In this paper, the effects of carbon nanotubes (CNT) implantation and sisal fibre size on the electrical properties of sisal fibre-reinforced epoxy composites are reported. For this purpose, the epoxy composites reinforced with CNT-implanted sisal fibre of 5 mm and 10 mm lengths were prepared by hand moulding and samples characterized for their electrical properties, such as dielectric constant (ε′), dielectric dissipation factor (tan δ) and AC conductivity (σ ac ) at different temperatures and frequencies. It was observed that the dielectric constant increases with increase in temperature and decreases with increase in frequency from 500 Hz to 5 KHz. Interestingly, the sample having CNT-implanted sisal fibre of 5 mm length exhibited the highest value of dielectric constant than the one with length 10 mm. This is attributed to the increased surface area of sisal fibre and enhancement of the interfacial polarization. At a constant volume and a length of 5 mm of the fibres, the number of interfaces per unit volume element is high and results in a higher interfacial polarization. The interfaces decrease as the fibre length increases, and therefore, the value of ε′ decreases at 10 mm fibre length. The peak value of the dielectric constant decreases with increasing frequency. A continuous decrease in dissipation factor (tan δ) with increasing frequency for all samples was observed, while at lower temperatures, the values of tan δ remains approximately same. The AC conductivity for 5 mm length sisal epoxy composite and 10 mm length sisal fibre-epoxy composites is higher than that of pure epoxy at all the frequencies.
An attempt is made to study the effect of low weight percentage multiwall carbon nanotube (MWCNT) powder on dielectric properties of MWCNT reinforced epoxy composites. For that MWCNT (of different low weight percentage) reinforced epoxy composite was prepared by dispersing the MWCNT in resin. Samples were prepared by solution casting process and characterized for their dielectric properties such as dielectric constant (" 0 ), dielectric dissipation factor (tan ) and AC conductivity ( ac ). The main objective is the investigation of the dielectric properties of the prepared samples at the low weight percentage of the filler at different temperatures and frequencies. From the two mechanisms of electrical conduction, first the leakage current obtained by the formation of a percolation network in the matrix and the other by tunneling of electrons formed among conductors nearby (tunneling current); here we are getting conduction by the second mechanism. Generally, leakage current makes more contribution to conductivity than tunneling current. Dielectric dissipation factor at 250 Hz frequency is greater than all other frequencies and starts increasing from 60 C. The peak height of the transition temperature decreases with increasing frequency. This study shows that the addition of a low weight percentage of MWCNT can modify considerably the electrical behavior of epoxy nanocomposites without chemical functionalization of filler.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.