Polyvinylidene fluoride hollow fiber membrane and preparation method thereof

Abstract

The invention relates to a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof, belonging to the field of chemical industry. The pore size of the membrane is 0.02-0.5 micrometers, the thickness is 0.2-0.5 millimeters, and the external diameter of membrane wires is 1-2 millimeters. A membrane making liquid comprises the following components in percentage by weight: 15-30% of polyvinylidene fluoride resin, 1-10% of hydrophilic polymer, 0.5-5% of functional polymer or polymer monomer, 0.1-5% of surfactant, 0.1-15% of inorganic or organic polymer pore-forming agent, 0.1-5% of nano additive and 40-71% of solvent. The preparation method of the polyvinylidene fluoride hollow fiber membrane comprises the following step of: effectively controlling the interfacial tension between the membrane making liquid and a solidifying liquid and the double diffusion permeation speed of the solidifying agent and the solution on the interface by properly adjusting the ratio of all components and using the surface moistening and dispersing actions of the surfactant, the dispersing and thickening actions of the pore-forming agent and the hydrophilic action of the hydrophilic substance. Thus, the hydrophilic polyvinylidene fluoride hollow fiber membrane with high permeability is prepared.

Description

technical field [0001] The invention relates to a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof, belonging to the technical field of chemical product processing methods. Background technique [0002] Polyvinylidene fluoride hollow fiber membrane is a new generation of porous membrane that has appeared in recent years. Compared with other porous membranes, it has many unique and excellent properties: good heat resistance, long-term use temperature can reach 150 ° C; UV, γ-ray radiation resistance ; Strong acid and alkali resistance, long-term use range PH1-12 at room temperature; resistance to organic solvents, such as strong oxidants, aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, alcohols, aldehydes, etc. It is suitable for film production by dry-wet method or wet spinning method, and is easy to manufacture and low in cost. Therefore, it has great application value and wide application fields. However, polyvinylid...

AI Technical Summary

Problems solved by technology

However, polyvinylidene fluoride resin has the characteristics of low surface energy and strong hydrophobicity. It has the following disadvantages when used as a water treatment membrane: first, it is easy to produce adsorption pollution (especially when it contains protein solutions), and the penetration of the membrane The main separation indicators such as the amount and rejection rate will be significantly reduced, which will shorten the actual service life of the membrane; the second is that the separation process requires a large driving force

However, the surface modification of the membrane often changes the pore size and pore size distribution of the membrane surface to a certain extent. The physical adsorption method only makes the hydrophilic polymer adsorb on the surface or inside of the membrane through physical adsorption. The water agent is very easy to lose, causing the hydrophilicity to not be maintained for a long time

Chemical modification often affects the strength of the separation membrane to a certain extent, and the treatment conditions are relatively harsh, and if the hydrophilic modification is too large, the membrane is easy to dissolve