초록 ▼

A shaped article composed of an aromatic polyimide has a hollow, essentially spherical structure and a particle size of about 100 to about 1500 .mu.m, a density of about 1 to about 6 pounds/ft.sup.3 and a volume change of 1 to about 20% by a pressure treatment of 30 psi for 10 minutes at room temper

A shaped article composed of an aromatic polyimide has a hollow, essentially spherical structure and a particle size of about 100 to about 1500 .mu.m, a density of about 1 to about 6 pounds/ft.sup.3 and a volume change of 1 to about 20% by a pressure treatment of 30 psi for 10 minutes at room temperature. A syntactic foam, made of a multiplicity of the shaped articles which are bounded together by a matrix resin to form an integral composite structure, has a density of about 3 to about 30 pounds/ft.sup.3 and a compression strength of about 100 to about 1400 pounds/in.sup.2.

대표청구항 ▼

[ We claim:] [1.] A process for preparing a multiplicity of shaped articles in the form of hollow aromatic polyimide micorspheres having a particle size of from about 100 to about 1500 microns, which process comprises:(1) providing an aromatic polyimide precursor solid residuum, which is an admixtur

[ We claim:] [1.] A process for preparing a multiplicity of shaped articles in the form of hollow aromatic polyimide micorspheres having a particle size of from about 100 to about 1500 microns, which process comprises:(1) providing an aromatic polyimide precursor solid residuum, which is an admixture of an aromatic compound (A), which is an aromatic dianhydride or a derivative of an aromatic dianhydride, and an aromatic compound (B), which is an aromatic diamine or a derivative of an aromatic diamine, plus a complexing agent (C), which is complexed with the admixture, by hydrogen bonding, the complexing agent (C) being present in an amount sufficient to provide from about 1 to about 15% by weight, based on the total weight of the polyimide precursor solid residuum;(2) charging the aromatic polyimide precursor solid residuum into a non-confined vessel;(3) heating the aromatic polyimide precursor solid residuum in the non-confined vessel to a temperature between about 100.degree. C. and 200.degree. C. to produce a multiplicity of shaped articles from the aromatic polyimide precursor solid residuum in the non-confined vessel.(4) heating the multiplicity of shaped articles to a temperature between about 200.degree. C. and 300.degree. C. to produce a multiplicity of thermally imidized shaped articles; and(5) cooling the multiplicity of thermally imidized shaped articles for subsequent utilization.