▎ 摘　　要

NOVELTY - Continuous preparation of polyvinylidene fluoride hollow fiber film involves preparing a film-forming system using a composition of raw materials comprising 40-60 wt.% polyvinylidene fluoride, 10-30 wt.% rigid polymer with poor compatibility with polyvinylidene fluoride, decomposition temperature higher than the melt spinning temperature and glass transition temperature higher than the stretching temperature as an organic additive and nanomaterial with a two-dimensional lamellar structure, as inorganic additive, 10-30 wt.% water-soluble polyethylene oxide as pore-forming agent, preparing hollow fiber film by using a twin-screw extruder to melt-spin the film-forming system through a hollow spinneret, after the spinning melt is solidified, drawing into a hot drawing machine for continuous stretching to form interfacial pores, and winding and collecting hollow fiber membrane and soaking the hollow fiber membrane in water, shaking and washing to remove the pore-forming agent. USE - Continuous preparation of polyvinylidene fluoride hollow fiber film used for textile, material, chemical engineering, and environmental applications. ADVANTAGE - The method adopts the continuous stretching method of melt spinning to make film, and utilizes the poor compatibility characteristics of polyvinylidene fluoride and composite additives to generate multiple interface holes through stretching, to improve the permeability of the film, and can realize continuous large-scale preparation of polyvinylidene fluoride hollow fiber film. The film-making process does not need to use any organic solvent and thinner, so it is green and environmentally-friendly. DETAILED DESCRIPTION - Continuous preparation of polyvinylidene fluoride hollow fiber film involves (1) preparing a film-forming system by fully dissolving a pore-forming agent in water to form an aqueous solution, and adding inorganic additives to the aqueous solution to disperse it evenly to obtain a mixture liquid, (ii) fully drying the mixture liquid in a vacuum oven to obtain a mixture, (iii) uniformly mixing polyvinylidene fluoride, organic additives and the mixture and granulating by a high-speed pulverizer to obtain a film-forming system, (2) preparing hollow fiber film by using a twin-screw extruder to melt-spin the film-forming system obtained in step (1) through a hollow spinneret at a spinning temperature of 180-260℃, after the spinning melt is solidified, drawing into a hot drawing machine for continuous stretching to form interfacial pores, at the stretching ratio of 0.5-5, and winding and collecting hollow fiber membrane and (3) soaking the hollow fiber membrane in water, shaking and washing to remove the pore-forming agent. The composition of raw materials for the film-forming system comprises 40-60 wt.% polyvinylidene fluoride, 10-30 wt.% organic and inorganic additives, 10-30 wt.% pore-forming agent. The organic additive is a rigid polymer with poor compatibility with polyvinylidene fluoride, a decomposition temperature higher than the melt spinning temperature and a glass transition temperature higher than the stretching temperature. The inorganic additive is a nano-material with a two-dimensional lamellar structure. The pore-forming agent is water-soluble polyethylene oxide.