Polytetrafluoroethylene (PTFE) is a homopolymer of tetrafluoroethylene that is widely used as a corrosion-resistant material for equipment, machinery, and pipelines. Its outstanding comprehensive performance and properties are highly beneficial in various applications, such as high-frequency communication equipment, food packaging, textile, and chemical industries.
PTFE has a high level of crystallinity. It is relatively inert against many known elements in the elementary state. However, it is prone to attack by alkaline metals and Chlorine trifluoride when exposed to high temperatures. This causes phase change crystallization. The crystallinity is also dependent on the sintering temperature.
PTFE has a melting point of 327 degC. As a result, PTFE is used in a wide range of applications, including chemical and metallurgical industry, high frequency communication equipment, textile, and pharmaceutical industry.
During the sintering process, the PTFE is heated in a first vapor oven. Afterward, it is cooled rapidly to room temperature. A second sinter oven is then heated to the same sintering temperature, and then it is cooled to the ambient temperature. Eventually, the PTFE is air cooled to the final size.
After the specimens are rapidly cooled, they have poor particle/matrix bonding and inferior fiber formation. They also show significant dimensional distortion.
In addition, the thermal softening stage of the process results in a minor weight loss of the matrix. After PTFE has been reheated, it reverts back to its original state, but some of the deformations remain as permanent deformations. PTFE has a linear thermal expansion coefficient that varies with temperature. Moreover, the heat content of PTFE increases with temperature.
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