Discovery can convert plant waste into carbon fiber for new products

An illustration of how plant waste can be converted into many products.

Image: Texas A&M AgriLife Research

Waste material from the paper and pulp industry soon could be made into anything from tennis rackets to cars.

“We have overcome one of the industry’s most challenging issues by discovering how to make good quality carbon fiber from waste,” said Joshua Yuan, a Texas A&M AgriLife Research scientist and an associate professor the Department of Plant Pathology and Microbiology, College of Agriculture and Life Sciences.

The research was published recently in Green Chemistry, the peer-reviewed journal of the Royal Society of Chemistry.

“People have been thinking about using lignin to make carbon fiber for many years, but achieving good quality has been an issue,” Yuan said.

About 50 million tons of lignin — the structural part of a plant — pile up each year as waste from the U.S. paper and pulping industry, he said. Additional lignin could come from biorefineries that use plants to produce ethanol, yielding another 100 million to 200 million tons of lignin waste each year. Yet only about 2 percent of the lignin waste is currently recycled into new products, Yuan said.

Lignin is a complex molecule, he said, but when the high-density, high molecular weight portion is separated from the rest, it has a uniform structure that allows the formation of high quality carbon fiber.

“We are still improving and fine-tuning the quality, but eventually this carbon fiber could be used for windmills, sport materials and even bicycles and cars,” he said. “Carbon fiber is much lighter but has the same mechanical strength as other materials used for those products now. This material can be used for a lot of different applications.

“The beauty of this technology is that it allows us to use lignin completely. Basically what we do is fractionate lignin so that the high molecular weight fraction can be used for carbon fiber and the low molecular weight fraction can be used use for bioplastics and products like asphalt binder modifier used on roads.”

More at Texas A&M AgriLife and the College of Agriculture and Life Sciences

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