摘要 |
Polyimides, especially thermoset polyimides such as those prepared by the reaction of p-phenylenediamine with 4,4'-hexafluoroisopropylidenebis(phthalic anhydride) and nadic ester, are converted to monomers which may be recycled for polyimide synthesis by heating with a solution of an alkali metal hydroxide, such as lithium hydroxide or sodium hydroxide, in a dipolar aprotic solvent such as N-methylpyrrolidone. The products are the diamine and the tetracarboxylic acid alkali metal salt corresponding to the dianhydride.
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