Improving the Dispersion and Integration of Single-Walled Carbon Nanotubes in Epoxy Composites through Functionalization

Abstract

Considerable improvement in the dispersion of purified single-walled carbon nanotubes (SWNTs) in an epoxy composite was obtained through functionalization of the SWNTs by using an optimized H2SO4/70% HNO3 acid treatment and subsequent fluorination. Epoxy composites containing 1 wt % nanotubes were processed by dissolving the functionalized SWNTs in dimethylformamide and mixing with the epoxy resin thereafter. The functionalized nanotubes were observed to be highly dispersed and well integrated in the epoxy composites. The enhancement of mechanical properties of the latter was indicated by a 30% increase in modulus and 18% increase in tensile strength. This work demonstrates the practical use of combining acid treatment and fluorination to achieve functionalization and unroping of SWNTs. The functionalized SWNTs can be integrated into epoxy composites through the formation of strong covalent bonds in the course of epoxy ring-opening esterification and curing chemical reactions.

A review on the role of interface in mechanical, thermal, and electrical properties of polymer composites

“…For that purpose, proper chemical treatments are required to attach functional groups to filler surface which can react with the matrix [65][66][67][68][69][70]. Figure 5a-c shows three types of surface functionalization of CNT with polymer chains, hydroxyl, and carboxyl groups, respectively.…”

Epoxy resin nanocomposites reinforced with ionized liquid stabilized carbon nanotubes

“…Many polymers have been applied in the CNTs/polymer nanocomposites for various target applications. The introduction of the CNTs into a polymer matrix has improved the electrical conductivity as well as the mechanical properties of the polymer matrix [11][12][13][14][15][16][17][18].…”

Increased flexural modulus and strength in SWNT/epoxy composites by a new fabrication method

“…A number of researchers have developed techniques to improve the dispersion of the nanotubes in epoxy including ultrasonication [8,9], addition of surfactants [10] and functionalization [11][12][13]. Addition of surfactants and functionalization of the nanotubes prove to be useful in improving the dispersion of nanotubes in the epoxy matrix.…”

“…In terms of mechanical properties, SWNT/epoxy nanocomposites have been found to be either weaker or slightly higher strength than the pure epoxy [13][14][15][16][17][18][19][20]. In most of the reports, more than 1.0 wt% of nanotubes were added to get any improvement in the elastic modulus of the epoxy matrix.…”

“…In most of the reports, more than 1.0 wt% of nanotubes were added to get any improvement in the elastic modulus of the epoxy matrix. Recently Zhu et al reported 30% improvement in Young's modulus of epoxy with 1.0 wt% loading of nanotubes when the nanotubes are functionalized with amino groups [12] or a combination of carboxyl and flouride groups [13] prior to nanocomposite fabrication.…”