Researchers in Singapore have developed a process for converting carbon fiber composites waste (including both the fiber and resin) into aerogels with potential uses in insulation, sound absorption and oil spill clean-up. The method, reported by The Engineer and detailed in Waste Management, was developed by a team led by associate professor Duong Hai Minh of the National University of Singapore’s (NUS) Department of Mechanical Engineering.
Conventional recycling approaches often concentrate on recovering carbon fibers only, while discarding, destroying or recovering the matrix resin as a lower-value material. Some recycling processes also involve high temperatures, chemicals or significant energy consumption.
NUS researchers instead mechanically processed composite waste into a mixture containing fine particles and short fiber fragments and combined this material with carboxymethyl cellulose, a cellulose-derived binder, before freeze-drying it. This produces an aerogel with a lightweight, porous structure. The interconnected pores contain a high proportion of air, helping to restrict heat transfer through the material.
Laboratory testing has shown that the resulting aerogels have low thermal conductivity, indicating potential applications as lightweight thermal insulation. Researchers also found that the material could absorb sound.
“Our goal was to show that carbon fiber composite waste does not have to be treated only as a disposal problem,” Duong says. “By using the whole material, including both the fiber and epoxy fractions, we can turn this waste stream into functional materials with higher value.”
The team also modified the aerogels to make them water-repellent and capable of absorbing “substantial quantities of oil,” thereby giving them utility in oil spill response.
Tests using fibroblast cells found no toxicity under the conditions examined in the study. Findings provide a basis for further investigation of applications where the material could come into contact with people or the environment, and researchers are now looking at potential collaborations with organizations in aerospace, advanced materials, manufacturing and waste management. Further work will examine how the process can be scaled and assess its environmental and economic performance at industrial scale.
Ngo Minh Quang Phan (left), first author of the study, and associate professor Duong Hai Minh (right), who led the research, with a carbon fiber/epoxy aerogel developed by the NUS team. Source | NUS
