An Investigation on the Effect of Sonication Time and Dispersing Medium on the Mechanical Properties of MWCNT/Epoxy Nanocomposites

Abstract

This work studied the effect of sonication time and dispersing medium on the dispersion state of 0.1%wt multi-wall carbon nanotube (MWCNT) in the MWCNT/epoxy nanocomposite system. Epoxy, hardener, and epoxy/solvent were used as dispersing mediums in this study. Tensile strength, strain at failure, Young's modulus and fracture toughness were measured under different dispersion state of MWCNT. The results indicate that with the increase in sonication time, initially there was an increase in tensile strength and fracture toughness values which was followed by a drop in values at longer sonication times. The highest Young's modulus values were seen in epoxy dispersion and the highest tensile strength and fracture toughness values were observed when the hardener was used as dispersing medium. The results also indicated that the effect of sonication time was more pronounced in the case of epoxy dispersion. The effect of time was least when the epoxy / solvent system was used as CNT dispersing medium. It should also be pointed out that the Young's modulus for the nanocomposite sample obtained after 1h of dispersion in hardener showed good agreement with a modified Halpin-Tsai theory. The scanning electron microscope (SEM) was used to characterize the dispersion state of MWCNT. A good dispersion was obtained when either hardener or solvent were selected as the dispersing medium.