SYNTHESIS AND PROPERTIES OF POLY(ETHER IMIDE)S DERIVED FROM 2,6-BIS(3,4-DICARBOXYPHENOXY)NAPHTHALENE DIANHYDRIDE AND AROMATIC DIAMINES

A new naphthalene unit-containing bis(ether anhydride), 2,6-bis(3,4-di carboxyphenoxy)naphthalene dianhydride, was synthesized in three steps starting from the nucleophilic nitrodisplacement reaction of 2,6-dihy droxynaphthalene and 4-nitrophthalonitrile in N,N-dimethylformamide (D MF) solution in the presence of potassium carbonate, followed by alkal ine hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). High-molar-mass aroma tic poly(ether imide)s were prepared using a conventional two-step pol ymerization process from the bis(ether anhydride) and various aromatic diamines. The intermediate poly(ether amic acid)s had inherent viscos ities of 0.65-2.03 dL/g. The films of poly( ether imide)s derived from two rigid diamines, i.e. p-phenylenediamine and benzidine, crystalliz ed during the thermal imidization process. The other poly(ether imide) s belonged to amorphous materials and could be fabricated into transpa rent, flexible, and tough films. These aromatic poly(ether imide) film s had yield strengths of 104-131 MPa, tensile strengths of 102-153 MPa , elongation to break of 8-87%, and initial moduli of 1.6-3.2 GPa. The glass transition temperatures (T-g's) of poly(ether imide)s were reco rded in the range of 220-277 degrees C depending on the nature of the diamine moiety. All polymers were stable up to 500 degrees C, with 10% weight loss being recorded above 550 degrees C in both air and nitrog en atmospheres. (C) 1998 John Wiley & Sons, Inc.