Method for preparing polyimide in supercritical carbon dioxide

Abstract

The invention relates to a method for preparing polyimide by performing polymerization reaction in supercritical carbon dioxide, belongs to the technical field of synthesis of polyimide polymer, and solves the technical problems that an organic solvent is needed and subsequent treatment difficulty is high in the synthesis reaction process of the polyimide in the prior art. According to the method, the polyimide is synthesized by taking acid anhydride or aniline as a blocking agent and the supercritical carbon dioxide as a medium. The method comprises the following steps of: adding dianhydride, a diamine monomer, a catalyst and the blocking agent into a reaction kettle at one time or in batches, introducing carbon dioxide, and gradually raising temperature and pressure to ensure that a system is in a supercritical state; and polymerizing at certain temperature and pressure to obtain a polyimide product with a good shape and high performance. The organic solvent is not used, the product is pure, subsequent treatment is not needed, the reaction medium is non-toxic and pollution-free, and the method is an economic, practical and environment-friendly process method for synthesizing and preparing the polyimide.

Description

technical field

[0001] The invention belongs to the fields of chemical industry and polymer materials, and relates to a method for preparing polyimide in supercritical carbon dioxide. Background technique

[0002] Polyimide (PI) refers to a class of polymers containing imide rings on the main chain.

[0003]

[0004] Polyimide is a high temperature-resistant polymer material that can withstand high temperatures of 500°C for a short time and can be used for a long time below 300°C. As a cutting-edge material with outstanding performance, it is widely used in electromechanical, electronic and electrical, instrumentation, petrochemical, measurement and other fields with its excellent electrical insulation, wear resistance, high temperature radiation resistance and physical and mechanical properties, and has become a global rocket One of the indispensable materials in cutting-edge technology fields such as aerospace, aerospace, etc. However, its output and consumption are re...

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