Performance and manufacturing process of polymer separation membrane

Polymer membrane uses external energy or position difference as the driving force to separate, classify, purify and enrich the solutes and solvents of two-component or multi-component solutions. The method of collection is generally called membrane separation method. The membrane separation method can use F aqueous solution system, non-aqueous solution system, hydrosol system and aqueous solution system containing other particles.

The membrane should have two obvious characteristics: first, the membrane must have two interfaces through which it is in contact with the fluid on both sides; second, the membrane must have It has selective permeability, which allows one or several substances in the fluid phase to pass through, but does not allow other substances to pass through.

To achieve membrane separation of substances, energy must be used as a driving force. Due to the different forms of energy given, membrane separation has different names, as shown in Table 3 -4 shown.

The manufacturing process of the membrane has a great influence on the performance of the membrane. Even if it is the same membrane material, due to the use of different membrane processes and process parameters, the performance of the membrane will be different. Membrane performance can vary significantly. Using physical or chemical methods or a combination of both methods, polymer membranes with good analytical properties can be made. Chemical methods such as polymerization, copolymerization, graft copolymerization, block copolymerization, plasma surface polymerization, surface modification, interfacial polycondensation, polymer chemical reaction or radiation cross-linking, blending and fusion of polymers, and addition of fillers in polymers Various methods such as re-dissolution and surface coating of polymers with functional groups can be used to obtain high separation performance

Table 3-4 The driving force and membrane technology names of abdominal separation

Ren membrane. From a physical point of view, the film-forming process adopts casting method, scraping method, impregnation method, glue dipping method, spinning method, cutting method, biphasic stretching method and other methods to form a film. If the mentioned methods are Used together, various membrane materials such as heterogeneous membranes, homogeneous membranes, semi-homogeneous membranes, and composite membranes can be produced.

There are many polymer materials used for film making, which can be roughly divided into the following categories: such as modified cellulose, polyaramid, and nylon. .Poly inkstone, polyacrylic acid and its esters, polyvinyl alcohol and its acetals, polyethylene, polypropylene, polystyrene, polysulfuric acid, polyethylene oxide and various commercial polymer materials and their mixture.