Outstanding in-situ CNTs on Fe-pillared nanoclay for high-performance polymer nanocomposites

Abstract

The successful and novel synthesis of in-situ multi-walled carbon nanotubes (MWCNTs) on a pillared montmorillonite (Mt) nanoclay was achieved. These novel nanofillers were mixed with poly(methyl methacrylate) (PMMA) polymer to study electrical properties of these nanocomposites. The trinuclear Fe (III)-acetato complex, [Fe3(OOCCH3)7·OH·nH2O]+NO3−, was synthesized and analyzed by chemical analysis and FTIR spectroscopy, and was used as the precursor for the CNT synthesis. The complex proved to be an excellent precursor for the synthesis of CNTs. CNT-clay hybrid nanofillers with varying CNT contents and qualities were observed and investigated using XRD, TGA, XPS, Raman, SEM, and TEM. The ID/IG of CNTs decreased from 1.92 for 0.5 CEC of the iron complex to 0.72 for 6 CEC CNTs. The XRD indicated that Mt. layers were intercalated with iron species during the ion-exchange process, and further exfoliated due to the growth of CNTs. The synthesis yield increased at higher iron concentrations, i.e., 83.4% for 6 CEC CNTs. The 6, 7, and 8 CEC CNTs exhibited smaller diameter CNTs, 14.6 (±4.4), 18.2 (±4.4), and 16.5 (±6) nanometers, when compared to those of lower catalyst concentrations. The 8 CEC CNTs showed 3.5 S m−1 of conductivity, and ~ 90% of the sp2 structure. The electrical properties of PMMA nanocomposites showed these these CNT-clay hybrid fillers are effective for charge storage applications.