Polypyrrole/montmorillonite and polypyrrole/ghassoul intercalates as a source of graphite and multi-layer graphene: Preparation of nanocomposites exhibiting strongly anisotropic electrical conductivity

Abstract

Nanocomposite tablets containing graphite and multi-layer graphene formed from polypyrrole (PPy) in the presence of Na-montmorillonite (Mt) and Moroccan clay ghassoul (Gha) were prepared by the calcination of PPy/Mt and PPy/Gha intercalates in argon at 1300 degrees C. XPS, XRD, Raman, and TEM analyses confirmed that PPy can serve as a precursor of graphite and multi-layer graphene. Although the calcined tablets PPy/Mt(c) and PPy/Gha(c) contain similar to 1/3 of the carbon content compared to a calcined PPy tablet (PPy(c)), the mean values of inplane electrical conductivity (2476 S/m for PPy/Mt(c) and 2289 S/m for PPy/Gha(c)) are higher than 1837 S/m obtained for PPy(c). Strong anisotropy in electrical conductivity (three orders of magnitude) was achieved for PPy/Mt(c) and PPy/Gha(c) tablets. The similar conductivity, as well as density, porosity, and hardness of PPy/Mt (c) and PPy/Gha(c), demonstrate that Mt and Gha in conjunction with PPy are suitable for the preparation of nanocomposites with strongly anisotropic electrical conductivity.