An effective route for the fabrication of multi-walled carbon nanotubes-reinforced ROMP-based nanocomposites by solution casting technique

This work reports the solvent-soluble multi-walled carbon nanotubes (MWCNTs), which can be used for the fabrication of ring-opening metathesis polymerization (ROMP)-based nanocomposites by solution casting technique. As the first and most important step of the solution casting technique, the excellent dispersibility of the MWCNTs in different solvents is achieved by the functionalization of the nanotube surface with norbornene oligomers. The norbornene-functionalized MWCNTs (nMWCNTs) have outstanding dispersion stability in water, tetrahydrofuran (THF), acetone, and ethanol, especially the maximum nanotube concentration of 3.9 mg/mL in THF. The incorporation of nMWCNTs into poly(5-ethylidene-2-norbornene) (poly(ENB)) by solution casting technique results in significant improvements in the mechanical properties over the neat poly(ENB) and the pristine MWCNT-reinforced poly(ENB) nanocomposites. The route developed here not only avoids the dramatic increase of the viscosity occurring in the bulk polymerization but also provides the feasibility of high loadings of MWCNT reinforcements, consequently broadening the potential applications of ROMP-based nanocomposites.