Heat-resistant rubber

A. E. Hirsch and R. J. Boyce, Dynamic Properties of EthjlenefMcrylic Elastomers M New Heat Resistant Rubber Bulletin EA-530.604, Du Pont Polymers, Stow, Ohio, May 1977. 

Like NR, SBR is an unsaturated hydrocarbon polymer. Hence unvulcanised compounds will dissolve in most hydrocarbon solvents and other liquids of similar solubility parameter, whilst vulcanised stocks will swell extensively. Both materials will also undergo many olefinic-type reactions such as oxidation, ozone attack, halogenation, hydrohalogenation and so on, although the activity and detailed reactions differ because of the presence of the adjacent methyl group to the double bond in the natural rubber molecule. Both rubbers may be reinforced by carbon black and neither can be classed as heat-resisting rubbers. 

Return the mixture to the saucepan. Cook over low heat, stirring and scraping the bottom of the pan with a wooden spoon or a heat-resistant rubber spatula, until the mixture is thick enough to coat the spoon. Immediately remove from the heat and strain through a fine-mesh sieve into a bowl with the heavy cream. Chill thoroughly. 

Some typical elastomers are natural rubber, which is gathered from trees, SBR rubber, which is used a lot in motorcar tires, neoprene, as in wet suits and oil seals, EPDM, a general purpose rubber, butyl, a heat-resistant rubber with the ability to keep the air in car tires, nitrile for oil seals, silicones for heat resistance, fluoro-elastomers for chemical resistance, and last but not least, polyurethanes, which cover a number of the above fields. Table 1.1 shows some of the advantages of castable polyurethanes over conventional rubbers. 

All silicone elastomers have high thermal stability. When heated, they do not release toxic products and are used as main ingredients in the production of rubber compounds and heat-resistant rubbers. 

Uses Resin for wire coating, EPDM peroxide-cured modifier, coatings processing aid crosslinking agenL coagent for rubber modifier for rubber, plastics, mastics, adhesives oil well cables heat-resist, rubber Features Thermosetting... 

Hazardous Decomp. Prods. Heated to decomp., emits very toxic fumes of NOx and SOx Uses Curing and vulcanizing agent for heat-resist. rubber applies., e.g., aircraft tires ... 

Precaution Emits acrid fumes on exposure to flames no explosive hazards expected Uses Heat-resistant rubber Trade Name Synonyms Chemigum HR662 [Goodyear... 

There are so-called organic solvent-resistant rubbers and heat-resistant rubbers. Also, there are rubbers that contain microcrystalline parts or molecular associations even in their solution state. NBR, CR, Z,... 

All commercial separators so far have been made of polyolefins, but they provide only limited heat resistance. Research is now focusing on separators made of different materials which would offer superior heat resistance. These include heat-resistant rubber such as silicone mbber and fluororubber, aromatic polyamide resin, liquid crystalline polyester resin, heat-resistant resin containing polyoxyalkylene, and resin with cross-linked groups. Separators made of such materials are expected to demonstrate not only high temperature stability and safety but also superior ion transportation for better rate capability at high current discharge. 

DuPont first introduced ethylene acrylic elastomer in 1975 as a moderately priced oil- and heat-resistant rubber, which was only surpassed by the fluoroelastomers and fluorosilicones, which are much more costly. AEM is known for imparting a good combination of properties such as good compression set resistance, high vibration damping, and good low-temperature flexibility. 

W.M. Stahl, Fluid resistance of Vamac . DuPont Technical Bulletin EA-510.1 (R2). A.E. Hirsch and R.J. Boyce. Dynamic properties of ethylene/acrylic elastomer A new heat resistant rubber. Proceedings of the International Rubber Conference, Brighton, England, May 1997. DuPont Technical Bulletin C-EA-53C.G04. 

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