Articles with Abstracts
Articles without Abstracts
Patents with Abstracts
Patents without Abstracts
Polyhedral Oligomeric Silsesquioxane (POSS)
Silicone Contact Lenses
Silicones: Environmental Effects
“Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications (e.g., breast implants), cookware, and insulation.
Silicones are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements. Some common forms include silicone oil, silicone grease, silicone rubber, and silicone resin.
of the most useful properties of silicones include:
Low thermal conductivity
Low chemical reactivity
Thermal stability (constancy of properties over a wide temperature range of −100 to 250 °C).
The ability to repel water and form watertight seals, although silicones are not hydrophobes.
Does not stick to many substrates, but adheres very well to others, e.g. glass.
Does not support microbiological growth.
Silicones have excellent resistance to oxygen, ozone, and ultraviolet (UV) light. This property has led to widespread use of silicones in the construction industry (e.g. coatings, fire protection, glazing seals) and the automotive industry (external gaskets, external trim).
Good electrical insulation. Because silicone can be formulated to be electrically insulative or conductive, it is suitable for a wide range of electrical applications.
They have high gas permeability: at room temperature (25 °C), the permeability of silicone rubber for such gases as oxygen is approximately 400 times that of butyl rubber, making silicone useful for medical applications in which increased aeration is desired. However, silicone rubbers cannot be used where gas-tight seals are necessary.
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, 5/2/2012)
In this day of overworked technical people, keeping up is nearly impossible. Maro's mission is to help keep up in as little time as possible. Bookmark this page and check it often. You will be surprised what can be picked up in just a few moments spent each day.
These pages list the links as they are found. Some will abstracted and added to Maro Topics. (RDC 2/7/2012)
Roger D. Corneliussen
Maro Polymer Links
Tel: 610 363 9920
Fax: 610 363 9921
Copyright 2012 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen
* Date of latest addition; date of first entry is 5/2/2012.