Synthesis and properties of poly(ether imide)s based on the bis(ether anhydride)s from hydroquinone and its derivatives

Four bis(ether anhydride)s, 4,4'-(1,4-phenylenedioxy)diphthalic anhydride ( IV), 4,4'-(2,5-tolylenedioxy)-diphthalic anhydride (Me-IV), 4,4'-(2-chloro- 1,4-phenylene dioxy)diphthalic anhydride (Cl-IV), and 4,4'-(2,5 -biphenylen edioxy)diphthalic anhydride (Ph-IV), were prepared in three steps starting from the nucleophilic nitro-displacement reaction of 4-nitrophthalonitrile with the potassium phenoxides of hydroquinone and various substituted hydro quinones such as methylhydroquinone, chloro-hydroquinone, and phenylhydroqu inone in N,N-dimethylformamide, followed by alkaline hydrolysis and dehydra tion. Four series of poly(ether imide)s were prepared from bis(ether anhydr ide)s with various aromatic diamines by a classical two-step procedure. The inherent viscosities of the intermediate poly(amic acid)s were in the rang e of 0.40-2.63 dL/g. Except for those derived from p-phenylenediamine and b enzidine, almost all the poly(amic acid)s could be solution-cast and therma lly converted into transparent, flexible, and tough polyimide films. Introd uction of the chloro or phenyl substituent leads to a decreased crystallini ty and an increased solubility of the polymers. The glass transition temper atures (T-g) of these polyimides were recorded in the range of 204-263 degr ees C. In general, the methyl- and chloro-substituted polyimides exhibited relatively higher T(g)s, whereas the phenyl-substituted ones exhibited slig htly lower T(g)s compared to the corresponding nonsubstituted ones. Thermog ravimetric analysis (TG) showed that 10% weight loss temperatures of all th e polymers were above 500 degrees C either in nitrogen or in air. (C) 1999 John Wiley & Sons, Inc.