Multicyclic Poly(ether sulfone)s Derived from Tris(4‐hydroxyphenyl)ethane

Polycondensations of 4,4′‐difluorodiphenylsulfone with tris(4‐hydroxy phenyl)ethane were performed in DMSO with variation of feed ratio and concentration. For feed ratios of 1.0:1.3–1.0:1.5, soluble multicyclic poly(ether sulfone)s were obtained when the monomer concentration was below 0.05 M . The conversions were never complete under standard conditions, and doubling the reaction time yielded perfect multicyclic products free of endgroups; however, a small fraction of the product was crosslinked under these conditions. Quite similar results were obtained with 4,4′‐dichlorodiphenylsulfone at higher temperatures. When K₂CO₃ was replaced by tertiary amines, conversions and molecular weights were lower. The multicyclic poly(ether sulfone)s were characterized by MALDI‐TOF mass spectrometry, SEC, and DSC measurements. Broad molecular weight distributions with polydispersities in the range of 2.4–3.9 were found, and, surprisingly, two glass transitions were detectable in the DSC heating curves.