By: Masayuki Fujita and George Okada
It is well known that Carbon Fiber-Reinforced Plastic (CFRP) has attractive features like high-durability, high-strength and light-weight. These features have been stimulating the CFRP to be applied for a wide variety of applications. For example, by using the CFRP as a body material of aircrafts and automobiles, higher fuel efficiency and hence lower carbon emissions in transportations has been realized. Also, in sports and recreation, items such as fishing rods, golf club shafts and tennis rackets heavily incorporate CFRP.
There are two types of carbon fibers (CFs), PAN-type and Pitch-type (http://www.carbonfiber.gr.jp/english/ material/type.html). The PAN-type CF, which is almost amorphous carbon, has high tensile strength and high elastic modulus and is commonly applied for structural material composites. On the other hand, the Pitch-type CF, which is almost graphite, has ultra-high elastic modulus and is adopted in high stiffness components such as robot arms to handle large glass panels. Anisotropic Pitch-type CF has very high thermal conductivity (200-800W/mK), which is comparable to or higher than copper. Furthermore, the coefficient of thermal expansion of the Pitch-type CFRP is extremely low (-1.3×10-6℃), which is advantageous to dimensional stability in high temperature environments.