Rheological Study Bringing New Insights into PET/PC Reactive Blends

Extruded poly(ethylene terephthalate)/polycarbonate (PET/PC) blends, with/without cobalt catalyst and at different polymer ratios, were prepared. Rheological behaviour was discussed in terms of storage (G′) and loss (G″) moduli, loss tangent (Tan δ) and viscosity (η). Both G′ and G″ increased as a function of frequency for all blends. PET was the matrix in the blends with 80 and 50 wt% of polyester but in the PC rich-blend an inversion was observed. In all cases, lower Tan δ values were achieved at high frequencies. The viscosity behaviour showed a catalyst dependency. PET dictated the rheological properties of the blends without catalyst whereas PC governed blends with catalyst. Alcoholysis and acidolysis reactions plus a transesterification reaction occurred on the interface was dependent on the matrix component. These reactions seem to occur at higher extent in blends in which PET is the matrix but the inverse happened in the PC rich-blend.