Methods of preparing polyimides and artifacts composed thereof
AssigneeInternational Harvester Company
InventorsJohn Gagliani, Raymond Lee, Anthony L. Wilcoxson
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Abstract
Methods of converting essentially unpolymerized precursors into polyimides in which the precursors are exposed to microwave radiation. Preheating, thermal post-curing, and other techniques may be employed to promote the development of optimum properties; and reinforcements can be employed to impart strength and rigidity to the final product. Also disclosed are processes for making various composite artifacts in which non-polymeric precursors are converted to polyimides by using the techniques described above.
Claims11
A method of preparing a reinforced polyimide foam comprising the steps of preparing a liquid resin containing substantially equimolar and essentially unreacted amounts of a 3,3',4,4'-benzophenonetetracarboxylic acid half ester, at least two primary diamines, and a solvent for said ester and said diamines;
- mixing a multi-partite reinforcement with said resin;
- evaporating the solvent from the mixture;
- and converting the ester and diamine constituents of the mixture to a polyimide by subsequently exposing said mixture to microwave radiation for periods of sufficient duration to develop a polyimide chemical structure and a cellular physical structure.
Dependencies are inferred from the claim text.