Polytetrafluoroethylene (PFA) VS. Polytetrafluoroethylene (PTFE)

1. Chemical structure difference:

PFA incorporates perfluoroalkoxy, which is equivalent to one of the fluorine atoms in PTFE being replaced by a perfluoroalkoxy. A carbon is directly attached to an oxygen, and then the oxygen is attached to a group such as perfluoromethyl or perfluoroethyl. Compared with PTFE, it reduces the melt viscosity and facilitates processing. The rest of the properties with PTFE is not too much difference.

2. The difference in application:

PFA has the same excellent properties as PTFE, but also has good thermoplasticity, and can be thermoplastic processed with the processing methods of ordinary thermoplastic resins. It is produced by copolymerizing PTFE and perfluoropropyl vinyl ether in a certain proportion in aqueous medium containing perfluorocarboxylate dispersant and persulfate initiator, and is viewed as white translucent particles. It not only has the same service temperature as PTFE, but also has better mechanical strength at 250℃ (about 2~3 times) and excellent stress crack resistance. It has wide processing range and good molding performance, suitable for compression molding, extrusion, injection molding, transfer molding and other molding processes. It can be used to make wire and cable insulating sheaths, high-frequency and ultra-high-frequency insulating parts, corrosion-resistant linings for chemical pipelines, valves and pumps; special spare parts for the machinery industry, various anticorrosive materials for the light textile industry, and Polytetrafluoroethylene anticorrosive linings, and other welding rods. It is made by extruding fusible PTFE granules, with the appearance of semi-transparent milky white, smooth surface, dense and uniform cross-section. It is specially used in the welding of PTFE plate and pipe, so that PTFE products with simple shape can be welded into products with complex shape and large size. Water dispersion is obtained by adding emulsifier to the copolymer obtained by copolymerization reaction of PTFE and perfluoropropyl vinyl ether, and then concentrated at a certain temperature. The solid content is 30%±1%. Appearance is milky white or light yellow translucent. It has various excellent properties of fusible PTFE resin. It can be used for a long time at 260℃, and with its excellent anti-adhesive, anti-corrosion, easy processing performance developed into advanced coatings, spraying, impregnation, and is used in a large number of photocopying technology and food industry as anti-adhesive, anti-corrosion materials.

PTFE--Polytetrafluoroethylene is produced by polymerization of tetrafluoroethylene monomer by suspension or dispersion method. Molecular weight = 5.2×105-4.5×107, white powder, 75% of 400 purposes, odorless, tasteless, non-toxic. Relative density 2.1-2.3, refractive index 1.37, glass transition temperature 327℃, thermal decomposition temperature 415℃. In 400 ℃ above a trace of weight loss and decomposition of toxic gases. Use temperature -250 ~ 260 ℃, in 210 ℃ use up to 10,000 h. Excellent chemical resistance, resistant to any strong acid (including aqua regia), strong alkali, grease, insoluble in any solvent, very low coefficient of friction, good abrasion resistance and self-lubricating. Excellent aging resistance. Excellent electrical properties, good arc resistance. Non-sticky, almost all the sticky substances can not adhere to its surface, completely non-combustible. It has the name of "Plastic King". Tensile strength (MPa) > 23 Elongation (%) > 250.

3. Processing differences:

The main difference in processing is that PFA can be hot melt injection molding, while PTFE can not be hot melt injection molding.

The above is an introduction to the difference between PFA and PTFE materials.

For a long time, PTFE has been sought after by industry because of its superior physical and chemical properties. However, the limitations of its processing methods have caused many scientists and engineers to suffer a lot. Finally, after the introduction of PFA to the market, received the plastics industry new sought-after. This material, with properties similar to those of PTFE, has excellent processing properties, thus solving the engineers' problems.