1. The PTFE tube has "cold flow". That is, the plastic deformation (creep) of the material product under long-term continuous load brings certain restrictions to its application. For example, when using gaskets made of polytetrafluoroethylene pipes, tighten the bolts tightly and seal tightly, so that when the specific compressive stress is exceeded, the gasket will produce "cold flow" (creep) and be compressed. broken. These shortcomings can be overcome by adding appropriate fillers and improving the structure of the parts;

2. The melt viscosity of the PTFE tube is very high and does not flow at high temperatures. Above the melting point (327°C), the melt viscosity is 1010 Pa.s. It does not flow even if it is heated to the decomposition temperature, which makes it impossible to use general thermoplastic molding methods, but to use similar powder metallurgy sintering methods to shape;

3. PTFE tube has excellent non-stick performance, which limits its industrial application. Is a good anti-sticking material, this performance makes it difficult to attach to the surface of other objects;

4. PTFE tube has low thermal conductivity and good thermal conductivity. This not only prevents it from being used as a bearing material, but also makes it impossible to harden when manufacturing thick-walled products;

5. The coefficient of linear expansion of PTFE tube is 10-20 times that of steel, which is larger than most plastics. The linear expansion coefficient changes very irregularly with temperature. In the application of PTFE, if insufficient attention is paid to this aspect of performance, it is easy to cause loss;

6. When heated to above 400°C, the cracking rate of the PTFE tube gradually increases, and the decomposition products are mainly tetrafluoroethylene, perfluoropropylene and octafluorocyclobutane. Above 475°C, the decomposition product has a very small amount of highly toxic perfluoroisobutene. Note that the heating temperature should not exceed 400°C, and the laboratory should have a good ventilation system to help eliminate toxic gases.