Carbon-fiber-reinforced polymer
Fiber Type: carbon fiber HT Matrix Type: Epoxy Fiber volume fraction of 60 % All values are typical Averages
Carbon fiber -reinforced plastic, also CFRP ( carbon fiber reinforced plastic, english carbon -fiber- reinforced plastic, CFRP ) or colloquially known only Carbon (English for carbon), is a fiber reinforced polymer composite material, in which carbon fibers, usually in several layers, as reinforcement are embedded in a plastic matrix.
The matrix consists mostly of thermosets, such as epoxy resin, or thermoplastic. For thermally highly stressed components (eg brake discs ), the carbon fiber can also be bound in a matrix of ceramic (see ceramic fiber composites).
Description
In the manufacture of carbon fiber, a high fiber volume fraction is desired, said impurities, for example by air bubbles should be minimized. The modulus of elasticity (E modulus ) of the fiber must be higher than that of the matrix material. The matrix must adhere to the fiber, otherwise fail the components due to fiber pull-out.
The strength and stiffness of a material made of carbon fiber is, as with all the fiber-matrix composites, the grain is much higher than transverse to the fiber direction. Transverse to the fiber, the strength is lower than that of an unreinforced matrix. Therefore, individual fiber layers are laid in different directions. In high-performance construction components, the fiber directions by the designer using a computer calculation can be specified ( eg, by using the classical laminate theory ) in order to achieve the planned strength and rigidity.
CFRP is used when high weight-specific strength and stiffness are required, such as in the aerospace, automotive or sports equipment such as bicycle frames, speed skates, tennis rackets, sports arrows and fishing rods. In construction, CFRP is used as the reinforcement of concrete structures or bonded in the form of lamellae superficial or into slots on the component surface to reinforce structures.
Manufacturing process
The manufacturing processes are similar to those of glass fiber reinforced plastic (GRP) and require a high degree of manual work. It mainly processes are used, with which high-quality fiber composites can be produced ( in the press or autoclave prepreg, filament winding ). CFRP laminates are hand against it almost exclusively in Kleinserienbau and in the individual production for use.
When used as a plastic matrix phenolic resin and the matrix then, at temperatures of 800-900 ° C under an inert gas (nitrogen) is pyrolyzed, a new class of materials, the carbon fiber reinforced carbon can (german carbon -fiber- reinforced carbon, CRC and CFRC ), developed be. Phenolic resin in this case is a carbon yield of> 50 wt - %, whereby a porous carbon matrix is formed. This is reinforced by the carbon fibers. By repeated impregnation and pyrolysis of phenolic resin or other materials with a high carbon yield, for example, liquid Peche, the porous portion can be filled and the carbon matrix can be made denser with each impregnation and pyrolysis.
The porous matrix structure can also be filled by a gas phase pyrolysis of carbon-containing gases. However this process is more protracted than the liquid phase infiltration process with subsequent pyrolysis.