Polytetrafluoroethylene ultrafine fiber membrane

Abstract

The invention provides a polytetrafluoroethylene ultrafine fiber membrane which comprises a polytetrafluoroethylene material body, wherein the polytetrafluoroethylene is fibrous with the fiber diameter of 30-200nm; the body has pore cavities with the pore size of 10-1000nm and cavity walls formed around the pore cavities in the three-dimensional space, and the pore cavities are uniformly distributed and are respectively perforated in the three-dimensional space; and the uniform distribution of the pore cavities refers to uniform distribution of the pore cavities in the porous material in any unit level of volume. The porosity is greater than or equal to 75%, the tensile strength is 15 N / mm<2> or above, and the water pressure resistance is 3kg / cm<2> or above. The invention provides a specific and definite measurement mode for uniform distribution of pore cavities of the polytetrafluoroethylene fiber membrane, and determines that the pore distribution uniformity of the porous material and multilevel structure thereof is measured by the small unit level of volume, so the porous structure is highly uniform, thereby ensuring the uniformity of various properties of the porous material.

Description

technical field [0001] The invention relates to a porous material, in particular to a polytetrafluoroethylene fiber membrane, which is especially suitable for membrane distillation. Background technique [0002] A solid with a certain number of pores is called a porous material, which is a material with a network structure composed of through or closed pores. Compared with continuum materials, porous materials generally have the advantages of low relative density, high specific strength, high specific surface area, light weight, sound insulation, heat insulation, and good permeability. According to the different pore sizes, porous materials can be divided into microporous (pore diameter less than 2 nm) materials, mesoporous (pore diameter 2-50 nm) materials and macroporous (pore diameter greater than 50 nm) materials. [0003] Porous materials can be divided into metal porous materials and non-metal porous materials according to their materials. Non-metallic porous materia...

AI Technical Summary

Problems solved by technology

However, due to the randomness and irregularity of the pore structure, it still cannot meet the performance requirements of many applications.

[0004] In many applications, it is required that the porous material itself is uniform, the pore size and the distribution of the pores are uniform, so that the performance is uniform, but in fact, many porous materials do not meet this requirement, and their uniformity complements; although some materials claim to be Higher uniformity has been achieved, but its uniformity is still the uniformity at the large volume scale. If it is measured with a small volume scale, for example, a plurality of three-dimensional bodies whose volume is not larger than one cubic centimeter are randomly selected on the material, and their volumes are measured respectively. Quality, the difference in uniformity is still very large, so the various properties of PTFE porous membrane materials such as strength, elastic modulus, flux, etc. are not uniform, which seriously affects its function.