Effect of graphene nanoplatelets on the dielectric permittivity and segmental motions of electrospun poly(ethylene-co-vinyl alcohol) nanofibers

The influence of the addition graphene nanoplatelets (GNPs) on intra/inter – molecular segmental motions poly(ethylene-co-vinyl alcohol) (EVOH) was assessed by means dielectric thermal analysis (DETA). relaxation spectra were studied in terms permittivity (??) and loss tangent (tan ?) at wide ranges frequency (from 10?2 to 107 Hz) temperature -150 140 °C). Two zones disthinguished. Below glass transition (Tg), two ?-relaxations observed, which are characteristic local modes mobility EVOH side groups, related different surroundings ethylene or vinyl alcohol units. At higher temperatures, ?-relaxation vicinities determined. activation explained an Arrhenius model, showed energies (Ea) around 55 80 kJ·mol?1. Vogel-Fulcher-Tammann-Hesse (VFTH) model. study dynamics increase dynamic fragility parameters with GNPs. increased preferential concentrations In particular, GNPs up 0.5 wt% electrospun EVOH/GNPs nanocomposite fibers, specially low frequencies.