Teflon thermal stability

Teflon PEA 440 HP is a chemically modified form of PEA 340 that provides additional benefits such as enhanced purity and improved thermal stability. This product is suitable for producing tubing, pipe linings for production of ultrapure chemicals, semiconductor components, and fluid handling systems for high performance filters (31). 

However, several articles in the area of microwave-assisted parallel synthesis have described irradiation of 96-well filter-bottom polypropylene plates in conventional household microwave ovens for high-throughput synthesis [16-19]. While some authors have not reported any difficulties associated with the use of such equipment [19], others have experienced problems in connection with the thermal instability of the polypropylene material itself [17] and with respect to the creation of temperature gradients between individual wells upon microwave heating [17, 18]. While Teflon (or similar materials such as PFA) can eliminate the problem of thermal stability, the issue of bottom-filtration reaction vessels has not yet been adequately addressed. 

N-halamines, 13 100-101 of ion-exchange resins, 14 401-402 of ionic liquids, 26 845-847 of olefin fibers, 11 229 of organic semiconductors, 22 209 of polyimides, 20 277 of silicones, 22 600 of Teflon AF, 18 340 Thermal stability tests, of organic peroxides, 18 491... 

Chlorine trifluoride oxide is stable at ambient temperature and can be stored and handled in well-passivated metal, Teflon, or Kel-F containers without decomposition. Its thermal stability is intermediate between that of CIF3 and CIF5. When heated to 280-300°C in a Monel cylinder (37,226), or to 200°C in a stainless steel cylinder, or to 350°C in a flow system (226), CIF3O decomposes ... 

All polyolefins have low dielectric constants and can be used as insulators, ill particular, PMP has llie lowest dielectric constant among all synthetic resins. As a result, PMP has excellent dielectric properties and a low dielectric loss factor, surpassing those of other polyolefin resins and polytetrafluoroethylene (Teflon) These properties remain nearly constant over a wide temperature range. The dielectric characteristics of polyfvinylcyclohexane) are especially attractive its dielectric loss remains constant between-180 and 160 C, which makes it a prospective high frequency dielectric material of high thermal stability. 

Teflon, a fluorocarbon polymer, is well known for chemical inertness, thermal stability at temperatures up to 290°C, and excellent electrical insulating properties. Most inorganic and many organic compounds are insoluble in it. Teflon also exhibits a relatively large hydrogen gas permeability. It, therefore, has potential as a selective osmotic membrane for hydrogen. 

PPFMs, particularly, Teflon AF and polytetrafluoro ethylene Excellent electrical Properties (Eowest dielectric constant among most polymers < 2) Poor thermal stability Adhesion problems High thermal expansion coefficients... 

Glass and plastic vessels (but not nitrocellulose centrifuge pots) can be dried in an oven at the following temperatures, which depend on the thermal stability of the material polyvinyl chloride 70 °C polystyrene 70 °C polyethylene 80 °C high density polyethylene 120 °C polyallomer 130 °C polypropylene 130 °C polycarbonate 135 °C teflon 180 °C and glass 200 °C. 

Fluorine substitution on carbon confers particular reactivity because of its particular properties Fluorine as the most electronegative element forms very strong CF bonds which are sized to "cover" perfluorocarbons tightly. Polytetrafluoroethylene (Teflon) is one practical example illustrating the exceptional chemical and thermal stability of saturated perfluorocarbons in a sharp contrast to explosive tetrafluoroethylene or to fluoroacetylenes. 

All three commercial amorphous fluoropolymers. Teflon AF, Hyflon AD, and Cytop posses a unique set of properties. All dissolve in fluorinated solvents and thus may be spin coated to produce thin hlms and coatings. The polymers may also be extruded and molded using traditional polymer processing techniques. Note that the polymers are not soluble in hydrocarbon solvents or water and retain the chemical and thermal stability of perfluorinated polymers such as Teflon . These polymers have lower density than the well-known semicrystalline perfluorinated polymers such as pTFE that results in lower refractive index, lower thermal conductivity, higher gas permeability, and lower dielectric constant. The polymers are transparent and have excellent mechanical properties below their Tg due to their amorphous character. The presence of a heterocyclic ring in the polymer backbone of these materials is key... 

Fluorine is used to prepare fluorocarbons— very stable carbon—fluorine compounds used as refrigerants, lubricants, and plastics. Teflon ( FIGURE 22.9) is a polymeric fluorocarbon noted for its high thermal stability and lack of chemical reactivity. 

Teflon AF is an amorphous copolymer of tetrafluoroethylene (TFE) and 2,2-bis(trifluoromethyl)-4,5-difluoro-l,3-dioxole (PDD). It combines the properties of amorphous plastics, such as optical transparency and solubihty in organic solvents, with those of perfluorinated polymers, including high thermal stability, excellent chemical stability, and low surface energy. Moreover Teflon AF exhibits the lowest dielectric constant (1.90 for Teflon AF 2400) and the lowest re-... 

---