About Silicone and Siloxanes

It has been an established fact, ever since these substances were invented, that “Silicone” did not mean the same thing as “Silicon”.

The word without the ‘e’ at the end, stands for an element in the periodic table, and is therefore a type of atom.

‘Silicone’ always referred to a polymer, which typically contains the elements Silicon, Oxygen, Carbon and Hydrogen, although certain practical preparations of Silicone, may contain additional elements such as Sulfur… This polymer forms chains, in which Silicon atoms alternate with Oxygen (bridging) atoms. Therefore, the Silicone -family of polymers is also referred to as ‘Siloxanes’, which sounds substantially different from ‘Silicon’.

Typical Silicone ‘Cocking Compound’ would be a practical example of the polymer.

I think that the fate which this terminology eventually succumbed to was twofold:

  1. It was always impossible to explain what the difference was supposed to be, to laypeople, and
  2. The spelling of the two words was so similar, that laypeople who saw no reason to distinguish between them in the first place, would also use these two words interchangeably.

It might be, that the modernistic way to refer to the polymer, is just to call it ‘Polysilicon’. (?)

Even though the reader might have hoped for more complexity, there are really only two pathways by which Siloxanes polymerize. They respond to moisture, and either give off Hydrogen Chloride gas, or Acetic Acid, the latter of which also gives Cocking Compound its vinegar-like odor. This would happen in both cases, either because a Chlorine atom, or an Acetate group was attached to the Silicon atoms. With water, the corresponding acid develops, and the Oxygen atom of the water forms the bridge, between two Silicon atoms.

Dirk

 

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