Influence of nanotube content on the mechanical and thermo-mechanical behaviour of –COOH functionalized MWNTs/epoxy composites

Functionalized multi-wall carbon nanotubes (MWNTs) with carboxylic acid group (–COOH) have been utilized for the preparation of epoxy nanocomposites. Composites were synthesized using three different wt% (0.5, 0.75 and 1) of MWNTs via the solution mixing technique followed by ultrasonication. Mechanical and thermo-mechanical properties of the fabricated composites have been experimented for the suitability of this material in a variety of structural applications. The flexural modulus, strength, hardness, impact strength and storage modulus increased upon increasing MWNTs contents. Best results have been observed in nanocomposites with 0.75 wt% nanotubes loading, which showed 101, 166 and 61% enhancement in the flexural modulus, hardness and storage modulus, respectively, compared to neat epoxy. Achievement of uniform dispersion and hence formation of improved interface between nanotubes and epoxy was the reason behind the maximum enhancement at this wt%, which is further evidenced by the fracture surface morphology obtained from microscopical investigations.