Effect of functionalized graphene/CNT ratio on the synergetic enhancement of mechanical and thermal properties of epoxy hybrid composite

Abstract

Hybrid fillers comprise of amine functionalized multilayer graphene (Af-MLG), amine functionalized MWCNT (Af-MWCNT) were prepared and their synergetic effects with regards of enhancing the mechanical and thermal properties of epoxy composites were investigated. The samples were fabricated by keeping the ratio of Af-MLG and Af-MWCNT nanofillers as 1:1, 1:3 and 3:1. The above-mentioned filler ratios were then mixed with an epoxy matrix by using probe sonication method. X-ray diffraction (XRD) was performed for phase identification exists in nanofillers due to surface functionalization while Fourier-transform infrared spectroscopy (FTIR) was performed to obtain an infrared spectrum in nanofillers, which confirms the presence of amine group. Transmission electron microscope (TEM) used for the confirmation of uniform dispersion of nanofillers in an epoxy matrix and scanning electron microscope (SEM) was used for the study of the morphology of fractured samples occurred during the tensile test of different wt% nanofillers reinforced composites. The results indicate that the tensile strength of the hybrid composite increased by 57.1 and 50.2% for the nanocomposites with 1:3 and 3:1 respectively when compared with neat epoxy composite. Moreover, flexural modulus and strength increase by 20 and 72% respectively for the sample with filler ratio 1:3 and 3:1. In order to examine the thermal decomposition, the thermogravimetric analysis (TGA) was performed in three different stages from 300 to 700 °C with a constant increment of 100 °C. A maximum gain of 20% was noticed for the samples with filler ratio 3:1 when compared with pristine epoxy nanocomposites. Henceforth, such hybrid nanocomposites with improved thermomechanical properties showed new pathways to many advanced structural and temperature based applications.