Polytetrafluoroethylene waterproof gas-permeable membrane and preparation method thereof

Abstract

The invention discloses a polytetrafluoroethylene waterproof gas-permeable membrane and a preparation method thereof, and relates to a polytetrafluoroethylene waterproof gas-permeable membrane which is suitable for a gas sensor and has good gas permeability and hydrophobic property, and a preparation method thereof. The invention relates to the polytetrafluoroethylene waterproof breathable membrane which is prepared by the steps: uniformly mixing a polytetrafluoroethylene emulsion base material, pore-forming filler zinc oxide and aluminum oxide, and cross-linking dispersing auxiliary agents anhydrous sodium sulfate and sodium chloride, and carrying out mould pressing sintering and turning processing to obtain a membrane base material; the membrane base material is prepared through the procedures of pore forming agent removal, drying, hydrophobic treatment and irradiation; and the weight ratio of the polytetrafluoroethylene emulsion base material to the pore-forming agent filler zinc oxide to the pore-forming agent filler aluminum oxide to the crosslinking dispersing auxiliary agent anhydrous sodium sulfate to the crosslinking dispersing auxiliary agent sodium chloride is (40%-80%):(10%-40%):(10%-40%):(2%-10%). The problem that the sensitivity of a gas sensor is too high due to the fact that the ventilation volume of an existing waterproof breathable membrane cannot be controlled is solved, and the gas sensor can be sealed more easily.

Description

technical field [0001] The invention relates to a polytetrafluoroethylene waterproof and gas-permeable film suitable for gas sensors with good air permeability and hydrophobic properties and a preparation method thereof. Background technique [0002] As we all know, a gas sensor is a converter that converts a certain gas volume fraction into a corresponding electrical signal. [0003] Depending on its type, the gas sensor either uses the change in the resistance of the semiconductor when it contacts the gas to detect the composition or concentration of the gas, or uses the electrochemical reaction that occurs when the working electrode of the sensor contacts the gas to cause it to flow through the external circuit. The current to detect the composition or concentration of the gas. Gas sensors need to be equipped with waterproof and breathable membrane materials with good chemical stability. [0004] This kind of membrane material has hydrophobic characteristics, so that th...

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Problems solved by technology

[0005] The air permeability of the existing waterproof and breathable membrane is too high. For gas sensors, the use of this waterproof and breathable membrane will lead to too high sensitivity of the gas sensor, making the measurement results of the gas sensor inaccurate

[0006] Moreover, the strength of the existing waterproof and breathable membrane is not high, and it can only be stretched in one direction. When the waterproof and breathable membrane is pressed to the gas sensor, the gas sensor cannot be completely sealed or damaged in the non-extensible direction.

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