PERFLUORINATED POLYIMIDE, PERFLUORINATED POLY(AMIC ACID), STARTING COMPOUNDS THEREFOR, AND METHODS FOR PREPARING THEM

摘要

A perfluorinated polyimide comprising a repeating unit represented by general formula (1): (see fig. I) and a perfluorinated poly(amic acid) comprising a repeating unit represented by general formula (6): (see fig. II) wherein R1 is a tetravalent organic group; and R2 is a divalent organic group, provided that chemical bonds between carbon atoms and monovalent elements contained in R1 and R2 are exclusively carbon-to-fluorine bonds; methods for preparing them; and optical material including the perfluorinated polyimide. l,4-Bis(3,4-dicarboxytrifluorophenoxy)-tetrafluorobenzene dianhydride, 1,4-difluoropyro-mellitic anhydride, 1,4 bis(3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene, 1,4-difluoropyromellitic acid, and 1,4-bis(3,4-dicyanotrifluorophenoxy) tetrafluorobenzene as well as methods preparing them. The perfluorinated polyimide has a thermal stability and has a low optical loss in an optical communication wavelength region (0.8 to 1.7 .mu.m).