The influence of chain‐ends on the thermal and rheological properties of some 40/60 PES/PEES copolymers

Abstract

Abstract Four random, differently ended (Cl, NH 2 , OH, and COO − ), polyethersulfone/polyetherethersulfone (PES/PEES) copolymers were studied to investigate the influence of chain ends on thermal and rheological behaviors. The number average molar mass ( M n ≈ 9500 g·mol −1 ) and the PES/PEES ratio (40/60) of all copolymers investigated were checked by 1 H NMR spectra. Thermal degradations were carried out in the scanning mode and initial decomposition temperatures ( T i ) and activation energy values of degradation ( E a ) were obtained. Glass transition temperature ( T g ) was determined by differential scanning calorimetry and complex viscosity (η*) by rheological measurements in isothermal heating conditions ( T = 270°C). All parameters determined were largely affected by copolymer chain ends and decreased according to the same order, OH > NH 2 > Cl > COO − . The results were discussed and interpreted. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers