Preparation method of enhanced hollow polyvinylidene fluoride fiber membrane

Abstract

The invention discloses a preparation method of an enhanced hollow polyvinylidene fluoride fiber membrane. The preparation method comprises the following steps: (1) preparation of an enhanceosome: braiding polyacrylonitrile fiber into a hollow braided pipe by adopting a two-dimensional braiding technology; (2) preparation of separation layer casting film liquor: respectively dissolving 5-25wt% polyvinylidene fluoride resin and 5-30wt% of additive into a solvent, stirring and dissolving under the condition of 70-90 DEG C, conducting vacuum defoaming to obtain the separation layer casting film liquor; (3) surface pretreatment of the enhanceosome: cleaning and drying the enhanceosome with a neutral detergent, and then infiltrating the enhanceosome with slight polar organic liquid; and (4) preparation of the enhanced hollow polyvinylidene fluoride fiber membrane: evenly coating the separation layer casting film liquor obtained from the step (2) on the surface of the enhanceosome treated in the step (3), and curing to obtain the enhanced hollow polyvinylidene fluoride fiber membrane. The binding strength of a separation layer on the surface of the enhanced hollow polyvinylidene fluoride fiber membrane prepared by adopting the method and the enhanceosome is high, and the separation layer and the enhanceosome are unlikely to strip, and high-pressure backflushing can be conducted.

Description

technical field [0001] The invention relates to the field of membrane technology, in particular to a method for preparing a reinforced polyvinylidene fluoride hollow fiber membrane. Background technique [0002] Polyvinylidene fluoride has strong anti-pollution, good anti-ultraviolet and weathering resistance, good mold resistance, high impact strength and abrasion resistance, good chemical stability (not easy to be corroded by acid, alkali, halogen or strong oxidant, etc. ) and other advantages, has been widely used in the field of film production. However, the strength of the polyvinylidene fluoride hollow fiber membrane prepared by the solution spinning method is low, and it is impacted by high-pressure water flow for a long time during use. Component life is reduced, productivity is reduced, and production costs are increased. [0003] At present, there are two methods for preparing reinforced polyvinylidene fluoride hollow fiber membranes: [0004] One is the prepara...

AI Technical Summary

Problems solved by technology

This type of coating method simply coats the casting liquid on the surface of the fiber braided tube, because the fiber braided tube and the polymer separation membrane are two materials with different interface properties, and the bonding ability between the two materials is limited (such as Polyvinylidene fluoride separation membrane and polyester fiber braided tube), when the hollow fiber membrane is used in a high-strength vibration environment or frequently backwashed, peeling between the polyvinylidene fluoride coating layer and the polyester fiber braided tube is prone to occur , causing structural damage to the surface of the membrane and affecting the quality of the effluent

[0009] The problems in the above technical solutions are: the homogeneously reinforced polyvinylidene fluoride hollow fiber membrane, the entire production process is complicated to control, and the manufacturing cost is high; usually the heterogeneously reinforced polyvinylidene fluoride hollow fiber membrane, the reinforcement material used is Polyester, polyamide, and surface separation layer material polyvinylidene fluoride are not only different types of materials, but also non-co-solvent soluble polymer materials. There are differences in compatibility. During the backwashing process, the surface separation layer is prone to damage or peeling off from the surface of the reinforcement, seriously affecting the service life of the membrane