Functionalised multi-walled carbon nanotubes for epoxy nanocomposites with improved performance

BACKGROUND: Carbon nanotubes (CNTs) are fast becoming key components in the production of high-strength composite materials. Two methods to prepare nanocomposites by covalent bonding between an epoxy matrix and functionalised CNTs that acted as cross-linkers during polymerisation were investigated. RESULTS: In the standard method, 1 wt% functionalised CNTs was dispersed in epoxy, hardener was added and the composite was cured. In the masterbatch approach, 1 wt% functionalised CNTs was mixed with epoxy in the presence of triethylamine accelerator, then cured. This yielded partially cured epoxy; additional hardener was required to achieve complete curing. Improvements were observed in storage modulus (E'), flexural modulus (E-B), wear resistance and hardness. Thermal stability did not change appreciably for samples prepared by either the standard or masterbatch methods. Variations in the results obtained as a function of preparation method, functionalised CNTs and hardener used are discussed. CONCLUSION: Epoxy nanocomposites having improved mechanical properties were obtained by incorporating functionalised CNTs. Better interaction between the epoxy and CNT was achieved using the masterbatch method; this was attributed to covalent bonding between the CNTs and epoxy. However, optimisation of the CNTs, accelerator and hardener used in composite preparation is required to obtain improved physical properties. (c) 2009 Society of Chemical Industry