High-Performance
Silicone
Rapidly changing technology and expectations of increasing
reliability are creating a demand for higher-performance materials
in many applications. This trend is especially true in high-technology
applications. Extremely high-performance demands are being made
of traditional rubbers or, more broadly, elastomers.
The
main performance properties that define an elastomer are low
modulus, high flexibility and low compression set. By their
nature, elastomers are ideal for sealing gaskets, and as flexible
electrical insulation, vibration dampeners, and bonding films.
These elastomers now have to perform to higher environmental
standards then ever before. Electronic components are proliferating
on every industry platform and these components are becoming
denser and more complex, therefore requiring more sophisticated
thermal management systems then ever before. High-performance
silicone-based polymers often offer the most cost-effective
solution. |
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Silicone advantages
Silicone
and organic rubbers are both excellent examples of elastomers. Organic
rubbers are long-chain molecules based on a polymer chain of carbon
atoms. Silicone polymers are based on a polymer of silicone atoms.
Both organic and silicone elastomers often have complex side-chain
substitutions to enhance specific properties, but it is the elastomer's
polymeric backbone that dominates in performance. Silicone has quartz
as a precursor material and organic rubber has petroleum. Silicone
elastomers exhibit the widest operating temperature range of any
elastomer. Silicones will easily retain their elastomeric properties
from -120oF to +450oF. Organics, on the other
hand, have and elastomeric operating temperature range from about
-30oF to +300oF. The nature of the silicone
backbone results in superior temperature resistance at all ranges.
In previous
years silicone has not been a design engineer's first choice in
elastomers due to cost and budgetary restraints. However, because
of increasing performance requirements and emphasis on reliability,
silicone-based products have emerged as the only choice in many
cases. As silicone-based materials have become a more standard solution,
their cost has declined to a point where silicones are generally
equal in initial cost to high-end organics at the unit component
level.
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Silicone materials
can now be designed for special environments including fuel
resistance, thermal conductivity, electrical insulation or even
for electrical conduction. Silicones can be supplied as calendered
sheets, extruded profiles, gels, liquids, high-consistency rubbers
and can be fabricated into combinations of all of these forms.
Of
particular interest is a newly evolving application for silicone
as a bonding adhesive. Specific applications such as heatsink
bonding require the permanent mating of two materials with highly
dissimilar coefficients of thermal expansion. The bonding interface
of this composite will experience a high degree of shear force
due to the relative movement of the planar surfaces. The natural
elastomeric properties of silicone will allow independent planar
movement, thus 'decoupling' the shear forces and eliminating
bond failure areas. |
Safety considerations
In the
areas of health and safety, silicone materials are being used more
frequently because silicone has favorable properties in the areas
of fire propagation, ignition factors and smoke and toxicity during
a continuous burn. Silicones are inherently self-extinguishing and
can be made to meet virtually any flame requirement with innocuous
additives. Silicone generates very little smoke and virtually no
harmful chemical byproducts during combustion. These characteristics
make silicone the idea material for fiberglass-coated fabrics for
use as flame barriers and separator panels.
So,
materials and design engineers can now incorporate silicone performance
advantages into many solutions with the initial economic equivalence
to organics but with the long-term reliability economics only silicone
can offer.
Arlon is the industry leader and offers extensive experience
and expertise in custom compounding, calendering, and application
engineering. Go to our capabilities section and find
out how Arlon can custom design materials and processes to meet your
demanding and complex requirements.
Challenge Us!
Let Arlon be your company's silicone development department.
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