Synthesis and properties of polysulfonamides containing thiophene links

In order to study the synthesis and properties of polysulfonamides containing thiophene links, 2,2‐bis(5‐chlorosulfonyl‐2‐thienyl)propane [BCTP], 2,2‐bis(5‐chlorosulfonyl‐2‐thienyl)butane [BCTB], 1,1‐bis(5‐chlorosulfonyl‐2‐thienyl)cyclohexane [BCTC], and 2,4‐dichlorosulfonyl thiophene [DCST] were prepared and interfacial polycondensations with various aliphatic diamines were carried out. The resulting polymers had inherent viscosities in the range of 0.13–0.41 dL/g and showed high extent of moisture absorptions. Most of the polysulfonamides were soluble in electron‐donating solvents such as pyridine, DMF, DMSO, NMP, etc. These polysulfonamides exhibited relatively good thermal stabilities. The TGA data revealed 5% weight losses at 275–405°C and residual weights at 500°C were 13–40% under nitrogen. It was also found that dithienyldisulfonyl chlorides produced more thermally stable polymers than DCST, which were comparable to common polysulfonamides from aromatic disulfonyl chlorides.