Patents with Abstracts
Carbon Fiber Composites
“Carbon fiber, alternatively graphite fiber, carbon graphite or CF, is a material consisting of fibers about 5–10 μm in diameter and composed mostly of carbon atoms. The carbon atoms are bonded together in crystals that are more or less aligned parallel to the long axis of the fiber. The crystal alignment gives the fiber high strength-to-volume ratio (makes it strong for its size). Several thousand carbon fibers are bundled together to form a tow, which may be used by itself or woven into a fabric.
The properties of carbon fibers, such as high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion, make them very popular in aerospace, civil engineering, military, and motorsports, along with other competition sports. However, they are relatively expensive when compared to similar fibers, such as glass fibers or plastic fibers.
Carbon fibers are usually combined with other materials to form a composite. When combined with a plastic resin and wound or molded it forms carbon fiber reinforced plastic (often referred to as carbon fiber) which has a very high strength-to-weight ratio, and is extremely rigid although somewhat brittle. However, carbon fibers are also composed with other materials, such as with graphite to form carbon-carbon composites, which have a very high heat tolerance
(Wikipedia, Carbon Fibers, 6/7/2012)
“It is well known that, as a general rule, as the diameter of carbon fibers is decreased, strength generally increases. The reasons for this are usually ascribed to improved molecular orientation (e.g., increased graphitic structure) and to a reduction in the number of flaws due to the improved quality of the cross-sectional filament structure. At the extreme of the continuum lie carbon nanotubes, which ideally are fully graphitic without flaws in the structure of the walls. However, the realization of the potential of the mechanical benefits of these materials is hindered by the requirement of having to transfer load along the fiber length between fibers via mechanical entanglements caused by frictional and van der Waal's interactions between the carbon nanotubes themselves and between adjacent fibers through shear coupling such as from a matrix resin.
Currently, continuous carbon fibers with nanoscale features are not available except on the research level. Most carbon fibers with nanoscale features are either carbon nanotubes or carbon nanofibers. Carbon nanofibers are generally vapor-grown or electrospun. Vapor-grown carbon fibers typically comprise a range of lengths and are not continuous. By contrast, electrospun carbon fibers can be made continuously. However, there are many shortcomings to electrospinning.”
[Tsotsis, US Patent 8,187,700 (5/29/2012)]
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Roger D. Corneliussen
Maro Polymer Links
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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 6/7/2012.