A Complete Guide to High-Temperature Elastomers (Silicone, Viton, FKM)

The manufacturing relies on special elastomers for critical sealing applications. These materials maintain flexibility and are exposed to intense thermal stress. The most common types include silicone, Viton, and FKM compounds. The aerospace industry depends on these materials for engine compartments. Many automotive manufacturers use them for gaskets, O-rings, and seals.

The high-temp rubber formulations solve problems. The applications continue to develop as technology advances into extreme environments. The research focuses on extending temperature ranges and chemical compatibility further. The manufacturers constantly improve formulations to meet evolving industry needs.

What Are High-Temperature Elastomers?

High-temperature elastomers are special polymeric materials which are able to sustain flexibility even in high-temperature circumstances. These substances are not similar to ordinary rubber substances, which are used in daily life. Their elasticity and ability to withstand heat breakdown are possible due to their molecular structure. 

The majority of the traditional rubbers melt at temperatures above 100 °C. These heat-resistant elastomers can survive long-term temperatures between 150 °C and 350 °C and above.

The unique chemical composition provides exceptional resistance to aging and oxidation processes. Their resistance extends beyond heat to include various chemicals and fluids.

The high-temp rubber can retain its mechanical characteristics during thermal stress, which cannot be said of the conventional alternatives. The applications also include engine seals up to industrial gaskets and O-rings. These materials have processes that need special equipment and skills.

• With -55 °C down to 350 °C, flexible depending on type
• Resists are not broken by exposure to aggressive substances
• Much longer high-temperature service life
• Low-level permanent compression during thermal stress
• Applied in most industries in sealed systems

Silicone Elastomers

Silicone elastomers provide temperature functionality from -55°C to 300°C. The material remains flexible even at extremely low temperatures unlike many alternatives. Most silicone compounds show exceptional resistance to ultraviolet radiation and ozone. The weather exposure causes minimal degradation even after years of outdoor use.

Many electrical components use silicone for its reliable performance and safety. The medical industries use silicone for its biocompatibility and sterilisation tolerance. The material allows oxygen permeability which creates advantages in certain applications. Many companies produce medical-grade versions for the healthcare and pharmaceutical sectors.

One limitation involves poor resistance to petroleum-based oils and fuels. Any applications involving gasoline or lubricants typically require alternative elastomer choices. The tensile strength falls below that of many competing high-temperature materials.

• Available in transparent and various pigmented formulations
• Can be molded, extruded, or applied as a liquid coating
• Exhibits excellent return to the original shape after deformation
• Generally considered tasteless and odourless for sensitive uses
• Self-extinguishing properties in many formulations

Viton/FKM Elastomers

Viton is DuPont's trade name for fluorocarbon elastomers commonly known as FKM. These materials operate effectively in temperature ranges from -26°C to 230°C. The fluorine content provides exceptional resistance to hydrocarbon fuels and oils. Many automotive and aerospace applications depend on these reliable materials. The chemical structure creates barriers against most acids and aliphatic compounds.

The five distinct grades exist: A, B, F, GF, and ETP for different applications. The grade offers specific performance characteristics for targeted industrial needs. The gas permeability rates remain significantly lower than silicone alternatives. Most applications use black formulations due to carbon black reinforcement benefits.

The materials typically cost several times more than standard industrial rubbers. The limitations include poor performance when exposed to ketones and esters. The heat-resistant elastomers like FKM demonstrate superior compression set resistance over time. The material maintains its sealing force even after prolonged compression periods. The viton rubber properties are the best for mechanical durability.

• Need special adhesives to be attached optimally to substrates.
• Increased fluorine level is usually considered to be an indication of increased chemical resistance
• Comes in 50 to 90 Shore A as per any application need
• Improved peroxide systems are used in advanced formulations