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.