Synergy between single-walled carbon nanotubes and ionic liquid in epoxy resin nanocomposites

The present work describes new epoxy matrix (ER) nanocomposite materials obtained by addition of a 0.5 wt% of single-walled carbon nanotubes (ER + SWCNT), a 1.5 wt% of the ionic liquid (IL) 1-octyl-3-methylimidazolium tetrafluoroborate (ER + IL), a mixture of a 0.5 wt% of SWCNT and a 1.5 wt% of IL (ER + SWCNT + IL), or a 0.5 wt% of an hybrid nanophase of SWCNTs modified by IL (ER + SWCNTm), obtained after dispersion of SWCNTs in IL and removal of excess IL. The influence of the additives on the curing process of the epoxy resin on the thermal and dynamic-mechanical properties has been studied by FTIR and DSC. The crosslink density has been calculated from dynamic mechanical properties. To determine the performance of the materials under adhesive and abrasive wear, the tribological behaviour of the new nanocomposites has been compared with that of the neat epoxy resin under pin-on-disc sliding conditions and under microscratching abrasion tests. The main findings are that the best friction reduction and antiwear performances are due to the synergistic effect of the combination of SWCNT and IL additives (ER + SWCNT + IL) and that very similar effects can be achieved with SWCNT previously modified by IL (ER + SWCNTm). The higher thermal stability and crosslink density of (ER + SWCNT + IL) makes it a suitable candidate for tribological applications.