Tuning the thermal and mechanical properties of PSU by post-polymerization Friedel-Crafts acylation

Abstract

This study describes the synthesis and characterization of poly(ether sulfone) Udel® (PSU-Udel) derivatives by means of post-polymerization Friedel-Crafts acylation. PSU derivatives containing acetyl, hexanoyl and decanoyl side groups were prepared, with different acylation degrees, and their thermal and mechanical properties were evaluated. It was observed that the Tg of the derivatives decreases linearly with the acylation degree (AD) (184 °C for neat PSU, 169 °C and 140 °C for the acetylated derivative (PSU-A) with AD of 10% and 19%, respectively) and the slope is dependent on the length of the acyl group, being more pronounced for PSU-A. The thermal stability is not significantly affected. Stress relaxation tests demonstrate the influence of the side groups on the viscous response of blends of the derivatives with neat PSU (50/50% wt), as shown by viscoelastic models. The results demonstrate the potential for the use of post-polymerization acylation to adjust the thermal and mechanical properties of PSU aimed at specific applications.