Preparation of small pore diameter carbon foam

Abstract

The invention discloses a method for preparing foam carbon by a supercritical technology, which pertains to the preparation technology of foam carbon and comprises the following processes: high softening point asphalt and a foaming agent are subjected to foaming through fast pressure relief under a supercritical condition, then the foamed asphalt is in put in an oxidizing furnace for being subjected to oxidation stabilization treatment, then carbonization and graphitization hot treatments are carried out under the protection of inert gases, thus obtaining the foam carbon product. The invention has the advantages that: by adopting the supercritical fluid technology, the aperture of the prepared foam carbon is greatly reduced compared with other methods and generally ranges from 10 to 200 mu m with narrow aperture distribution; the hole wall is smooth and the microcracks are less; and the foam carbon of the pore structure not only can be used as the materials of heat conducting, heat insulation, electromagnetic shielding and electrodes, but also can be applied to the fields of biological sewage treatment, catalysis, energy saving buildings and the like.

Description

Technical field: [0001] The invention relates to a preparation method of small foamed carbon, in particular to a preparation method of foamed carbon with an average pore diameter of 10 to 200 μm and smooth pore walls. Background technique: [0002] As a three-dimensional ordered honeycomb carbonaceous functional material, foamed carbon has excellent characteristics such as high strength, high thermal conductivity, high electrical conductivity, low density and low thermal expansion coefficient. It becomes heat transfer, mass transfer, electrical conductivity, and wave absorption. The research hotspots in the field of materials, especially the application of thermal conductive materials in the aerospace and electronics fields, have gradually gained wide attention. At the same time, the use of foamed carbon as electromagnetic shielding material, sewage treatment biological solid bacteria carrier material, energy-saving building material, etc. has also attracted increasing attention ...

AI Technical Summary

Problems solved by technology

At present, high-pressure nitriding and self-foaming methods are the two main foaming methods for preparing foamed carbon. Under the foaming conditions of 500-800°C / ~7MPa, the average pore size of foamed carbon can be effectively controlled at 200-500μm. Reducing the pore size will require higher foaming pressure, which will put forward higher requirements for equipment and operation; in addition, because nitrogen is a non-polar molecule, it has low compatibility with high-softening point asphalt, resulting in high-pressure nitriding. The pore structure of the foamed carbon made by foaming is not uniform, and the open cell ratio of the foamed carbon made by self-foaming with the pyrolysis gas of carbon-rich raw materials is low, which is not conducive to heat transfer in the fluid phase, and the average pore size is generally 200-500 μm

The oil / water emulsion polymerization method has advantages in controlling the pore structure of carbon foam with a pore size of 2-50 μm, but it is not easy to use pitch-like carbonaceous precursors such as mesophase pitch with high graphitizability as raw materials to obtain high thermal conductivity, High-conductivity, high-strength high-performance carbon foam

Images