From: SFPhysics@aol.com
Date: Fri Feb 23 2001 - 02:14:43 PST
From: SFPhysics@aol.com Message-ID: <2f.1155c570.27c79213@aol.com> Date: Fri, 23 Feb 2001 05:14:43 EST Subject: Silicon & Silicone
> Hello!
> I have a hopefully not too inappropriate question for pinholers: Do breast
> implants have silicon, the element, in them? I remember hearing that they
> are made of Silicone, and when we talk about silicon in Chemistry class,
the
> students always think that's what breast implants are made of. Any ideas
or
> info?
> Thanks,
> Jennifer Paillet
>>
Hello Jennifer:
Silicon is the name of the element by itself. With four electrons in the
outer shell it will combine in ways similar to Carbon and can be made into
polymer chains just like hydrocarbons. If two methyl groups (CH3) are
attached to a Silicon atom linked to two Oxygen atoms, sharing only one
electron of each Oxygen, the next Silicon + methyl groups can link to it and
thus make longer chains. This makes Silicon based oils. These oils are
generally referred to a silicone oil, silicone grease, silicone rubber, etc.,
where the letter "e" on the end is just a way of noting that the substance is
a silicon compound in the form of a polymer. General Electric first added
the "e" to the end for their silicon polymer products as an affectation and
trademark. Silicone oils are a common additive to women's hair spray because
they do not harden and do not discolor with exposure to sunlight; thus, most
women who use hair spray will inhale much more silicone oil in their lifetime
than they will get from their implants (assuming a woman who feels the need
to use both).
Breast implants are filled with silicone gel. The outer plastic covering is
a different type of plastic, usually a polycarbonate. Silicone gels were
chosen because of the assumed low toxicity, constant viscosity over a wide
temperature range, and a basic inert nature in case of rupture of the
containment membrane. The real dangers come mostly from the plasticizer
compounds in the containment membrane so the newer prosthesis filled with
salt solution (saline) have little advantage in terms of possible toxicity.
One last note, the child's toy (and grown up Physics instructor's toy) known
as Silly Putty is a silicone rubber.
Al Sefl
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