Epoxy/Functionalized MWCNT Nanocomposites: Cure Behaviour, Thermal Stability, Mechanical Properties and Fracture Morphology

Multi-walled carbon nanotubes were chemically functionalized with the aromatic amine functional groups. Two sets of epoxy/MWCNT nanocomposites were fabricated, each containing various amounts (0.1, 0.2, 0.3, 0.4 and 0.5 wt%) of unfunctionalized and functionalized MWCNTs respectively. The nanocomposites were subjected to TG-DTA, hardness and tensile tests in order to study the effect of functionalization of carbon nanotubes on thermal stability, cure behavior, hardness and tensile parameters of the samples. Tensile fracture morphology was also studied from SEM micrographs. The increasing effect of MWCNT and f-MWCNT on peak exothermic temperature of all the systems indicated the retarding effect of MWCNT imposed on the curing process of epoxy/hardener. However, the addition of nanotubes had a converse effect on the polymer network formation. No considerable effect on the thermal stability of any of the nanocomposites was observed. The results obtained from the tensile tests matched well with observations from the SEM micrographs. The epoxy nanocomposites made of functionalized MWCNTs had higher tensile strength as compared to the ones made with the unfunctionalized MWCNTs. Physical interaction occurred between the epoxy matrix and the unfunctionalized CNTs, whereas, due to the functional groups on the surfaces of the functionalized MWCNTs, the interaction between the epoxy matrix and the f-CNTs was of chemical type (covalent bonds).