Fluorocarbon rubber compounds

High resistance to almost all inorganic chemicals, ammonia being the most important exception. Resistance to most organic compounds, except low molecular weight polar organics. Least resistant of the fluorocarbon rubbers to methanol and phosphate ester based hydraulic fluids. 

Compounding. Compared with the large number of ingredients required in a conventional rubber recipe, fluorocarbon elastomer compounding seems simple (Table 4) (see Rubber Compounding). 

The interesting conclusion was that although conventional automotive -type fluoroelastomer compounds were certainly poorer than nitrile, the high-modulus FKM AHV compound performed best of all. Hence, providing proper selection is made, fluorocarbon rubbers can be considered to be at least as good as nitrile in extrusion resistance. 

An article has been published by Shell [6] that discusses the fundamentals of grinding rubber at low temperatures. It covers a wide range of subjects including the nature of the product produced, its required storage conditions, the economics of the process and the management and quality systems that need to be installed. The article also includes data on the particle size distributions of hydrogenated nitrile rubber (HNBR) crumb and the properties of fluorocarbon rubber (FKM) and HNBR compounds containing different amounts of rubber crumb. 

As has been shown in Chapter 6, in addition to crumb from waste tyres, it is possible to commercially source crumb from a number of other rubber types, e.g., fluorocarbon rubber. Shell [30] has carried out a study whereby micropowder from vulcanised fluorocarbon, silicone and nitrile wire insulation rubber has been put back into wire compounds using an open mill. The loadings chosen were those that maximised the performance and economic efficiency of the formulations. 

The chloride is used to manufacture silicones, tetramethyl lead and triptane (2,2,3 trimethylbutane). Lesser uses include the manufacture of butyl rubber, higher halogenated methanes, methyl cellulose, quaternary ammonium compounds, methyl mercaptan, methionine, fungicides and pesticides (primarily the Me-arsenate herbicides). Recently the chlorinated fluorocarbons have replaced CH3CI as high volume refrigerants and propellants (ref. 32) Tables 12 and 13 list the chemical and physical properties and potential numbers of workers exposed to the monohalomethanes. 

Compounds from solid fluorocarbon elastomers are mixed on the equipment common in the rubber industry. However, the mixing procedures typical for standard types of elastomers are often modified to be suitable for mixing fluorocarbon elastomers. 

The use of aromatic compounds in automotive fuels, higher under-the-hood temperatures, combined with automotive regulations, presents a challenge for the rubber parts (e.g., hose, seals, diaphragms) used in vehicles. Traditional elastomers do not have high enough resistance to meet all these requirements, but fluorocarbon... 

Trichloroethylene and 1,1,1-trichloroethane are used in correction fluids, dry-cleaning products, degreasing sprays, and solvents and spot removers. Bromochlorodifluoro-methane is a compound found in halon fire extinguishers that is abused. Freon is used for refrigeration and air conditioning systems. Anesthetics include halothane, chloroform, and the local anesthetic ethyl chloride. Methylene chloride is a component of rubber cement, paint strippers, and degreasing agents, and fluorocarbons are present in many types of aerosol sprays. 

Many common industrial solvents used in paint, glue, rubber, cement, shoe polish, degreasers, and several gasoline components, as well as a number of fluorocarbons (used as aerosol propellants) and alkyl nitrites, are known to produce a euphoric exhilarating or stimulant effect. Such compounds include volatile aliphatic and aromatic hydrocarbons, halogenated hydrocarbons, ethers, aldehydes, and ketones. 

For many years vessels have been successfully lined with various rubber formulations, both natural and synthetic. Many such vessels have given over 20 years of reliable service. These compounds are still in use today but with the development of newer thermoplastic and elastomeric materials the range of application has been expanded. The newer materials, particularly the fluorocarbons, have greatly increased the ability of linings to protect substrate from corrosive chemicals. However, in order for these lining materials to provide the maximum protection, it is important that the vessel shell be properly designed and prepared and the lining properly installed. Unless these precautions are taken, premature failure is likely to occur. 

Organic compounds and partial oxidation compounds (rubber and plastics, organic solvents, chlorinated hydrocarbons and fluorocarbons, volatile organic compounds, CH, etc.) Organometallic compounds Halogens and their compounds (As, AsH, etc.)... 

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