Toughness Enhancement in ROMP Functionalized Carbon Nanotube/Polydicyclopentadiene Composites

Norbornene-functionalized multiwalled carbon nanotube (MWNT)/dicyclopentadiene (DCPD) nanocomposites have been prepared by ring-opening metathesis polymerization (ROMP). Tensile toughness is shown to increase by more than 900% compared to neat polyDCPD by incorporating just 0.4 wt % functionalized MWNTs. Modest increases in modulus and strength were also observed with increasing nanotube loadings. The effect of norbornene grafted MWNTs on the polymerization kinetics of the resulting cross-linked polyDCPD network was evaluated by differential scanning calorimetry (DSC). The glass-transition temperatures of the composites are shown to increase with addition of functionalized MWNTs. Moreover, a decrease in damping behavior, as measured by dynamic mechanical analysis, is used to estimate the effective polymer−particle interphase thickness.