| [Visitor (112.0.*.*)]answers [Chinese ] | Time :2022-05-09 |  The material that makes this coating. In thick film integrated circuits, the film refers to the thickness of the film layer of about 1 μm, and the thick film refers to the thickness of the film layer of 10 to 25 μm. In the printed circuit, a film with a thickness greater than 0.1mm is referred to. For example, PET thick film refers to 120μm-3000μm polyester film. |
| [Visitor (112.0.*.*)]answers [Chinese ] | Time :2022-05-09 |  Dense film
The pore structure of the membrane is difficult to distinguish with electron microscopy, and its model can only be determined by gas permeation and liquid permeation or gas adsorption.
The preparation of dense film is: solvent casting method, which forms a dense film after the solvent is completely evaporated, the method of removing the solvent has a profound impact on the permeability of the film, melt extrusion method, membrane structure and performance depend on the molecular internal force, the rigidity of the chain, molecular weight and disproportionation, but also depends on the various dynamic factors contained in quenching and annealing.
The dense film formed during polymerization is caused by crosslinking in interfacial polycondensation, such as the FT-30 composite film formed by the interface of m-phenylenediamine and homophthalyl chloride.
The surface active layer of asymmetric film and composite film with permeability and separation performance belongs to the dense film, and its thickness is inversely proportional to the amount of transmission. Reducing the thickness of dense films is the most effective way to improve the economic benefits of membrane separation technology. Therefore, the development of composite membranes has received more and more attention.
In order to reduce the permeation resistance, the film is generally made very thin (0.5 ~ 500μm), called ultra-thin film.
Non-porous films include metal, glass and other inorganic films, as well as polymer films.
Non-porous membranes can be made into flat and hollow fibers. |
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