欧美日韩精品一区二区在线视频,欧洲女人性开放免费网站 ,女被啪到深处喷水gif动态图,assbbwbbwbbwbbwbw精品,色偷拍亚洲国产大姐,a篇片在线观看网站,呦泬泬精品导航,欧美高清在线精品一区,免费国产a国产片高清,天天天天做夜夜夜做,久久99久国产麻精品66

The first is the difference in chemical structure:

PFA is added with a perfluoroalkoxy group, which corresponds to a fluorine atom in PTFE being replaced by a perfluoroalkoxy group. A carbon is directly attached to an oxygen, and then the oxygen is connected to a group such as a perfluoromethyl group or a perfluoroethyl group. The reduced melt viscosity is advantageous for processing compared to PTFE. The rest of the properties are not too bad with PTFE.

The second is the difference between the applications:

PFA--has the same excellent properties as polytetrafluoroethylene, and has good thermoplasticity. It can be processed by ordinary thermoplastic resin processing methods. It is prepared by copolymerization of tetrafluoroethylene and perfluoropropyl vinyl ether in a certain ratio in an aqueous medium containing a perfluorocarboxylic acid salt dispersing agent and a persulfate initiator, and is observed as a white translucent particle. It has not only the same use temperature as polytetrafluoroethylene, but also has better mechanical strength (about 2 to 3 times) at 250 ° C, and is excellent in stress crack resistance. It has a wide processing range and good molding performance, and is suitable for molding processing such as compression molding, extrusion molding, injection molding and transfer molding. It can produce wire and cable insulation sheath, high frequency and ultra high frequency insulation parts, corrosion resistant lining of chemical pipelines, valves and pumps; special spare parts for machinery industry, various anticorrosive materials for textile industry, PTFE anticorrosive lining Wait for the electrode. It is made of extrudable polytetrafluoroethylene pellets and has a translucent milky white appearance, a smooth surface and a uniform cross section. It is specially used for the welding of Teflon plates and tubes, and the products with simple shape of Teflon are welded into parts with complicated shapes and large dimensions. The aqueous dispersion is obtained by copolymerizing a copolymer obtained by copolymerization of tetrafluoroethylene and perfluoropropyl vinyl ether, and concentrating at a certain temperature. The solid content is 30% ± 1%. The appearance is milky white or light yellow translucent. It has various excellent properties of a fusible polytetrafluoroethylene resin. It can be used at 260 °C for a long time, and it is developed into advanced coating with its excellent anti-sticking, anti-corrosion and easy processing properties. It can be sprayed and dipped. It is widely used in copying technology and food industry as anti-adhesive and anti-corrosion materials.

PTFE-polytetrafluoroethylene is obtained by polymerizing a tetrafluoroethylene monomer by suspension or dispersion. Molecular weight = 5.2 x 105 - 4.5 x 107. White powder, 400% accounted for 75%, tasteless, beautiful, non-toxic. The relative density is 2.1-2.3, the refractive index is 1.37, the glass transition temperature is 327 ° C, and the thermal decomposition temperature is 415 ° C. At 400 ° C or above, there is a slight loss of weight and decomposition of toxic gases. The use temperature is -250 ~ 260 °C, and can be used up to 10000h at 210 °C. Excellent chemical resistance, resistant to any strong acid (including aqua regia), strong alkali, grease, insoluble in any solvent, very low friction coefficient, good wear resistance, and self-lubricating. Excellent aging resistance. Excellent electrical properties and good arc resistance. It is non-tacky and almost all of the viscous material does not adhere to its surface and is completely non-flammable. Known as the "plastic king." Tensile strength (MPa)>23 Elongation (%)>250.

Again, the difference in processing methods:

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

The above is an introduction to the difference between PFA and PTFE materials. For a long time in the past, PTFE has been sought after by the industry for its superior physical and chemical properties. But the limitations of its processing methods have made many scientists and engineers annoyed. Finally, after the PFA launched the market, it received a new appeal from the plastics industry. This performance is similar to that of PTFE and has excellent processing properties, which solves the engineers' problems.