Fluorosilicone elastomers properties

Mascia, L., Pak, S.H., and Caporiccio, G. Properties Enhancement of Fluorosilicone Elastomers with Compatibilized Crystalline Vinylidene Fluoride Polymers, Eur. Polym. J. 31(5), 459 65, 1995. 

Electrical properties — dielectric constant (e), representing polarization dissipation factor (tan 8), representing relaxation phenomena dielectric strength (EB), representing breakdown phenomena and resistivity (pv), an inverse of conductivity — are compared with other polymers in Table 5.14.74 The low dielectric loss and high electrical resistivity coupled with low water absorption and retention of these properties in harsh environments are major advantages of fluorosilicone elastomers over other polymeric materials.74... 

In a general article about fluorosilicone elastomers [41], Kim analyzed the properties of classical fluorosilicones - [(R)(RF)SiO] - that are an excellent resistance to solvents, a good thermal and oxidative stability, an outstanding flexibility at low temperature. He concluded that fluorosilicones are superior to fluorocarbon elastomers, but they were not very good at high temperatures (above 450 C). Conventional polydimethylsiloxanes, and classical fluorosilicones, present the drawback to give reversion or depolymerization at high temperature, which deteriorates the physical properties. 

Y. Cui, W. Jiang, D. Li, C. Niu, S. Feng, Preparation and properties of fluorosilicone and fluorosilicone elastomer with various contents of trifluoropropyl groups, e-Polymers 11 (1) (2011)302-314. 

L. Mascia, S.H. Pak, G. Caporiccio, Properties enhancement of fluorosilicone elastomers with compatibilised crystalline vinylidene fluoride polymers, Eur. Pol. J. 31 (5) (1995) 459 65. 

The use of silicone elastomers for high-voltage applications (insulators and cable accessories) requires special formulations. Unusually, stringent requirements for these materials must be met.509,510 Fluorosilicone rubbers, which offer some unique combinations of properties (e.g., chemical resistance and higher temperature stability), have attracted considerable attention and have been reviewed in recent publications.511,512 It was noted that a modification of perfluoroether elastomers with silicone elastomer via hydrosilylation reaction opens the possibility of novel applications.5... 

Property ECO, CO Epichlrohydrin homopolymer and copolymer Fluorosilicone EPDM Ethylene propylene CSM Chlorosulfonated polyethylene FPM Fluorocarbon elastomers... 

Most commercial fluorocarbon elastomers have brittle points between -25°C (-13°F) and -40°C (-40°F). The low-temperature flexibility depends on the chemical structure of the polymer and cannot be improved markedly by compounding. The use of plasticizers may help somewhat, but at a cost of reduced heat stability and worsened aging. Peroxide-curable polymers may be blended with fluorosilicones, but such blends exhibit considerably lower high-temperature stability and solvent resistance and are considerably more expensive than the pure fluorocarbon polymer. Viton GLT is a product with a low brittle point of -51°C (-59°F) [48]. Tecnoflon for containing a stable fluorinated amide plasticizer reportedly exhibits improved low-temperature hardness, brittle point, and compression set without sacrificing physical properties [66]. Low-temperature characteristics of selected fluorocarbon elastomers are listed in Table 5.13 [9]. 

Silicone elastomers are heat, aging, and chemical resistant. They are characterized by having unmodified mechanical properties over a wide temperature range from -70 to 200 ""C. Standard types are available in a hardness of 20 to 90 Shore A. Electrically conductive types, fluorosilicone types, oil-bleeding, fast cross-linking, and hard modified types are offered. 

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. 

Cured fluoroelastomers can withstand prolonged exposure to high temperatures and retain their elastomeric, mechanical, chemical, and electrical properties better than other elastomers. Continuous service at 450 F is common intermittent exposure at 600 F is possible. Although resistance to compression set is excellent at 400-450 F, low temperature properties (including compression set) are poor, compared to silicones and fluorosilicones. 

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