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Method for Tailoring Polyimide Blend Properties

IP.com Disclosure Number: IPCOM000036656D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Feger, C: AUTHOR

Abstract

Disclosed is a method to tailor the properties of polyimides made from mixtures of polyamic acids.

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Method for Tailoring Polyimide Blend Properties

Disclosed is a method to tailor the properties of polyimides made from mixtures of polyamic acids.

Mixing of two or more different homo-polymers leads to new materials which can exhibit the preferable properties of both homo-polymers. Property variations are realized by varying the ratio of the starting materials.

Mixtures of polyamic acids are also expected to give new materials which, after curing, should result in polyimide mixtures. Contrary to most other polymers, solutions of polyamic acids are reactive. In the presence of two or more differing polyamic acids exchange reactions occur. These reactions involve chain cleavage, forming reactive end groups. The latter react with suitable partners, forming again polyamic acid. If more than one type of polyamic acid is present, cross-reactions (exchange reactions) will occur. The resulting materials are no longer homo-polymer mixtures but mixtures of homo-polymers and co-polymers. The composition of the co-polymers depends on the extent of the exchange reactions.

The extent of exchange reactions can be influenced in two different ways: through the mixing time at relatively low temperatures, and through the curing schedule.

Formation of reactive groups through chain cleavage occurs not only in solution but also during the solid-state cycloimidization of polyamic acids. Therefore, exchange reactions are possible also during the cure of polyamic acid mixtures. At the el...