Researchers discover new way to recycle carbon fiber waste

A team of researchers from Shanghai Jiao Tong University has developed a new technology and equipment for recycling carbon fiber composite waste material.

Carbon fiber is often described as "the king of new materials" and is mostly used in the manufacture of spacecraft, aircraft, communication satellites and other cutting-edge technologies. It is also widely used in cars, bicycles, tennis rackets and fishing rods.

There are about 60 to 70 kilograms of carbon fiber in every 100 kg of aviation carbon fiber composite waste material. The total amount of carbon fiber composite waste material in the world is expected to reach 50,000 metric tons by 2020. Of that total, the amount of carbon fiber will exceed more than 25,000 tons and will be worth more than 5 billion yuan ($760 million), according to experts.

"The carbon fiber in the composite waste material still has a high recycling value, but in actual operations it is very difficult to regenerate the carbon fiber. This is a bottleneck in the further development of composite materials," said Yang Bin, an associate professor at the School of Chemistry and Chemical Engineering at Shanghai Jiao Tong University. The commonly used carbon fiber composite material is mainly composed of carbon fiber and thermosetting resins, which is insoluble and nonfusible. In the past, the carbon fiber composite waste material were processed by burying or burning it, but which led to environmental pollution. Dumping or burning it is currently banned by the Chinese government.

The task of regenerating carbon fiber from the material waste and recycling the thermosetting resins in the form of energy or useful material is the challenge ahead, Yang said.

And after five years, the team has discovered a method to accomplish exactly that. The team developed a technology that allows the material waste to be processed in large chunks, without the need to cut or grind them into small pieces. The result is a regenerated carbon fiber that is longer.

The technology can be undertaken on a large-scale operation, with annual processing capacity exceeding more than 200 tons. Earlier, only three companies in Germany, Japan and the United States had an industrialized technology for recycling carbon fiber composite waste material.

Thus far, the technology from Shanghai Jiao Tong University's researchers has been listed in the 2015 automotive industry standards to guide the recycling and reuse of automotive materials by the China Automotive Technology and Research Center.

"The country has been actively promoting the application of carbon fiber composite materials. The new technology has taken into account the need to reuse resources and protect the environment, which will play a positive role for the economy's sustainable development," said Yi Xiaosu, director of the State key laboratory of advanced composite material at Beijing Institute of Aeronautical Materials.

wanghongyi@chinadaily.com.cn