silicone article

[wannafbody]

so it would seem as if silicone resins are different than PDMS.



I reposted the whole article below.

[wannafbody]

From Wikipedia, the free encyclopedia

Jump to: navigation, search

Not to be confused with Silicon.



Silicones, or polysiloxanes, are inorganic-organic polymers with the chemical formula [R2SiO]n, where R = organic groups such as methyl, ethyl, and phenyl. These materials consist of an inorganic silicon-oxygen backbone (...-Si-O-Si-O-Si-O-...) with organic side groups attached to the silicon atoms, which are four-coordinate. In some cases 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 with a wide variety of properties and compositions. 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.





Chemical structure of polydimethylsiloxane (PDMS).

Self-leveling silicone firestop system used around copper pipe through-penetrations in a two-hour fire-resistance rated concrete floor assembly.Contents [hide]

1 Chemical terminology

2 Safety

3 Firestops

4 Sealants in building construction and maintenance

5 Cooking Applications

6 Silicone Producers

7 See also

8 External links







[edit] Chemical terminology



A hypothetical silicone group. Such species do not exist, see text.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 elemental silicon.



The word "silicone" is derived from ketone. Dimethylsilicone and dimethyl ketone (a.k.a. acetone) have analogous formulas, thus it was surmised incorrectly that they have analogous structures. The same terminology is used for compounds such as silane, which is an analogue of methane). A true silicone group with a double bond between oxygen and silicon do not exist (see figure), Polysiloxanes are called "silicone" due to early mistaken assumptions about structure.







I think I got the whole article.

[DM101]

So what does this refer to? I missed the first part I guess.