Composites, advanced carbon

Airbus A380 structure uses 25 % of advanced composites. Carbon fibre reinforced plastics (CFRP) are used for about 22% of the airframe. 

Carbon (sometimes referred to as graphite) fibre is the reinforcement material of choice for advanced composites. Carbon fibres have a higher fatigue resistance than glass or aramid. 

Carbon (sometimes referred to as graphite) fibre is the reinforcement material of choice for advanced composites. Carbon fibres have a higher fatigue resistance than glass or aramid. Carbon fibre properties depend on the structure of the carbon used and are typically defined as standard, intermediate and high modulus fibres. Several thousand fibres are twisted together to form a yarn which may be used by itself or woven into a fabric. The yarn or fabric is combined with a resin, usually epoxy, and wound or moulded to shape to form a wide variety of products. 

Composites. High molecular weight PPS can be combiaed with long (0.6 cm to continuous) fiber to produce advanced composite materials (131). Such materials having PPS as the polymer matrix have been developed by usiag a variety of reinforcements, including glass, carbon, and Kevlar fibers as mat, fabric, and unidirectional reinforcements. Thermoplastic composites based on PPS have found application ia the aircraft, aerospace, automotive, appliance, and recreation markets (see Composite materials, polymer-matrix). 

J. D. Buckley, ed.. Advanced Materials, Composite Carbon, Preparation Symposium, American Ceramics Society, Inc., Columbus, Ohio, 1972. Papers on composite materials including carbon and graphite or nitride composites. 

More than 95% of current carbon fiber production for advanced composite appHcations is based on the thermal conversion of polyacrylonitrile (PAN) or pitch precursors to carbon or graphite fibers. Generally, the conversion of PAN or pitch precursor to carbon fiber involves similar process steps fiber formation, ie, spinning, stabilization to thermoset the fiber, carbonization—graphitization, surface treatment, and sizing. Schematic process flow diagrams are shown in Eigure 4. However, specific process details differ. 

Because of this continued emphasis on adhesive bonding technology development over the years, the airframes of modem front-line aircraft such as the B-2 bomber and the F-117 and F-22 fighters are largely structurally bonded advanced composites. They tend to be comprised of materials that are more advanced (expensive) than commercial aircraft such as carbon and boron fiber reinforcements with cyanate esters, bismaleimides, polyimides or other high-temperature resin matrices and adhesives. 

The aeronautics sector is a significant composite consumer, particularly in terms of turnover, because of the high proportion of advanced composites used with matrices such as epoxies, polycyanates, polyimides, PEEK, and reinforcements such as carbon fibres. 

For the global advanced composites market, the average cost of high-performance fibre reinforcements (carbon, aramid, high modulus polyethylene, boron, R/S/T-glass and some E-glass) is estimated from 5.5 to 6 per kg. This moderate price is due to the decrease in the carbon fibre price. Some grades could fall to less than 10/kg in the short or medium term. 

Dieffendorf, R. J. (1985). Comparison of the various new high modulus fibers for reinforcement of advanced composites with polymers, metals and ceramics as matrix, pp. 46-61. In Fitzer, E. ed. Carbon Fibers and Their Composites, Springer-Verlag, New York. 

Addition poly(imide) oligomers are used as matrix resins for high performance composites based on glass-, carbon- and aramide fibers. The world wide market for advanced composites and adhesives was about 70 million in 1990. This amounted to approximately 30-40 million in resin sales. Currently, epoxy resins constitute over 90% of the matrix resin materials in advanced composites. The remaining 10% are unsaturated polyester and vinylester for the low temperature applications and cyanate esters and addition poly(imides) for high temperatures. More recently thermoplastics have become important and materials such as polyimides and poly(arylene ether) are becoming more competitive with addition polyimides. 

An important breakthrough in the development of advanced composites came in the late 1960s the invention of boron and carbon filaments in the United States, the United Kingdom, and Japan. These fibers were soon incorporated into some of the earliest... 

Lau, K.T., Hui, D., Effectiveness of using carbon nanotubes as nano-reinforcements for advanced composite structures, Carbon, 40, 2002, 1597-1617. 

Chemical vapor infiltration (CVI) is widely used in advanced composites manufacturing to deposit carbon, silicon carbide, boron nitride and other refractory materials within porous fiber preforms. " Because vapor phase reactants are deposited on solid fiber surfaces, CVI is clearly a special case of chemical vapor deposition (CVD). The distinguishing feature of CVI is that reactant gases are intended to infiltrate a permeable medium, in part at least, prior to... 

The observational constraints on the solar isotopic abundances of oxygen are also poor. The only solar-wind measurement, by the Advanced Composition Explorer, yielded a ratio of consistent with the terrestrial value, with 20% uncertainty (Wimmer-Schweingruber et al., 2001). An earlier spectroscopic measurement of the solar photosphere gave a similar result (Harris et al., 1987). No information is available on the solar abundance. The very limited state of knowledge of the solar isotope abundances of carbon, nitrogen, and oxygen illustrates the importance of the NASA Genesis mission to collect a pure solar-wind sample and return it to Earth for laboratory measurement. 

Organic matrices are divided into thermosets and thermoplastics. The main thermoset matrices are polyesters, epoxies, phenolics, and polyimides, polyesters being the most widely used in commercial applications (3,4). Epoxy and polyimide resins are applied in advanced composites for structural aerospace applications (1,5). Thermoplastics Uke polyolefins, nylons, and polyesters are reinforced with short fibers (3). They are known as traditional polymeric matrices. Advanced thermoplastic polymeric matrices like poly(ether ketones) and polysulfones have a higher service temperature than the traditional ones (1,6). They have service properties similar to those of thermoset matrices and are reinforced with continuous fibers. Of course, composites reinforced with discontinuous fibers have weaker mechanical properties than those with continuous fibers. Elastomers are generally reinforced by the addition of carbon black or silica. Although they are reinforced polymers, traditionally they are studied separately due to their singular properties (see Chap. 3). 

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