Carbon fiber-reinforced plastic (CFRP), also known as carbon fiber-reinforced polymer, is a product that has gotten the attention of automobile manufacturers in recent years due to the high-strength and lightweight properties it brings to the table.
The automotive industry’s constant challenge to meet ever-changing fuel economy standards makes materials of lighter weight more attractive than ever before. In fact, CFRP is 50 percent lighter than steel and 30 percent lighter than aluminum. Add to this the fact that it can be up to 10 times stronger than steel and its use becomes even more compelling.
CFRP Becoming Common
CFRP materials have been used in high-end auto racing applications for several years but, except for prototypes, its use in passenger vehicles has been limited because of its high cost. Technological improvements in the manufacturing process, however, are making its use in high-volume manufacturing more cost effective. In addition to an impressive strength to weight ratio, there are some safety advantages associated with making cars with CFRP material. It can absorb up to 12 times more crash energy than steel. CFRP also has many recycling opportunities, so it has benefits at the beginning of its life along with the end.
BMW is leading the way in the passenger car market by using carbon fiber-reinforced plastic material in its new i-series vehicles. The product is becoming more widely used in the airline industry with Airbus using it to reduce weight. Many ultralight planes are built with the material in order to stay below the weight limits that are required for ultralight aircraft.
Carbon fiber-reinforced plastic is a composite material that is a combination of carbon fiber and lightweight plastic. The finished product is many times stronger than either component could ever be on its own. The manufacturing process begins with spinning carbon filament into filament yarn, which is then woven into a sheet. Layers of these sheets are then placed into a mold. The mold is then filled with epoxy to form the finished product. An alternative method for manufacturing CFRP is through compression molding, whereby high pressure stamps the mixture into the desired shape.
As the use of CFRP materials becomes more widespread in the automobile industry, more thought will be given regarding the end-of-life phase of the material. In other words, is there a beneficial use for CFRP after the vehicle in which it was used is no longer in service? The answer lies in recycling opportunities. The simpler of the two primary means of recycling the material is to shop it into smaller pieces and send it to a manufacturer who can use it in another type of product. After it is cut into small pieces, the carbon fiber is no longer intact. This means it cannot be used to make another item that yields the same strength as the original. In this situation, however, there is still a beneficial use opportunity. For example, the material could be used for door panels or other components in which strength is not a critical factor.
Pyrolysis is a method by which carbon fiber-reinforced plastic can be recycled in a way that leaves the carbon fiber intact. The plastic in the material is vaporized and the remaining carbon fiber can then be used to make a product in which strength is important.