EFFECTS OF THERMAL TREATMENTS ON THE VISCOELASTIC BEHAVIOR OF THE INTERPHASE RELAXATION IN A COMPATIBILIZED THERMOSET THERMOPLASTIC BLEND/

Morphology and viscoelastic properties of a compatibilized epoxy/therm oplastic polymer blend were investigated. Transmission electron micros copy (TEM) showed that the introduction of the compatibilizer signific antly reduces the size of the thermoplastic dispersed phase. Dynamic m echanical spectrometry (DMS) revealed an additional loss peak at about 333 K at 1 Hz in the compatibilized ternary blend spectrum which is d etailed as the first unequivocal observation of a 'micromechanical tra nsition' in a compatibilized thermoset/thermoplastic blend. In additio n, the influence of thermal treatments (which were established accordi ng to structural recovery considerations, i.e. accelerated physical ag ing at T-g - 20 K and 'refreshing' process at T-g + 20 K) on the visco elastic behavior (amplitude and temperature position) of the additiona l loss peak was studied. These investigations revealed that the occurr ence of the 'micromechanical transition' on DMS spectra depends signif icantly on the thermal history of the sample and leads to the assumpti on that the viscoelastic behavior of the interphase relaxation is asso ciated with the conditions of confinement of the components in the int erphase zone. (C) 1998 Elsevier Science Ltd. All rights reserved.