POLYIMIDES BASED ON 9,9-DISUBSTITUTED XANTHENE DIANHYDRIDES

The preparation of a range of 9,9-disubstituted xanthene dianhydrides is discussed, as is their use in the preparation of poly(amic acid)s a nd polyimides. Groups in the 9,9-positions include various combination s of phenyl, substituted phenyl, methyl, ethyl, butyl, trifluoromethyl , perfluoroethyl, perfluoropropyl, cyclotetramethylene, cyclopentameth ylene, hydroxy, and acetoxy. Polyimide films prepared from some of the se new dianhydrides exhibit good mechanical properties, lower dielectr ic constant, lower moisture absorption, and low coefficient of thermal expansion, demonstrating their potential use in electronic applicatio ns. In addition, these new materials may find use in other film, fiber , and part applications.