| abstract |
A high modulus, dimensionally stable film formed via an interpenetrating polyimide network of two polyimide structures, interlocked and bonded on a molecular level. The polyimide components are made from a dianhydride and a diamine. The dianhydrides used are tetravalent aromatic structures represented by n n n where X is a divalent organic group selected from among —CO—, —O—, —S—, —SO 2 —, —CH 2 —, —C(CH 3 ) 2 —, and —C(CF 3 ) 2 — and diamines used are divalent aromatic structure represented by n n n wherein Y is a divalent organic group selected from the group consisting of —CO—, —O—, —S—, —SO 2 —, —CH 2 —, —C(CH 3 ) 2 —, and —C(CF 3 ) 2 —. The end capping agent is a carboxylic anhydride or a silylating agent. The second polyimide is polymerized in the presence of the first polymer thus forming a single phase system. |