Nanocomposites of Nitrile (NBR) with Multi-wall Carbon Nanotubes

The nanocomposites of nitrile (NBR) rubber with multi-wall carbon nanotubes (MWCNT) were formulated via melt mixing by blending a master batch with varying amount of virgin NBR in a batch mixer. Dispersion of the MWCNT, curing kinetics, and thermal behavior were assessed using scanning electron microscopy, rheometry, thermogravimetric analysis, respectively. In addition, thermal mechanical behavior, Payne effect, static tensile mechanical properties at both room temperature and 350 F/177 C, and Mullins effect (i.e., cyclic softening), were examined. While the addition of MWCNT was shown to lead to a longer curing time, the MWCNT reinforced the NBR significantly. The tensile behavior (tensile strength and strain to failure) at 350 F showed a much less reduction compared with what was observed for a composite with carbon black. The nanocomposites with only higher concentrations of MWCNT exhibited significant Payne and Mullins effect; Mullins effect is much stronger for the nanocomposites of NBR containing higher concentration of MWCNT than for a composite of NBR with carbon black examined.