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

The thermal and rheological characterizations of seven random, low molecular weight (M-n congruent to 9500 g mol(-1)), H2N-ended polyethersulfone/polyetherethersulfone (PES/PEES) copolymers, at various PES/PEES ratios, were performed. The glass transition temperatures (T-g) were determined by DSC. Degradations were carried out in a thermobalance, under flowing nitrogen, in dynamic heating conditions from 35 degrees C to 650 degrees C. The initial decomposition temperatures (T-i) and the half decomposition temperatures (T-1/2) were directly determined by. TG curves, while the apparent activation energies of degradation (E-a) were obtained by the Kissinger method. In addition, the complex viscosities (eta*) of the molten polymers were determined in experimental conditions of linear viscoelasticity. T-g, E-a and eta* values increased linearly with PES% content, while T-i and T-1/2 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. (c) 2006 Elsevier Ltd. All rights reserved.