Characteristics & Surface Treatment Methods Of PTFE Plastic – Teflon CNC Machining Material

Chemical properties

Polytetrafluoroethylene (PTFE) is the most chemically inert polymer among the known organic compounds. Because of its special molecular structure, it can resist almost all strong acids, strong bases and organic solvents, and even “aqua regia” has nothing to do with it. And it can also maintain this performance under high temperature conditions, so this PTFE CNC machining material is also known as “plastic king”.

The exception is that the alkali metal in the molten state is isolated from oxygen. For example, molten metal sodium can corrode the surface of polytetrafluoroethylene and make the fluorine around the carbon chain react with it. The commonly used method in industry is to use sodium naphthalene solution to modify the surface of polytetrafluoroethylene film or plate under the condition of nitrogen protection or isolation of oxygen, so that the polytetrafluoroethylene on the surface of the film or plate can be defluorinated or oxidized, so that it loses its invisibility and is easy to composite with other materials.

Thermal properties

Polytetrafluoroethylene can show good stability under high temperature conditions. The service temperature is usually – 190 ~ 260 ℃, and the corresponding melting point temperature of this material is 327 ℃. Polytetrafluoroethylene can exhibit good stability under high temperature conditions. The service temperature is usually – 190 ~ 260 ℃. The corresponding melting point temperature of the material is 327 ℃, and the corresponding thermal decomposition temperature is 420 ℃. This is a very high use temperature in the existing engineering plastics. Polytetrafluoroethylene hardly decomposes under the condition of lower than 420 ℃, and can decompose in large quantities only when it exceeds 420 ℃. The total mass loss per hour is about 0.01%, and its decomposition will produce highly toxic substances such as fluorophosgene and perfluoroisobutylene. Therefore, when hot processing polytetrafluoroethylene, it is necessary to avoid the processing temperature higher than 400 ℃ to prevent the formation of certain risk factors. The tensile strength of polytetrafluoroethylene was reduced by about 10% after it was heated at 280 ℃ for 72h. In addition, after using polytetrafluoroethylene at 260 ℃ for a long time, and then transferring it to room temperature, its tensile strength is kept at a predetermined value. Therefore, in terms of thermal decomposition, the material can be used for a short time at 280 ° C and continuously at 260 ° C. In addition, in terms of thermal deformation, the material can be used at 260 ℃ for a long time under the condition of relatively small load. When the load is at a high level, the thermal deformation is very obvious, and the use time is greatly reduced.

Radiation resistance

Polytetrafluoroethylene (PTFE) will undergo a large number of molecular degradation under electron beam. Under the action of high-energy ray, C-C bond and C-F bond are broken at the same time, resulting in the decrease of molecular weight and PTFE performance. In addition, its radiation stability in vacuum environment is obviously better than that in air. This is because under the protection of inert gas in vacuum, in addition to the degradation reaction of PTFE, radiation cross-linking reaction between PTFE molecules will occur. If the proper irradiation temperature and dose are controlled, the treated PTFE material will be translucent, and the radiation resistance, high and low temperature resistance, air permeability and liquid permeability of the material will be greatly improved.