Carbon fibers development

Figure 1 The status of carbon fiber development in 1984 based primarily on product data supplied by manufacturers. The solid line refers to commercial grades of fiber spun from mesophase pitch ( 7) the dashed line refers to an experimental mesophase fiber spun from solvent-extracted pitch (10). Experimental (noncommercial) fibers are indicated by triangular symbols.

J.E. Sheehan, J.T. Porter, C.H. Meyers, R.J. Price, R. Bacon, Coated Carbon Fiber Development for Oxidation Protection of Carbon-Carbon Composites, Interim Progress Report No. 10, Contract No. F33615-88-C-5449, MSNW, Inc., San Marcos, CA, 1990. 

Initial modern carbon fiber development occurred during 1944-1960 in the research and development Materials Laboratory of the Wright-Patterson Air Force Base (WPAFB), Dayton, OH, USA. The UK Royal Aircraft Establishment developed carbon fiber-RPs in the late 1950s. During this period carbon fiber produced from cotton and viscose rayon fabrics were principally used in military applications such as rocket nozzle cones and ablative surface panels on outer space vehicles (other fibers were also used). Barnaby-Cheney and National Carbon manufactured a small amount of carbon fiber from these fibers. 

Sibal, A.K. Carbon Fiber Development and Fabric Markets J. Coated Fabrics, 13, 206... 

Ko TH, Li CH, The influence of pre-carbonization on the properties of PAN-based carbon-fibers developed by 2-stage continuous carbonization and air oxidation, Polymer Composites, 16(3), 224-232, 1995. 

PAN-based carbon fibers develop exceptional tensile strength [in excess of 7000 MPa (23)] and are more resistant to compressive failure than high performance polymers (24). These factors combine to make PAN-based carbon fibers the ideal choice for applications requiring significant fiber strength. However, PAN-based fibers are less appropriate than mesophase pitch-based fibers for applications in which molecular order-dependent properties are key. 

OgawaH (2000), Architectural application of carbon fibers. Development of new carbon fiber reinforced glulam . Carbon, 38, 211-226. 

Aerospace struetwes made of composite. As part of the evaluation of the developed ultrasonic spectroscopy system the NSC software was tested on ultrasonic resonance spectra from composite panel samples. Spectra were collected with four different types of damages, and from flawless samples. The damages included a small cut in one of the carbon fiber... 

Acrylonitrile (AN), C H N, first became an important polymeric building block in the 1940s. Although it had been discovered in 1893 (1), its unique properties were not realized until the development of nitrile mbbers during World War II (see Elastomers, synthetic, nitrile rubber) and the discovery of solvents for the homopolymer with resultant fiber appHcations (see Fibers, acrylic) for textiles and carbon fibers. As a comonomer, acrylonitrile (qv) contributes hardness, rigidity, solvent and light resistance, gas impermeabiUty, and the abiUty to orient. These properties have led to many copolymer apphcation developments since 1950. 

Carbon and Graphite Fibers. Carbon and graphite fibers (qv) are valued for their unique combination of extremely high modulus and very low specific gravity. Acrylic precursors are made by standard spinning conditions, except that increased stretch orientation is required to produce precursors with higher tenacity and modulus. The first commercially feasible process was developed at the Royal Aircraft Fstablishment (RAF) in collaboration with the acrylic fiber producer, Courtaulds (88). In the RAF process the acrylic precursor is converted to carbon fiber in a two-step process. The use of PAN as a carbon fiber precursor has been reviewed (89,90). 

Electronic-Grade MMCs. Metal-matrix composites can be tailored to have optimal thermal and physical properties to meet requirements of electronic packaging systems, eg, cotes, substrates, carriers, and housings. A controUed thermal expansion space tmss, ie, one having a high precision dimensional tolerance in space environment, was developed from a carbon fiber (pitch-based)/Al composite. Continuous boron fiber-reinforced aluminum composites made by diffusion bonding have been used as heat sinks in chip carrier multilayer boards. 

For friction material appHcations, composite materials (qv) comprising glass or metallic fibers with other minerals have been developed. In such appHcations also, aramid and graphite fibers are effective, although the cost of these materials restricts their use to heavy duty or high technology appHcations (see Carbon fibers). 

Eurther heat treatment in excess of 2000°C is referred to as graphitization. Eiber stmcture further densifies as molecular packing and orientation increase. At temperatures of 3000°C or above, the fiber stmcture begins to approach a truly graphitic stmcture with three-dimensional order. Typically, fiber strain to failure decreases as the carbonization temperature exceeds 1500°C because of reaction of impurities with the carbon fiber and the development of an increasingly flaw-sensitive graphitic stmcture (31,34)... 

Further reduction in the price of carbon fibers may enable penetration into the automotive market. A primary carbon fiber producer has armounced that prices will drop to 700 yen/kg ( 6.80/lb) by 1995 (73) and that cooperative development efforts with a main Japanese automobile producer are underway. Development for use in constmction, such as cement and cable reinforcement, and marine apphcations will result in sustained growth volume through the eady twenty-first century. 

The original drive for the development of modem carbon fibers, in the late-1950s, was the demand for improved strong, stiff and lightweight materials for aerospace (and aeronautical) applications, particularly by the military in the West. The seminal work on carbon fibers in this period, at Union Carbide in the U.S.A., by Shindo, et al, in Japan and Watt, et al, in the U.K., is well-documented [4-7]. It is always worth pointing out, however, that the first carbon fibers, prepared from cotton and bamboo by Thomas Edison and patented in the U.S.A. in 1880, were used as filaments in incandescent lamps. 

It is appropriate at this stage to consider active carbons generally, before leading on to introduce active carbon fibers, which are a relatively recent development of these materials. 

Essentially, the technology of active carbon fibers is a combination of the technologies for carbon fibers and active carbons summarized above. This section is an outhne of the historical development of ACT. 

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