Preparation method of partial fluorothene copolymer microporous membrane

Abstract

The invention is a method of preparing vinylidene fluoride (VDF) copolymer microporous membrane, dissolving pore-making agent in the organic solvent to prepare the pore-making agent solution, then adding in VDF to make into film casting solution, filtering and eliminating impurities and gel in the film casting solution, then defoaming at the dissolving temperature, until there is no bubble in the film casting solution, scratching the film casting solution on a smooth carrier, where during film making course, the temperature is 20-50 deg.C and the humidity is 15-75%, after scratching, volatilizing for 10-300 seconds, placing the plate together with the film-casting solution in the 10-60 deg.C coagulating liquid to solidify the film casting solution into a film which naturally floats, thus producing a primary film, placing the primary film in the water to rinse for 4-8 hours, and drying the primary film in turn at the rinsing room temperature by rinsing liquid to obtain the object product. And at last it applies the object product to film distillation and relative film courses.

Description

technical field [0001] The invention relates to the preparation of a hydrophobic microporous membrane. Specifically, it relates to the preparation of a vinylidene fluoride copolymer microporous membrane used in membrane distillation and related membrane processes. Background technique [0002] Among the hydrophobic membrane materials that have been developed at present, although polytetrafluoroethylene and polypropylene have good hydrophobicity, because it is difficult to find a suitable solvent to dissolve, they can only be prepared by stretching (M.Tomaszewska, J.Membr .Sci., 78(1993) 277; N.Chlubek and M.Tomaszewska, Env.Prot.Eng.15(1989) 95), not only the process is complicated, it is difficult to realize in the general laboratory, and the porosity of the obtained membrane is relatively low . Polyvinylidene fluoride can be dissolved in strong polar solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone, and is the most successful example of usin...

AI Technical Summary

Problems solved by technology

In the actual operation process, the inevitable mechanical vibration may cause damage to the microporous membrane, thereby affecting the life of the membrane module. Therefore, better mechanical strength is also a necessary consideration for the selection of membrane materials; although polyvinylidene fluoride has good Hydrophobic, but its poor mechanical properties may limit its use in some processes or environments. On the other hand, from the data of contact angle with water (commonly used to characterize the hydrophobicity of materials), poly The hydrophobicity of vinyl fluoride is not very ideal, there is still room for improvement