion modulus increased by about 34% and 44% for the HDPE/functionalized and HDPE/non-functionalized graphene, respectively. Regardless of this increase, it can be seen that the torsion modulus of HDPE/non-functionalized graphene is much higher than that of HDPE/functionalized graphene.