Carbon Nanotubes−Polypropylene Nanocomposites for Electrostatic Discharge Applications

Abstract

We report a novel method for enhancing the dispersion of modified multiwalled carbon nanotubes (MWNTs) in a polypropylene (PP) matrix for electrostatic discharge applications. The surfaces of MWNTs were modified with octadecylamine (ODA) via CF4 plasma-assisted fluorination and subsequent alkylamination. The number of fluorine groups on the MWNT surface was controlled by varying the CF4 plasma treatment conditions. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) revealed that reaction of the fluorinated MWNTs and octadecylamine (ODA) was strongly affected by solvent quality and reaction temperature. The resulting MWNT/PP nanocomposites exhibited a much finer dispersion in the insulating PP matrix than was observed for nonmodified MWNTs, leading to an enhanced electrical conductance at low MWNT loading (2 wt %). Furthermore, the nanocomposites showed significantly improved mechanical properties; the storage modulus (G′) and complex viscosity (η*) increased significantly in the low-frequency region as MWNT loading was increased, showing a rheological percolation threshold at 1 wt % MWNT loading. This effective method can be applied to the fabrication of other carbon nanotube-based polymer nanocomposites for potential development into electrostatic dissipative (ESD) materials with high mechanical strength and for other high-performance industrial applications.