Synthesis and characterization of aromatic poly(ether sulfone imide)s derived from sulfonyl bis(ether anhydride)s and aromatic diamines

Two sulfonyl group-containing bis(ether anhydride)s, 4,4'-[sulfonylbis(1,4-phenylene)dioxy] diphthalic anhydride (IV) and 4,4'-[sulfonylbis(2,6-dimethyl-1,4-phenylene)dioxy] diphthalic anhydride (Me-IV), were prepared in three steps starting from the nucleophilic nitrodisplacement reaction of the bisphenolate ions of 4,4'-sulfonyldiphenol and 4,4'-sulfonylbis (2,6-dimethylphenol) with 4-nitrophthalonitrile in N,N-dimethylformamide (DMF). High-molar-mass aromatic poly(ether sulfone imide)s were synthesized via a conventional two-stage procedure from the bis(ether anhydride)s and various aromatic diamines. The inherent viscosities of the intermediate poly(ether sulfone amic acid)s were in the ranges of 0.30-0.47 dL/g for those from IV and 0.64-1.34 dL/g for those from Me-IV. After thermal imidization, the resulting two series of poly(ether sulfone imide)s had inherent viscosities of 0.25-0.49 and 0.39-1.19 dL/g, respectively. Most of the polyimides showed distinct glass transitions on their differential scanning calorimetry (DSC) curves, and their glass transition temperatures (T-g) were recorded between 223-253 and 252-288 degrees C, respectively. The results of thermogravimetry (TG) revealed that all the poly(ether sulfone imide)s showed no significant weight loss before 400 degrees C. The methyl-substituted polymers showed higher T-g's but lower initial decomposition temperatures and less solubility compared to the corresponding unsubstituted polymers. (C) 1998 John Wiley & Sons, Inc.