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

Abstract

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-phenylenedioxy)diphthalic anhydride (Cl-IV), and 4,4'-(2,5-biphenylenedioxy)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 hydroquinones such as methylhydroquinone, chlorohydroquinone, and phenylhydroquinone in N,N-dimethylformamide, followed by alkaline hydrolysis and dehydration. Four series of poly(ether imide)s were prepared from bis(ether anhydride)s with various aromatic diamines by a classical two-step procedure. The inherent viscosities of the intermediate poly(amic acid)s were in the range of 0.40-2.63 dL/g. Except for those derived from p-phenylenediamine and benzidine, almost all the poly(amic acid)s could be solution-cast and thermally converted into transparent, flexible, and tough polyimide films. Introduction of the chloro or phenyl substituent leads to a decreased crystallinity and an increased solubility of the polymers. The glass transition temperatures (T g ) of these polyimides were recorded in the range of 204-263°C. In general, the methyl- and chloro-substituted polyimides exhibited relatively higher T g s, whereas the phenyl-substituted ones exhibited slightly lower T g s compared to the corresponding nonsubstituted ones. Thermogravimetric analysis (TG) showed that 10% weight loss temperatures of all the polymers were above 500°C either in nitrogen or in air.