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Chemical terminology 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. Safety Controversy developed during the 1990s around allegations that the silicone gel in breast implants was responsible for several health problems, including autoimmune diseases. Systemic reviews were undertaken by governments in a number of countries including Canada (Canadian Expert Advisory Committee review, 1992), Germany, France (ANDEM, 1996), USA (US National Science Panel, 1997-8, UK Independent Review Group 1998, and the U.S. Institute of Medicine, 1999), and the Scientific Technical Opinions Assessment (STOA) report commissioned by the European Parliament in 2001 (updated in 2003). A clear consensus has emerged from these independent scientific reviews that, to date, there is no evidence of a causal link between the implantation of silicones and connective tissue disease. Firestops
Sealants in building construction and maintenance One-part silicone sealants are in common use to seal gaps, joints and crevices in buildings. Silicones are abundantly available for this purpose, in professional, as well as retail grades. One-part silicones cure by absorbing atmospheric moisture, which helps in the professional installation. To make a very smooth silicone seal, apart from masking the edges with tape, if practical, professional caulkers often wet wooden spoons and assorted, hand-crafted wooden tools, which they soak in water with diluted dishsoap. The silicone will not stick to wet, soapy wood, which makes this ideal for creating a perfectly smooth surface. Do-it-yourselfers typically use a moistened finger to trace neat beads into silicone caulking. Similar methods work for urethane caulking, against which silicones compete quite heavily. White silicones can, at times, turn slightly yellow over time. The strength and reliability of silicone rubber is widely acknowledged in the construction industry. Automotive body manufacturing plants and paint shops must avoid the presence of all silicones, as a mere hint of its presence in any form can cause severe failures in automotive paints. Vendors and contractors in such plants are often requested to verify in writing that they will not bring any silicones into the plant. In the plumbing and automotive fields, silicone grease is often used as a lubricant. In plumbing, the grease is typically applied to O-rings in faucets and valves - for example, all official Moen replacement cartridges are pre-lubricated with it. In the automotive field, silicone grease is typically used as a lubricant for brake components since it is stable at high temperatures, is not water-soluble, and is far less likely to foul brake pads. Cooking Applications Silicone is also impregnated into parchment paper and used as a non-stick material for applications such as baking and steaming. The silicone also makes the paper heat- and grease-resistant. This allows the paper to line cookie sheets and act as a replacement for greasing, thereby speeding mass production of baked goods. It is also commonly used in pouch cooking, where ingredients are sealed into a container made of parchment paper and allowed to steam. Silicone rubber is also used to make utensils (notably spatulas) and bakeware. Silicone Producers See also | ||||||||||||
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