The conductivity and relaxation time data of epoxy compounds having an increasing number of epoxy groups, from 1 to 3, were analysed to check the validity of the Debye-Stokes-Einstein diffusion law (DSE). For mono- and di-epoxide the prediction of the DSE model was verified, while a breakdown of the DSE relation, accounting for a decoupling between translational and rotational motions and well represented by a fractional power law (FDSE), was observed in tri-epoxide at some tens of degrees above the glass transition temperature. The transition between DSE and FDSE behavior seems to be related with the splitting between main and secondary relaxations and with the change of the main relaxation from a Vogel-Fulcher regime to another.
The Check of The Stokes-Einstein-Debye diffusion Law in Epoxies of Increasing Molecular Complexity
CAPACCIOLI, SIMONE;GALLONE, GIUSEPPE CARMINE;
1998-01-01
Abstract
The conductivity and relaxation time data of epoxy compounds having an increasing number of epoxy groups, from 1 to 3, were analysed to check the validity of the Debye-Stokes-Einstein diffusion law (DSE). For mono- and di-epoxide the prediction of the DSE model was verified, while a breakdown of the DSE relation, accounting for a decoupling between translational and rotational motions and well represented by a fractional power law (FDSE), was observed in tri-epoxide at some tens of degrees above the glass transition temperature. The transition between DSE and FDSE behavior seems to be related with the splitting between main and secondary relaxations and with the change of the main relaxation from a Vogel-Fulcher regime to another.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
