1. PTFE pipe has "cold flow". That is, the plastic deformation (creep) of material products under long-term continuous loading, which brings certain limitations to its application. For example, when a gasket made of PTFE tubing is applied, the bolts are tightened so tightly that when a specific compressive stress is exceeded, the gasket will be flattened due to "cold flow" (creep). These shortcomings can be overcome by adding appropriate fillers and improving the structure of the part.
2. The melt viscosity of PTFE pipe is very high, and it does not flow at high temperatures. It has a melting point above (327 °C), a melt viscosity of 1010Pa.s, and does not flow even if it is heated to the decomposition temperature, which makes it impossible to use the molding method of general thermoplastics, but to use the sintering method similar to powder metallurgy.
3. PTFE pipe has outstanding non-stickiness, which limits its industrial application. It is an excellent anti-stick material, which in turn makes it extremely difficult to bond to the surface of other objects.
4. The thermal conductivity of PTFE pipe is low and the thermal conductivity is relatively high. This not only prevents it from being used as a bearing material, but also makes it impossible to quench thick-walled products.
5. The linear expansion coefficient of PTFE pipe is 10~20 times that of steel, which is larger than that of most plastics, and its linear expansion coefficient changes irregularly with the change of temperature. When applying PTFE, if you don't pay enough attention to this aspect of performance, it is easy to cause losses.
6. When heated above 400 °C, the cracking speed of PTFE tube is gradually accelerated, and the decomposition products are mainly PTFE, perfluoropropylene and octafluorocyclobutane. At temperatures above 475 °C, the decomposition products contain a very small amount of highly toxic perfluoroisobutylene. Note that the heating temperature should not exceed 400°C, and the laboratory should have a good ventilation system to facilitate the elimination of toxic gases.
