LIVIU IULIAN PALADE, IVAR E. REIMANIS, ALAN L. GRAHAM, MOSHE GOTTLIEB LINEAR VISCOELASTIC BEHAVIOUR OF HIGHLY CROSSLINKED SILICA REINFORCED POLY(DIMETHYL-SILOXANE) RUBBERS The thermo-mechanical behavior of silica-reinforced crosslinked elastomers has been examined by conducting shear thermorheological experiments and microstructural evaluation on two series of randomly crosslinked poly(dimethyl-siloxane) (PDMS). For all the samples studied here it was found that due to the featureless mechanical spectrum, the time temperature superposition (TTS) principle could not be applied to expand the accessible frequency range by the construction of master curves. Characterization of the filler particles before and after their inclusion into the PDMS matrix was conducted by dynamic light scattering (DLS) and transmission electron microscopy (TEM). These observations are discussed with respect to recent evidence that particle clustering may occur in non-crosslinked systems. Finally, short time high temperature aging (up to 30 hrs) experiments were observed not to influence the viscoelastic behaviour.