The conventional biaxially stretched PTFE film has poor uniformity and large pore size distribution. Therefore, a preparation method of a PTFE film having a pore diameter of less than 0.1 μm is proposed, and the two layers of polytetrafluoroethylene tape are simultaneously degreased and then co-pulled. Stretching and co-curing, through the regulation of process parameters such as degreasing tension and temperature, the multi-layer welding is firm, and the nano-aperture PTFE composite membrane is developed, which lays a foundation for the protection of radioactive dust.
In the PTFE structure and film morphology of the degreased, there is no gap between the two base tapes and the PTFE film, and the bond is good; and there is a transition layer, the fibril length is shorter than other parts, and the combination density is large, showing obvious Asymmetric structure. Due to the cross-over coverage between the fibrils, the pore size and void ratio are reduced while the pore size distribution is narrowed. The average pore size and porosity of the two-layer film are significantly lower than those of the single-layer PTFE film under the same conditions.
Experts studied the perspective of expanded PTFE membranes and the protective principle of PTFE nanoporous membranes for airborne particulates, chemical poisons, chemical poisons, aerosols, etc., and proposed multi-functional protective fabric layers and protection for the first time in China. The concept of a three-in-one nuclear biochemical protection system for barrier and adsorption layers. The protective barrier layer is made of a super-hydrophobic modified nano-porosity polytetrafluoroethylene selectively permeable membrane, and the multi-functional fabric layer is made of a flame-retardant fiber and an anti-static fiber blend fabric, and is multifunctionalized by dyeing, printing, multi-functional finishing, and the like. The polytetrafluoroethylene nanoporous membrane and the multifunctional fabric layer are combined to form a multifunctional protective barrier layer, and the activated carbon fiber is used as an adsorption layer to adsorb a small amount of toxic gas through adsorption to achieve protection against harmful gases. This combination of active protection and passive protection can effectively prevent nuclear and biochemical hazards through killing, blocking and adsorption. It also has antibacterial sterilization, flame retardant, antistatic, camouflage, and oil repellent. Water-repellent, waterproof, moisture-permeable and other functions.