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Silicone fluids are known to have high Viscosity Indices (VI), and high Oxidation Onset Temperatures (OOT). Silicone VI and OOT characteristics make these fluids appealing for use as lubricants in high temperature applications, and where lubricant longevity is desired. Despite thermal and oxidative benefits, silicones lubricants have a reputation as being poor lubricants in metal-to-metal applications, and are typically only selected for use in plastic applications. Most industrial knowledge about silicone lubricants is based on characteristics of PolyDiMethyl Siloxanes (PDMS), in which case, lubricity limitations do exists. However, there are other silicone based lubricating fluid technologies, that have been commercially available for decades, that far exceed known lubricity performance of PDMS, and in some ways can rival traditional synthetic hydrocarbon.

When designing and employing lubricants, film thickness modeling techniques must be used as part of an overall design approach to insure mating components, in relative motion have proper lubricating films to separate surface asperities. Improper asperity separation will lead to increased friction and wear, and overall reduce system reliability, serviceability, and efficiency. Many of the tools to model tribofilms used today are rooted in empirical studies completed with hydrocarbon based fluids as the lubricating medium. Generally, these modeling techniques have also been applied to non-hydrocarbon based lubricants, and this may not be an accurate method to model such fluids. As demands for improved lubricant performance continue to rise, so too does the need for improved tribofilms modeling techniques. This paper will discuss a modeling techniques developed, in which, silicone based polymer molecular structures are designed with tribological film performance in mind.

Consumers in Europe are purchasing automobiles with diesel engines at an accelerating rate. In addition, European governments are increasingly looking to diesel blends (such as biodiesel, which combines diesel at various levels with oil derived from the Rapeseed plant) as a directly substitutable fuel to 100% petroleum-based diesel. One major concern of the automotive industry is the performance of different elastomeric parts in the new fuels. O-rings made from high modulus fluorosilicone elastomers are used predominantly in automotive fuel line quick-connects. This study reviews the performance of fluorosilicone rubber in diesel and biodiesel blends.

Derived from aerospace technology, silicone film adhesives are elastomeric materials that use a unique filler to obtain superior mechanical and optical properties. The small particle size of the filler reinforces the silicone polymer matrix and also results in an optically transparent adhesive. These film adhesives offer favorable material properties as well as strong adhesion to many substrates. Both the material and adhesion properties are consistent over a broad range of temperatures and humidity. Consistent material properties arise partly because silicone film adhesives have glass-transition temperatures that are well below the typical operating-temperature range for automotive applications (-40°C to 150°C). The low glass-transition temperature ensures that silicone film adhesives remain in the rubbery state.

This paper discusses the selection of a material to be used as a conformal coating on General Motors' Computer Command Control. Included is background information on conformal coating materials, processing, environmental protection properties, and repairability of the cured material. The resulting cost of a material is a combination of all of the above factors.

This paper describes a unique method of fabricating high performance silicone parts with liquid silicone rubber (LSR). Both molding and extrusion techniques will be introduced but emphasis will be on fabrication of automotive ignition core. Liquid silicone rubber offers several advances over current systems. It contains no solvent, is pumpable, and produces a core that is round and smooth, reducing the possibilities of stress point failure in cable construction. Good shelf life and a long working time are characteristic of the system along with rapid cure rates and excellent heat resistance. Data will be presented covering thermal life, electrical conductivity and typical physical properties.

Extensive toxicological studies of polydimethylsiloxanes, popularly referred to as “silicones,” have shown that these materials rank among the least hazardous of all industrial materials. Nonetheless, adoption of silicone brake fluids by only a portion of the automobile industry could result in appreciable environmental imposition, thus posing a potential ecological problem. Considerations such as toxicology, biodegradability, disposal or reuse, and effects on manufacturing personnel and processes are as important as the more visible performance parameters, and must be resolved satisfactorily. These topics are the subject of this paper.

The high-temperature properties of silicone rubber are compared to those of six organic rubbers. New data on properties at temperature, as distinct from standard heat aging data, are presented to guide the designer and materials engineer. The properties of fluorosilicone rubber are also discussed. Current automotive applications of both silicone rubber and fluorosilicone rubber are described.