Method for preparing polyimide film with surface modified by MWNTs (multi-walled carbon nanotubes)

Abstract

The invention relates to the technical field of polyimide films and in particular to a method for preparing a polyimide film with a surface modified by MWNTs (multi-walled carbon nanotubes). The method comprises the following steps: drying raw materials, pretreating MWNTs, performing MWNTs surface treatment, preparing a MWNTs / PAA (polyacrylic acid) hybridization liquid, and performing film formation. As pretreatment is implemented on MWNTs through ultrasonic waves, a cavatition action and a partial high-temperature high-pressure function formed by the cavatition function act on the MWNTs, theintermolecular force of the MWNTs can be damaged, the MWNTs which are tangled together before can be loosened and opened, double bonds on surfaces of the MWNTs are subjected to oxidation attack by afree radical OH* generated by a Fenton's reagent, a hydroxyl group is grafted on the surfaces of the MWNTs, the compatibility of the MWNTs with a substrate can be improved, the imidization degree of the film can be prevented from being reduced, and structures of the MWNTs can be kept complete; and the dielectric constant of the polyimide film with the surface modified by the MWNTs is kept identical to that of a pure PI (polyimide) film, and meanwhile, the tensile strength and the dielectric strength can be remarkably improved.

Description

technical field [0001] The invention relates to the technical field of polyimide membrane preparation, in particular to a method for preparing a polyimide membrane with surface-modified MWNTs. Background technique [0002] Polyimide (Polyimide, referred to as PI) refers to a class of polymers containing imide rings on the main chain, among which the structure of phthalimide is the most important. The chemical structure of polyimide is as follows: [0003] [0004] The English name of polyimide film is polyimidefilm, PI film (referred to as PI film, PI film). It is one of the organic polymer materials with the best comprehensive performance. Excellent comprehensive properties such as radiation resistance and corrosion resistance. As a functional polymer material, polyimide film is widely used in the insulating layer of flexible printed circuit boards and VLSIs. With the demand for high-density development of integrated circuits in the electronic field, the performance of ...

AI Technical Summary

Problems solved by technology

[0005] Inorganic materials filled with modified polymers are relatively common, but most of them are to reduce production costs and cannot improve the performance of composite materials well. With the development of fine preparation of inorganic particles, the emergence of nanoparticles has brought new opportunities for research in the field of composite materials. new opportunity

As a one-dimensional long-fiber nanomaterial, MWNTs not only have the typical mechanically enhanced structure of inorganic fiber materials, but also have the surface effect of nanomaterials. However, the surface of MWNTs with graphene sheet curl structure is smooth and does not have the ability to form effective bonds with PI molecules. Therefore, it is difficult to maintain a good dispersion in the PI matrix with a long fiber structure without entanglement, so it is particularly important to study the surface treatment of MWNTs

There are many surface treatment methods for MWNTs, and each treatment method has different treatment effects on MWNTs. However, most surface-treated nanoparticles not only improve the corona resistance and breakdown resistance of PI films, but also make PI films The tensile strength of the film is reduced, which is very unfavorable for the practical application of PI films. Whether a surface treatment method for MWNTs can be found that takes into account the mechanical properties and electrical properties of PI films is of great significance to the practical application of PI films.

Images