| 摘要 |
<p>Curable precursors yielding crosslinked, thermally stable polyimides upon heating comprise (1) at least one anhydride-terminated polyamic acid oligomer obtained by reacting an aromatic tetracarboxylic acid dianhydride with an aromatic diamine and (2) a blocked polyfunctional organic isocyanate that reacts to liberate the free isocyanate at a temperature above the imidization temperature of said oligomer. The molar concentration of isocyanate groups in said composition is substantially equal to the molar concentration of terminal anhydride groups in the oligomer.</p> |
