Effective approaches for the preparation of organo-modified multi-walled carbon nanotubes and the corresponding MWCNT/polymer nanocomposites

Abstract

Carbon nanotubes (CNTs) are promising nanomaterials for the preparation of nanohybrids and nanocomposites with polymers. In the preparation processes, surface modification and functionalization of CNTs have key roles to enhance the compatibility in organic solvents or water for solution processing routes; furthermore, they improve the interfacial compatibility between CNTs and the polymer matrix to avoid CNT aggregation in CNT/polymer nanocomposites. Hence, we have developed three approaches for directly reacting chemical agents and polymer chains with multi-walled CNTs (MWCNTs). The methods are: (i) sequential atom transfer radical addition to MWCNTs, which conveniently builds up polymer architectures on MWCNT surfaces; (ii) ozone-mediated addition reaction, which effectively chemically bonds non-reactive polymer chains to MWCNTs; and (iii) Diels-Alder reaction-mediated MWCNT functionalization, which achieves thermally reversible functionalization/de-functionalization of MWCNTs. On the basis of the new reaction routes, the scopes of nanohybrids and nanocomposites of MWCNT/polymers and their properties and functions have been significantly enhanced and extended. Some examples are discussed in this review.