| abstract |
A method for continuously preparing solvent-free open-cell and closed-cell polyimide foams, firstly, one or a few of dianhydrides dissolve in or suspend in the polyhydric alcohol and form the precursor A. All kinds of additives dissolve in the polyhydric alcohol and form the precursor B. The aromatic isocyanates with different structure mix well and form the precursor C. Finally the three precursors are mixed foaming by one-step, after solidify, the polyimide foams are obtained with advantage performance. The method does not utilize the volatile solvent that does not participate in the reaction, therefore not existing the process of removing the solvent, it can continuously produce with the double-side heat conveyor belt. CO 2 , the main gas producing in the reaction, causes the system to foam, thus there is no cost on the solvent recovery and it reduces the environment contamination. |