Precautions for using PTFE sheets?

Notes on the use of PTFE sheet? I believe that many friends are still not clear, in order to enhance your understanding, the following is a specific introduction to this issue, interested in a look! If you are also interested, you may want to check here.

Polytetrafluoroethylene sheet is also a popular product now. But many people do not understand its role. The first thing we need to know is that the use of polytetrafluoroethylene plate is due to its low heat transfer coefficient, poor heat transfer performance, not only can not be used as bearing materials, but also in the production of thick-walled tubing products to avoid heat treatment. There is also the coefficient of thermal expansion is 10 to 20 times that of steel, which is greater than most plastics, and the coefficient of thermal expansion varies unevenly with temperature. When using PTFE, it is easy to destroy these properties if you don't pay attention to them. Of course, it has a special non-stick, which limits its industrial applications. It has “cold flow”. That is, the plastic deformation (stress relaxation) of the material product under the action of continuous load for a long period of time, which, of course, imposes certain limitations on its use. For example, when PTFE plates are used as sealing gaskets, the foot bolts are tightened very tightly to make a tight seal, so that when the extra tension is exceeded, the seal is flattened by “cold flow” (stress relaxation). These defects can be corrected by adding suitable packing and improving the construction of the part.

When PTFE sheet is heated above 400°C, its cracking rate gradually accelerates and the dissolved substances are mainly tetrafluoroethylene, perfluoro and octafluorocyclobutane. Above 475. a small amount of solute is toxic. Therefore, it should be noted that its heating temperature should not exceed 400 degrees, and the laboratory should have a good exhaust system to help remove toxic gases. Of course due to its high melt viscosity, it does not flow at high temperatures. Polytetrafluoroethylene sheet above the melting point (327 ° C), the solution viscosity reaches 1010 Pa.s, even when heated to the melting point has no mobility, which makes it can not be used in the usual thermosetting plastic molding methods, but we use a similar powder metallurgy. Such calcination is produced. And its outstanding non-stick properties limit its industrial application. The superior anti-adhesive material makes it difficult to stick to the surface of other objects. Polytetrafluoroethylene sheets, especially above 475. contain small amounts of highly toxic isobutylene in the decomposition products. Therefore, it should be taken into account that the heating temperature of PTFE sheet gaskets should not exceed 400 degrees, and the laboratory should have a good ventilation system to help exclude toxic gases.