Thermal and rheological behaviours of some random aromatic amino-ended polyethersulfone/polyetherethersulfone copolymers

The thermal and rheological characterizations of seven random, low molecular weight (Mn ≅ 9500 g mol−1), H2N-ended polyethersulfone/polyetherethersulfone (PES/PEES) copolymers, at various PES/PEES ratios, were performed. The glass transition temperatures (Tg) were determined by DSC. Degradations were carried out in a thermobalance, under flowing nitrogen, in dynamic heating conditions from 35 °C to 650 °C. The initial decomposition temperatures (Ti) and the half decomposition temperatures (T1/2) were directly determined by TG curves, while the apparent activation energies of degradation (Ea) were obtained by the Kissinger method. In addition, the complex viscosities (η∗) of the molten polymers were determined in experimental conditions of linear viscoelasticity. Tg, Ea and η∗ values increased linearly with PES% content, while Ti and T1/2 values showed opposite behaviour. In every case both PES and PEES homopolymers felt outside linearity. The results obtained are discussed and interpreted, and compared with those of corresponding Cl-ended copolymers previously studied.