Optimization of the sealing performance in transient conditions of rubber based hybrid nanocomposites by carbon nanotubes, as assessed by a tailored recovery test

A key property of rubbers for sealing applications is their ability to rapidly recover the deformation
during a fast movement of the counterparts, occurring in a transient deformation phase. In this work, a
simple experimental test method (recovery test) is put forward to mimic the transient phase and to get
insight into the behavior of the material during such phase. The effect of the addition of small quantities
of carbon nanotubes (CNT) to a carbon black filled nitrile butadiene rubber on the sealing ability of the
material was studied. The recovery tests show that the overall recovery behavior is related mostly to the
material stress relaxation behavior, while the recovery behavior at very short times, which is indicative of
the performance during a transient deformation phase, is strongly influenced by the material elastic
modulus and, therefore, it is improved by the presence of CNT in the elastomeric composite.