Structure–property relationships in poly(olefin sulfone) copolymers and terpolymers derived from linear and cyclic alkenes

Abstract

Poly(olefin sulfone)s (POSs), formed via alternating copolymerizations of sulfur dioxide (SO₂) and olefins, remain understudied with respect to systematic structure–property relationships. In this work, we report the synthesis and thermal characterization of five POS copolymers and 24 terpolymers derived from linear alkenes (1-hexene, 1-decene) and cycloalkenes (cyclopentene, cyclohexene, norbornene). All polymers were prepared by free radical polymerization at −30 °C initiated by tert-butyl hydroperoxide. Molecular characterization by ¹H and ¹³C NMR spectroscopy, FTIR spectroscopy, and size-exclusion chromatography with multi-angle light scattering (SEC-MALS) confirmed polymer structures and high molecular weights (weight-average molecular weight, M_w = 100–8000 kg mol⁻¹). Thermogravimetric analysis showed decomposition temperatures at 50% weight loss (T_d,50%) for the copolymers ranged from 292 to 317 °C, with the highest stability observed in the norbornene-containing copolymers and terpolymers. Differential scanning calorimetry revealed glass transition temperatures (T_g = 46–184 °C) that increased systematically with the incorporation of cyclic comonomers. These results show systematic structure–property relationships in POS co- and terpolymers and demonstrate how polymer structure governs thermal behavior, providing guidance for the design of thermally robust sulfone-based polymers for advanced applications.