| 摘要 |
<p>A method of filling a honeycomb or similar multi-cell structure with a very uniform polyimide foam. A very uniform layer of finely divided polyimide foam precursor powder is formed on a mold-release coated surface within cells of a honeycomb structure on the surface. The uniform layer within the cells may be formed by forming a uniform precursor powder layer on the surface and pressing the honeycomb down through the layer. Or, precursor powder may be sifted uniformly into the cells of a honeycomb structure resting on the surface while moving the sifter across the honeycomb structure. A sheet having a mold-release surface is placed over the honeycomb. The assembly is then heated, such as in a heated platen press, to the foaming and condensation temperature of the precursor. Each cell is filled with a very uniform, controlled density, polyimide foam. The assembly may be further heated to the full cure temperature of the polyimide material. <IMAGE></p> |
