Powdery thermoplastic polyimide with low glass transition temperature, and preparation method thereof

Abstract

The invention relates to a powdery thermoplastic polyimide having a low glass transition temperature, and a preparation method thereof. The glass transition temperature of the thermoplastic polyimideis 220-250 DEG C, and the average particle size is 5-20 [mu]m. The introduction of a specific siloxane group into the molecular structure can reduce the slight crosslinking phenomenon of a polyimide molecular chain at a high temperature and realize excellent thermal stability and mechanical properties after molding, so the glass transition temperature of the polyimide glass is lowered, thereby theprocessing temperature is lowered, the production efficiency is increased, the production cost is reduced, and the safety index in the production process is improved.

Description

technical field [0001] The invention relates to the field of polyimide polymer materials, in particular to a powdery thermoplastic polyimide with a low glass transition temperature and a preparation method thereof. Background technique [0002] Polyimide (PI) is a class of polymers containing cyclic imide groups in the molecular chain. Polyimide has attracted much attention because of its excellent high temperature resistance, low temperature resistance, high strength, high creep resistance, high dimensional stability, high electrical insulation, low dielectric constant and low loss, and corrosion resistance. It is known as "" One of the most promising engineering plastics in the 21st century". In view of its excellent performance, it is also considered a "problem-solving expert". However, because polyimide cannot be dissolved in common organic solvents and cannot be melt-processed under heating, its wide application is limited. [0003] In this regard, researchers have r...

AI Technical Summary

Problems solved by technology

However, the introduction of flexible groups will destroy the thermal stability and mechanical properties of polyimide, and the synthesis of monomers with large side groups or asymmetric structures is difficult and cannot be applied on a large scale.

In addition, traditional thermoplastic polyimides also have problems to be solved, such as high glass transition temperature, processing thermoplastic polyimide requires a high reaction temperature, the temperature range is generally 300 ~ 425 ° C

Processing thermoplastic polyimide at this temperature, in addition to high production costs, operators are often exposed to potentially dangerous situations during the production process, resulting in many safety hazards

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