COMPARATIVE-STUDY ON POLYIMIDES FROM 3,3'-LINKED AND 4,4'-LINKED DIPHTHALIC ANHYDRIDE

1,4-Bis(2,3-dicarboxyphenoxy)benzene dianhydride, 1,4-bis (3,4-dicarbo xyphenoxy)benzene dianhydride, bis(2,3-dicarboxyphenoxy) sulfide dianh ydride, bis (3,4-dicarboxyphenoxy)sulfide dianhydride, and 2,3,3',4'-t etracarboxy diphenyl sulfide dianhydride were synthesized from 3-chlor ophthalic anhydride and 4-chlorophthalic anhydride. Bis(2,3-dicarboxyp henyl)sulfone and bis(3,4-dicarboxyphenyl) sulfone were obtained by th e oxidation of the corresponding bis(dicarboxyphenyl)sulfide by hydrog en peroxide. The polyimides from the dianhydrides mentioned above and 4,4'-oxydianiline were prepared. The properties, such as dynamic mecha nical behavior, thermooxidative stability, stress-strain behavior, che mical resistance, and permeability to some gases have been in investig ated for the isomeric polyimides. (C) 1996 John Wiley & Sons, Inc.