or polysiloxane, is an inorganic polymer consisting
of a silicon-oxygen backbone (...-Si-O-Si-O-Si-O-...) with
side groups attached to the silicon atoms. Certain organic
side groups can be used to link two or more of these -Si-O-
backbones together. By varying the -Si-O- chain lengths,
side groups, and crosslinking, silicones can be synthesized
into a wide variety of materials. They can vary in consistency
from liquid to gel to rubber to hard plastic. The most common
type is linear polydimethylsiloxane or PDMS.
The second largest
group of silicone materials is based on silicone resins,
which are formed by branched and cage-like oligosiloxanes.
Silicones are odorless, colorless, water resistant, chemical resistant,
oxidation resistant, stable at high temperature, and have
weak forces of attraction, low surface tension, low freezing
points and do not conduct electricity. They have many uses,
such as lubricants, adhesives, sealants, gaskets, breast
implants, pressure compensating diaphragms for drip irrigation
emitters, dishware, Silly Putty, and many other products.
Due to their thermal stability and relatively high melting
and boiling points, silicones are often used where organic
polymers are not applicable. Their unreactivity generally
makes them non-toxic. Silicone is often mistakenly
referred to as "silicon". Although silicones contain
silicon atoms, they are not made up exclusively of silicon,
and have completely different physical characteristics from
word "silicone" is derived from ketone, and is
technically not the correct term for these polymers.
A true silicone group has a double bond between oxygen and silicon,
like a ketone group with Si in place of C (the same terminology
is used for compounds such as silane, which is an analogue
of methane). Polysiloxanes are called "silicone" due
to an early mistaken assumption about their structure, but it has
since been shown that they contain no silicone groups at all.
can come in many different chemical formulae (due to additives)
giving it different chemical properties,
varying thicknesses -- both of which affect its coefficient
of expansion. Successful long term bonding of silicone
and to other
substrates, requires careful preparation and matching of
being used with the differing
COEs of the substrates involved. BONDiTTM's
A-43 primer is among the few available that can be
used to prime already cured silicone
to bond to substrates with differing COE's for harsh environments.
To see our chart showing elongation rankings of the various
BONDiTTM products click here. Call or email us for advice on
for COE ratings and matching BONDiTTM products for your application
at (707) 284-8808 or firstname.lastname@example.org.