US 5,135,959 A · Method of impregnating reticulated foam with polymide foam and products thereof

Abstract

A method of forming complex polyimide foam shapes by impregnating a low density, open cell, reticulated form with polymide foam precursor, placing the combination in a mold, closing the mold, then heating the assembly to the foaming and curing temperatures of the precursor. As the powdered precursor expands, it spreads throughout the reticulated foam producing a product having substantially uniform density and polyimide foam characteristics. If desired, the reticulated foam can be removed from the product by using a material that outgasses and boils away at polyimide processing temperatures. Radar absorbing materials may be incorporated in the reticulated foam so that the final product will have uniformly distributed radar absorbing components with the desirable high temperature resistance and other properties of polyimide foams.

Claims10

Dependent claims

The method of making complex polyimide foam products which comprises the steps of:

providing a reticulated foam shape having substantially the dimensions of the intended polyimide foam product;
impregnating said reticulated foam with a polyimide foam precursor;
heating said impregnated reticulated foam in a substantially closed mold to the foaming temperature of the polyimide foam precursor;
further heating the resulting assembly to the curing temperature of said polyimide foam for a time sufficient for substantially complete cure;
said reticulated foam material having a vaporization temperature below the degradation temperature of the cured polyimide foam;
and
heating said assembly to a temperature above the vaporization temperature of said reticulated foam material but below the degradation temperature of said cured polyimide foam;
whereby said reticulated foam is substantially eliminated.

5 more elements

Dependencies are inferred from the claim text.

Method of impregnating reticulated foam with polymide foam and products thereof

Life of this patent

Method of impregnating reticulated foam with polymide foam and products thereof

Life of this patent

Abstract

Claims10