The PTFE material has high corrosion resistance to strong acid, strong alkali and strong oxidant. Even if the temperature is high, it will not work. Its corrosion resistance even exceeds that of glass, ceramic, stainless steel and even gold and platinum.
Expansion coefficient of PTFE material
The PTFE material can be made into high-insulation electrical parts, high-frequency wire and cable sheathing, corrosion-resistant chemical vessels, cold-resistant oil pipelines, artificial organs, and the like. The above is a whole process of inducing nuclear fission. The nucleus becomes unstable and splits into two new nuclei of lower mass. This is the fission reaction of the nucleus. The energy released is called fission energy. When it produces huge energy, it also emits two or three neutrons and other rays. These neutrons hit other uranium cores and caused new nuclear fission. The new fission produced new neutrons and fission energy. As this continued, a chain reaction was formed. The physical properties of PTFE The reactor constructed using the principle of nuclear reaction needs to decelerate the neutrons released during fission, and then cause new nuclear fission. This is due to the equilibrium movement of the neutrons and the thermal motion of the molecules. Neutrons are called thermal neutrons. The electrical insulation properties of PTFE, the reactor in the reactor mainly caused by thermal neutrons is called thermal neutron reactor.
Molding method for PTFE material
The PTFE material compression molding method basically comprises four steps of mixing, pre-forming, sintering and cooling. The preforming is to uniformly add the polytetrafluoroethylene PTFE powder into the mold and pressurize it into a compact preform (ie, a blank) at normal temperature; Sintering is to heat the preform to above the melting point, Cooling is the process of reducing the sintering temperature to room temperature.
Some PTFE is pressed at a temperature above the melting point. This forming mold is called a hot stamping die. The corresponding PTFE mold is called a cold stamping die.
When molding a PTFE material, attention should be paid to the effect of the compression ratio (4-6 for a PTFE) and the molding shrinkage (2.6-4.5% for PTFE).
The raw material is preferably polymerized by a suspension polymerization method, and a soft fine powder having a particle diameter of 20 to 500 μm is preferred. The pressing process must be “deflated”. The preforming pressure is 17-35 MPa. The holding time depends on the thickness of the blank. For example, a blank of 100 mm thickness should be kept at 15 points.