Preparation method of colorless transparent polyimide film with low yellowness and high mechanical property

Abstract

The invention relates to the field of high polymer materials, and discloses a preparation method of a colorless transparent polyimide film with low yellowness and high mechanical property. Aminated nanocellulose and carboxylated nanocellulose are introduced into a full-fat ring type polyimide film; the aminated nanocellulose and the carboxylated nanocellulose respectively serve as diamine monomers and end-capping reagents, can participate in the reaction of alicyclic diamine and alicyclic dianhydride and are doped into a polyimide polymer main chain in a covalent bond form, the stability is good, the mechanical property and the heat resistance of the polyimide film can be improved, and the polyimide film can be used as a polyimide film. The high-temperature yellowing effect caused by amino groups on diamine can also be inhibited. The finally prepared polyimide film still has relatively high mechanical and heat-resistant properties while the light transmittance is greater than 90%.

Description

technical field [0001] The invention relates to the field of polymer materials, in particular to a preparation method of a colorless and transparent polyimide film with low yellowness and high mechanical properties. Background technique [0002] Polyimide is a kind of high molecular polymer containing imide units in the main chain. It has excellent heat resistance, mechanical properties, chemical stability and dielectric properties, so it is widely used in aerospace, semiconductor packaging, Solar cells and other fields. [0003] In recent years, the vigorous development of flexible display products, especially flexible mobile phones and flexible wearable devices, has put forward higher requirements for the bendability of materials. Traditional glass substrates have been difficult to meet the requirements, and polyimide films have excellent durability. Thermal and mechanical properties, which have attracted more and more attention, are regarded as one of the best materials ...

AI Technical Summary

Problems solved by technology

In the above-mentioned patents, the mechanical properties of the film are improved by introducing cellulose into the polyimide material, but in this solution, the cellulose is loaded in nano-alumina, and the cellulose is only dispersed in the polyimide by physical blending. In the imine substrate, due to the limitation of compatibility, the stability is poor, and it is easy to precipitate after aging in the later stage, and this method is not suitable for adding a large amount of cellulose

[0006] In addition, the traditional methods of reducing the yellowness of polyimide films are mainly accomplished by adding fluorine-containing monomers, introducing bulky substituents, main chain bending structures, asymmetric structures, and reducing conjugated double bond structures. It is mainly to reduce the intramolecular or intermolecular charge transfer, thereby reducing the formation of electron transfer complexes (CTCs) and improving the light transmittance and transparency of polyimide films, but these methods have no effect on the amino groups formed by diamine residues. Insufficient attention is paid to the yellowing caused by high temperature

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