Polycarbon fluorides

Graphite reacts with alkali metals, for example potassium, to form compounds which are non-stoichiometric but which all have limiting compositions (for example K C) in these, the alkaU metal atoms are intercalated between the layers of carbon atoms. In the preparation of fluorine by electrolysis of a molten fluoride with graphite electrodes the solid compound (CF) polycarbon fluoride is formed, with fluorine on each carbon atom, causing puckering of the rings. 

Four main groups of compounds may be distinguished polycarbon fluorides, oxosalts, oxides and sulphides. 

The (CF ), cathode is stable in contact with organic electrolyte systems, and the cells have a satisfactory shelf life. In common with other lithium power sources, polycarbon fluoride-based cells may suffer from voltage delay, but only under severe discharge conditions. 

Four main groups of systems may be distinguished polycarbon fluorides, sulfides, oxo-salts, and oxides. Oxosalt batteries are in a range of commercial power sources based on silver chromate, Ag2Cr04, with the discharge process... 

Polycarbon fluorides of the general formula CV n can be obtained by direct fluorination of carbon black or other varieties of carbon at high temperatures. Theoretical specific energy density 2600 Wh kg can be achieved with these materials. Lithium cells with polycarbon fluoride cathodes have an open-circuit voltage in the range of 2.8-3.3 V, depending on the composition of the cathode material. A typical cell reaction may be written [64] ... 

Cells based on polycarbon fluorides are manufactured commercially in various forms. System developed by Matsushita Electric Industrial Co. is designed as a BR 435 cylindrical cell. Cells constmcted by Nippon Steel Co. use carbon fibers as electrodes they are found to be rechargeable. Cells for military applications have... 

In 1954 the surface fluorination of polyethylene sheets by using a soHd CO2 cooled heat sink was patented (44). Later patents covered the fluorination of PVC (45) and polyethylene bottles (46). Studies of surface fluorination of polymer films have been reported (47). The fluorination of polyethylene powder was described (48) as a fiery intense reaction, which was finally controlled by dilution with an inert gas at reduced pressures. Direct fluorination of polymers was achieved in 1970 (8,49). More recently, surface fluorinations of poly(vinyl fluoride), polycarbonates, polystyrene, and poly(methyl methacrylate), and the surface fluorination of containers have been described (50,51). Partially fluorinated poly(ethylene terephthalate) and polyamides such as nylon have excellent soil release properties as well as high wettabiUty (52,53). The most advanced direct fluorination technology in the area of single-compound synthesis and synthesis of high performance fluids is currently practiced by 3M Co. of St. Paul, Minnesota, and by Exfluor Research Corp. of Austin, Texas. 

Materials. Beside inorganic materials (eg, barium chloride/fluoride crystals, doped with 0.05% samarium), transparent thermoplasts are preferred for the PHB technique, eg, poly (methyl methacrylate) (PMAIA), polycarbonate, and polybutyral doped with small amounts of suitable organic dyes, organic pigments like phthalocyanines, 9-arninoacridine, 1,4-dihydroxyanthraquinone [81-64-1] (quinizarin) (1), and 2,3-dihydroporphyrin (chlorin) (2). 

Flame resistance The underwriters ruling on the use of self-extinguishing plastics for contact-carrying members and many other components introduces critical material selection problems. All TSs are basically self-extinguishing. Nylon, polyphenylene oxide, polysulfone, polycarbonate, vinyl, chlorinated polyether, chlorotrifluoroethy-lene, vinylidene fluoride, and fluorocarbon are examples of TPs that may be suitable for applications requiring self-extinguishing properties. Cellulose acetate and ABS are also available with these properties. Glass reinforcement improves these materials considerably. 

Eye exposure, to hydrogen fluoride, 14 18 Eye irritation, in spas/hot tubs, 26 197-198 Eyehners, 7 862 Eye makeup, 7 861-862 Eye shadows, 7 862 Eyewash fountains, 21 849 Eyewear, polycarbonate, 19 809 Eyring equation, 13 407 Eyring transfer matrix technique, 1 32 Ezetimibe (zetia), 5 143—144... 

Carbon fluoride [also known as carbon monofluoride, polycarbon monofluoride, graphite fluoride, or (CFx)n] is a solid, layered, non-stoichiometric fluorocarbon of empirical formula CFX, where 0 < x < 1.25, obtained by the action of elemental fluorine on carbon. Fluorine combines with carbon and yields three solid compounds CFX, C2FX, and C4FX as well as varying amounts of volatile fluorocarbons as byproducts. With appropriate selection of fluorination conditions nearly 100% conversion of carbon to carbon tetrafluoride can occur. 

An ideal kinetic study would be made under conditions where the product is only graphite fluoride or polycarbon monofluoride with no byproducts formed. In terms of reaction kinetics, one method to follow the reaction is to measure the weight change as a function of the reaction time. Using this method the reaction rate of fluorine with carbon can be evaluated. Various carbon structures have been employed with sufficient fluorination contact time provided at a particular temperature for the carbon to reach fluorine saturation. The weight increase vs the temperature can be monitored at atmospheric pressure. Figure 515 shows the carbon structure and the temperature dependency of the fluorination reaction of various graphites. 

Focusing collectors are usually cast acrylic Fresnel lenses, or mirrors of aluminized polyester film in frames of aluminum. These reflectors are either enclosed in a bubble of poly(vinyl fluoride) film, or under polycarbonate glazing, which may be covered with a fluorocarbon film to reduce the reflectivity. The absorbers for active systems are copper or aluminum since the temperatures are too high (325—370°C) for plastics. The frames, however, can be molded ABS, high density polyethylene or polyurethane, either solid or structural foam. Polybutylene or chlorinated PVC can be used for piping hot water, and tanks can be made of either reinforced polyester or blow- or rotational-molded, high density polyethylene (12—15). 

Kawai (1) and (2) (1969) found that polar polymer films such as PVDF, poly (vinyl fluoride), PVC, nylon 11, and polycarbonate exhibit a strong piezoelectricity when they are drawn and then polarized under a high cLc. field Ep at a high temperature Tp and cooled keeping the d.c. field. The piezoelectricity thus obtained depends on Ep, Tp, and poling period. An improved poling technique was reported by Edelman, Grisham, Roth, and Cohen (1970). 

More recently there has been interest in Japan in the surface fluorination of poly(vinyl fluoride) (2) and the surface fluorination of polycarbonates, polystyrene, and poly(methyl methacrylate) (21). 

The principles behind ultrafiltration are sometimes misunderstood. The nomenclature implies that separations are the result of physical trapping of the particles and molecules by the filter. With polycarbonate and fiberglass filters, separations are made primarily on the basis of physical size. Other filters (cellulose nitrate, polyvinylidene fluoride, and to a lesser extent cellulose acetate) trap particles that cannot pass through the pores, but also retain macromolecules by adsorption. In particular, these materials have protein and nucleic acid binding properties. Each type of membrane displays a different affinity for various molecules. For protein, the relative binding affinity is polyvinylidene fluoride > cellulose nitrate > cellulose acetate. We can expect to see many applications of the affinity membranes in the future as the various membrane surface chemistries are altered and made more specific. Some applications are described in the following pages. 

Flame retardants - [TEXTILES-FINISHING] (Vol 23) - [ALUMENUMCOMPOUNDS - INTRODUCTION] (Vol2) -antimony as [ANTIMONY AND ANTIMONY ALLOYS] (Vol 3) -antimony compds as [ANTIMONY COMPOUNDS] (Vol 3) -antimony compds as [ANTIMONY COMPOUNDS] (Vol 3) -based on ammonium sulfamate [SULFAMIC ACID AND SULFAMATES] (Vol 23) -bromine in [BROMINE] (Vol 4) -in electronic applications [PACKAGING - ELECTRONIC MATERIALS] (Vol 17) -iron fluoride in mfg of [FLUORINE COMPOUNDS, INORGANIC - IRON] (Vol 11) -nickel compounds as [NICKEL COMPOUNDS] (Vol 17) -phosphorus for [PHOSPHORUS] (Vol 18) -polycarbonates in [POLYCARBONATES] (Vol 19) -from propylene oxide [PROPYLENE OXIDE] (Vol 20) -for rubbers [RUBBERCHEMICALS] (Vol 21) -use m electrical connectors [ELECTRICAL CONNECTORS] (Vol 9)... 

PC PE PES PET PF PFA PI PMMA PP PPO PS PSO PTFE PTMT PU PVA PVAC PVC PVDC PVDF PVF TFE SAN SI TP TPX UF UHMWPE UPVC Polycarbonate Polyethylene Polyether sulfone Polyethylene terephthalate Phenol-formaldehyde Polyfluoro alkoxy Polyimide Polymethyl methacrylate Polypropylene Polyphenylene oxide Polystyrene Polysulfone Polytetrafluoroethylene Polytetramethylene terephthalate (thermoplastic polyester) Polyurethane Polyvinyl alcohol Polyvinyl acetate Polyvinyl chloride Polyvinyl idene chloride Polyvinylidene fluoride Polyvinyl fluoride Polytelrafluoroethylene Styrene-acrylonitrile Silicone Thermoplastic Elastomers Polymethylpentene Urea formaldehyde Ultrahigh-molecular-weight polyethylene Unplasticized polyvinyl chloride... 

Polycarbon monofluoride is also known as carbon fluoride or graphite fluoride. This material is of strategic importance for the industrialized nations. It plays a very important role due to its unique properties which have been responsible for its large industrial demand. The chemists have not settled their scores to confirm whether it is inorganic or organic compound but one thing is sure that the industry is exploring this compound continuously. 

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