| 摘要 |
The invention comprises: (I) a method of preparing polyimides comprising interacting a diamine and a tetraester of a tetracarboxylic acid; and (II) compounds of formula <FORM:1094251/C3/1> where A is ethylene or trimethylene, B is organic and n is an integer. Diamines suitable for (I) may be acyclic, alicyclic, aromatic or heterocyclic and may contain additional functional groups containing oxygens, nitrogen, sulphur, phosphorus or silicon. Those specified are bis (aminophenyl) ether, benzidine, m-bis (aminomethyl) benzene, hexamethylene diamine and 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane. The tetracarboxylic acid may be one capable of being converted to a dianhydride, e.g. benzophenone tetracarboxylic acid, cyclopentane tetracarboxylic acid, 2,2,6,6-tetra (b - carboxyethyl) cyclohexanone or 2,2,5,5 - tetra (carboxyethyl) cyclopentanone. The ester may be that of an alcohol having 1-8 carbon atoms, e.g. MeOH or isopropanol. The polymer may be produced by dissolving the diamine in the tetraester, optionally in a mould, and heating the solution to 180-400 DEG C. at atmospheric or reduced pressure. Reaction may be facilitated by the presence of an esterification catalyst, e.g. a mineral acid, alkali metal alkoxide, or titinate ester. The compounds of (II) may be prepared by the method of (I). |
