Microcellular foaming polyimide based electromagnetic shielding composite material and preparation method thereof

Abstract

The invention discloses a microcellular foaming polyimide based electromagnetic shielding composite material. A preparation method of the microcellular foaming polyimide based electromagnetic shielding composite material comprises the following steps: firstly, carrying out surface etching treatment on a CNT (Carbon Nanotube) by adopting a hydrothermal high-temperature and high-pressure method and using sodium hydroxide; secondly, synthesizing a polyamic acid solution by taking pyromellitic dianhydride and 4,4'-diaminodiphenyl ether as raw materials, dispersing and mixing the polyamic acid solution with the CNT after the surface etching treatment, uniformly coating the surface of the CNT with the polyamic acid solution through ball milling-stirring treatment under a room temperature, and then carrying out microcellular foaming treatment by adopting a phase separation method after solidifying a mixed solution; finally, carrying out thermal imidization, thus obtaining the electromagnetic shielding composite material. In the preparation method disclosed by the invention, the CNT after the surface etching treatment is uniformly dispersed in a polyimide material through ball milling-stirring technological treatment, and a conductive network can be favorably formed in a polyimide-based material by the CNT, so that the electromagnetic shielding effectiveness can be effectively increased.

Description

technical field [0001] The invention relates to the field of polyimide materials, in particular to a microporous foamed polyimide-based electromagnetic shielding composite material and a preparation method thereof. Background technique [0002] Due to the increasingly serious electromagnetic pollution, in order to limit and protect electromagnetic waves to the greatest extent, the development of materials with excellent shielding ability is particularly important. At present, the most used shielding materials are metal materials. Metal materials are difficult to form, heavy in weight, and expensive. There are great limitations when used as shielding materials. [0003] Carbon nanotubes (CNTs) have excellent mechanical and electromagnetic properties. The unique one-dimensional hollow tubular structure makes it have a large aspect ratio. As a wave-absorbing material, it has light weight, good electrical properties, and a wide wave-absorbing frequency band. Etc. Carbon nanotu...

AI Technical Summary

Problems solved by technology

At present, the most used shielding materials are metal materials. Metal materials are difficult to form, heavy in weight, and expensive. There are great limitations when used as shielding materials.