Ethynyl‐terminated polysulfones: Synthesis and characterization

Hydroxy‐terminated polysulfones (PSs) of number‐average molecular weights from 3000 to 26,000 g/mol were converted to the corresponding 4‐ethynylbenzoate–terminated PS through a three‐step synthesis. The initial step involved the reaction of the hydroxy precursor with 4‐bromobenzoyl chloride followed by displacement of the bromo group with trimethylsilylacetylene using a palladium catalyst. The trimethylsilyl group was subsequently cleaved with a weak base to afford the ethynylbenzoate‐terminated PS. A more direct route to the ethynylbenzoate‐terminated PS involved the reaction of the hydroxy‐terminated PS with 4‐ethynylbenzoyl chloride. The trimethylsilylethynyl and ethynyl groups undergo a thermally induced reaction to provide modified PS with better solvent resistance and higher apparent glass transition temperatures than an unmodified linear PS. The physical properties of the modified PS are compared with those of a linear PS.