摘要 |
<p>A soluble polyimide derived from dehydration of a polyamic acid which is the liquid phase condensation reaction product of a solution in aprotic solvent of approximately equimolar amounts of aromatic dianhydride and aromatic diamine. At least 50 mole % of the dianhydride must have ring linkages which prevent conjugation between the rings and at least 20 mole % of the diamine must contain electron withdrawing groups.</p> |