Fiber Reinforcement and Architecture

3-D textile preforms [3-6] are particularly important for shaping a reinforcement prior to inclusion in, say, RTM and carbon arbon composites. 

Since carbon fiber is electrically conductive, it is good practice for processors working with carbon fiber, to have designated work areas set aside, so that all electrics can be adequately protected from carbon liber fly and an efficient air filtration system built into the workplace to safeguard operatives. Oxidized PAN fiber is not electrically conductive, however, and does not have these problems. 

With carbon reinforcements, it is possible to incorporate two or more different yarns (e.g. an aramid and carbon, or glass and carbon), to form a hybrid carbon reinforcement, enabling a designer to incorporate properties into a composite that fall between the performance levels of the chosen fibers. So the introduction of an aramid fiber into a carbon fabric reinforcement would improve the impact resistance, albeit at the expense of other mechanical properties. Special scissors are available to cut aramid fibers. 

A tow of carbon fibers is a plurality of non-twisted continuous carbon filaments, about 5-10 pm in diameter, with typical tow sizes of 3A , 6k and 2k, normally surface treated and sized. Larger and less expensive carbon fiber tows, such as 24k, 4Qk, 4%k, 80A , 6Qk, 3 2Qk, 400A and 410A (Tables 20.3, 20.4) are now becoming more widely available. 

Adhesive Heat Bonded Needled Milled bonded fusion web mat fiber chopped strand mat(crm), 

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