Hydrophobic porous composite membrane, preparation method, and application thereof

Abstract

The present invention discloses a hydrophobic porous composite membrane, a preparation method, and an application thereof. According to the present invention, the substrate of the hydrophobic porous composite membrane is a hydrophobic porous membrane; a layer of a copolymer is compounded on the surface of the hydrophobic porous membrane; the copolymer is a random copolymer or a block copolymer, the hydrophobic end of the copolymer is polymethacrylic acid-2-ethyl cinnamate or polyacrylic acid-2-ethyl cinnamate, the hydrophilic end of the copolymer is one selected from polymethyl methacrylate, polymethyl acrylate, polyacrylamide, polyvinylpyrrolidone, polyacrylonitrile or polyglyceryl methacrylate. According to the present invention, with the method for the hydrophilic modification of the hydrophobic porous membrane, the hydrophilicity of the hydrophobic membrane is effectively improved; the hydrophobic porous membrane and the copolymer are subjected to cross-linking coupling, such that the prepared composite membrane has characteristics of good use stability and long aging; with the hydrophobic porous composite membrane of the present invention, defects of insufficient wettability of the hydrophobic membrane and low liquid absorption rate of the membrane in the existing lithium battery are overcome.

Description

technical field [0001] The invention belongs to the field of materials, and in particular relates to a hydrophobic porous composite membrane and its preparation method and application. Background technique [0002] In a typical membrane separation process, there are two distinct requirements, both high permeability and high selectivity. For a single polymer film, it is difficult to meet the above two requirements at the same time. Although theoretically speaking, the polymer materials used to make membranes are quite extensive, the polymer materials actually used for separation membranes are very limited. In addition to processing reasons, the main reason is that for a specific separation system, it needs Membrane materials with specific properties. For example, membrane materials for separating aqueous systems require an appropriate hydrophilic / hydrophobic balance to obtain high permeability and selectivity. This puts strict requirements on the selection of membrane mate...

AI Technical Summary

Problems solved by technology

[0005] At present, the methods for hydrophilic modification of hydrophobic membranes include the surface coating hydrophilic polymer method. CN1153867C discloses a hydrophobic polymer uniformly coated with hydrophilic polymer materials to form a coating porous substrate, but hydrophilic The interaction between water-based polymers and hydrophobic polymers is not ideal, and hydrophilic polymers are easy to fall off during use

[0006] Surface grafting hydrophilic polymer method, CN100366666C discloses a method for hydrophilic modification of polyvinylidene fluoride membrane, the method combines blending and surface grafting technology, first PVDF with another photosensitive polymer Microporous membranes or dense membranes are prepared from materials, and then hydrophilic monomers are grafted on the surface of the blended membranes by surface grafting method, but the process is complicated and the grafting reaction conditions are harsh.

[0007] Blending method with hydrophilic polymer, CN101773789A discloses a method for preparing a hydrophilic membrane material, which forms a film after being prepared into a uniform solution from an amorphous polymer and a hydrophilic polymer, and the two polymers are entangled with each other, but Without cross-linking, the membrane material may undergo phase separation, and the amount of hydrophilic polymer is large

[0008] Surfactant treatment method, JP63-277251 discloses a method for modifying a hydrophobic porous membrane, using a surfactant to coat the surface of a porous hydrophobic polysulfone-based membrane to improve its hydrophilicity; but the timeliness is not long, Surfactant peels off easily

[0009] Wet storage method, in order to avoid the complete drying of the membrane and maintain the activity of the membrane, wet storage of the membrane is also a method to maintain the hydrophilicity of the membrane, but once the wet membrane is dried, shrinkage and deformation will occur due to dehydration, making the membrane pores Substantial shrinkage, or damage to the membrane structure, while making the texture of the membrane brittle