Modeling of creep for multiwall carbon nanotube/epoxy nanocomposite

The effect of multiwall carbon nanotubes (MWCNTs) on creep of epoxy matrix was evaluated on the basis of short-term creep-recovery tests performed at different stresses and temperatures. Six different compositions of MWCNT and bisphenol A epoxy resin (0-3.8 wt % of MWCNTs) were investigated. Slight reduction of creep compliance, strain rate, and residual strain were revealed experimentally for nanocomposite comparing to the neat resin. The development of viscoelastic strain for creep stage was described by the use of time-temperature-strain superposition principle with the parameters obtained from the approximation of recovery stage using modified Schapery model. The model accounted for the effect of strain on the viscoelastic strain rate for recovery stage. Its application gave better results for approximation of a series of recovery curves at different temperatures and stresses than of time-stress superposition model.