Studies of Carboxyl-Functionalized Multi-Wall Carbon Nanotubes and Mechanical Properties of its MWCNTs-OPC Cement Composites

Abstract

This study successfully grafted multiwalled carbon nanotubes (MWCNTs) with carboxyl group (MWCNTs-COOH) via concentrated nitric acid oxidation reaction. The morphologies of MWCNTs oxidized under various conditions and the extent of dispersion of the MWCNTs in the cement matrix were characterized using fourier transform infrared spectroscopy (FTIR). This investigation also optimized the mechanical properties of MWCNTs-OPC cement composites by utilizing pristine MWCNTs (P-MWCNTs) and modified MWCNTs (MWCNTs-COOH) through a combination of dispersion method. Micrographs of MWCNTs incorporated cement samples revealed uniform dispersion of MWCNTs in cement, good interfacial adhesion between MWCNTs and cement, and improved interfacial bonding between MWCNTs-OPC cement at 0.4 wt.% loading. An improved dispersion and hence an improved crosslink interaction between MWCNTs-COOH and cement lead to the stronger shift of the mechanical properties of the cement composites.