PTFE has a high melting point, high melt viscosity, and is sensitive to shear in the amorphous state, and is prone to melt fracture. Therefore, conventional thermoplastic molding methods such as melt extrusion and injection molding cannot be used, and only similar powders can be used. Metallurgical methods are used for sintering. To
PTFE filling can be pre-formed by plunger, freely sintered or extruded. The above method is usually suitable for products with a certain wall thickness, and is not suitable for processing PTFE films. (Ptfe film) In recent years, China has carried out a lot of research. More mature processing technologies include calendering for dispersible PTFE resin, metal turning of PTFE sintered products with low hardness and good toughness, as well as conventional extrusion methods and in the extrusion processing of calcining methods, the resin is directly processed by raw materials. No need to melt and plasticize. In addition to the above-mentioned one-time processing technologies, there are some newly developed secondary processing technologies that are worthy of attention, such as PTFE vacuum forming technology, hot pressing and hot blow molding technology, and isostatic pressing processing technology. Teflon is the preferred material for corrosion-resistant lining, suitable for corrosion-resistant pipes, fittings, bellows, pumps, valves, kettles, storage tanks, towers and various standard equipment; as machinery, petrochemical, transportation, textile and construction industries The sealing materials are widely used; Teflon can also be used as valves, bearings, piston rings, guide rails, etc. Corrosion-resistant and low-friction parts; According to the PTFE membrane treatment, it has selective air permeability and can be used as a separation material to selectively pass gas or liquid, especially to filter corrosive liquids; Because PTFE has excellent biocompatibility In recent years, many people have conducted in-depth research as biological materials.
In recent years, PTFE membranes as artificial blood vessels and other artificial organs have been developed at home and abroad. Heart valves and the like have been used clinically as prosthetic blood vessels and prosthetic stent materials for rhinoplasty, and have achieved good results. According to the current research, production and application status at home and abroad, China should vigorously develop modified polytetrafluoroethylene materials to make them commercialized, serialized, and high-performance. It is particularly important to prioritize the development of high demand for glass fiber, carbon fiber, graphite and copper. Powder-filled PTFE, making full use of China’s rare earth resources, the development of new varieties of rare-earth-filled PTFE and nano-modified PTFE will become a key research direction in China.
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