Silicones
“More precisely called polymerized siloxanes or polysiloxanes, silicones are mixed inorganic-organic polymers with the chemical formula [R2SiO]n, where R is an organic group such as methyl, ethyl, or 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 siloxane is linear polydimethylsiloxane (PDMS), a silicone oil. The second largest group of silicone materials is based on silicone resins, which are formed by branched and cage-like oligosiloxanes.”
(Wikipedia, Silicones, 4/7/2011)
“Silicone polymers are used to serve a wide variety of needs. For example, silicone polymers are used as adhesives, lubricants and sealants. Many factors contribute to shaping the qualities which will both characterize the polymer and ultimately determine its use.”
“The molecular weight of a cured silicone polymer is frequently of significant importance, and silicone polymers possessing molecular weights within a specific range are thus often required. However, a polymer's molecular weight can be difficult to obtain within a desired range.”
“Similarly, the manner in which a silicone polymer is cured plays a large role in determining the particular qualities that will be possessed by the cured polymer. Due to the nature of the methods traditionally used in the synthesis of silicone polymers, curing groups are often located at the terminal ends of the polymer. In such cases, cross-linking will not occur along the length of the polymer, thereby limiting the polymer's strength.”
(Bahram et al, US Patent 7,837,824; 11/23/2010)
Polymers /Resins
Silesquioxanes (POSS)
Silicone Hydrogels
Silicone /Imide Copolymers
Silicone Molds
Silicone Shape Memory Materials
Recent US Patents
11/23/2010
7,837,824
Reactive polyorganosiloxanes having controlled molecular weight and functionality
Bahram et al of Henckel,Connecticut, has developed photoradiation and/or moisture curing silicone compositions. In particular, the methods of the present invention permit controlled growth of a polymer, and allow for incorporation of pendant functional groups along the length of the polymer. (RDC 4/4/2011)