Fiber medicine

Healable carbon fiber composite paves the way for durable, long-lasting materials – sciencedaily

Due to their high strength and light weight, carbon fiber composite materials are gradually replacing metals to advance all kinds of products and applications, from airplanes and wind turbines to golf clubs. But there is a compromise. Once damaged or compromised, the most commonly used carbon fiber materials are nearly impossible to repair or recycle.

In an article published on November 2 in the journal Carbon, a team of researchers describes a new type of carbon-fiber-reinforced material that is as strong and lightweight as traditionally used materials, but can be repeatedly healed with heat, reversing any damage from fatigue. This also allows it to be broken down and recycled when it reaches the end of its life.

“The development of fatigue-resistant composites is a major need in the manufacturing community,” said co-lead author Aniruddh Vashisth, assistant professor of mechanical engineering at the University of Washington. “In this paper, we demonstrate a material in which traditional heat sources or radio frequency heating can be used to reverse and postpone its aging process indefinitely.”

The material is part of a recently developed group known as carbon fiber reinforced vitrimers, named after the Latin word for glass, which exhibit a mixture of solid and fluid properties. The materials most commonly used today, whether in sporting goods or in the aerospace industry, are polymers reinforced with carbon fibers.

Traditional polymers reinforced with carbon fibers generally fall into two categories: thermosets or thermoplastics. The variety “set” contains an epoxy, a glue-like material where the chemical bonds that hold it together harden permanently. The “plastic” version contains a softer type of glue which can therefore be remelted and reworked, but this becomes a disadvantage for high strength and rigidity. Vitrimers, on the other hand, can bind, dissociate, and reconnect, providing a happy medium between the two.

“Imagine each of these materials being a room full of people,” Vashisth said. “In the thermosetting room, everyone holds hands and does not let go. In the thermoplastic room, people shake hands and move around. In the vitrimer room, people shake hands with their neighbor but they have the ability to swap handshakes and create new neighbors so that the total number of interconnects stays the same. This reconnection is how material is repaired and this article was the first to use scale simulations atomic to understand the mechanisms behind these chemical handshakes.

The research team believe that vitrimers could be a viable alternative for many products currently made from thermosets, which is badly needed as thermosetting composites have started to pile up in landfills. The team says healable vitrimers would be a major shift to a dynamic material with a different set of considerations in terms of life cycle cost, reliability, safety and maintenance.

“These materials can translate the linear life cycle of plastics into a circular cycle, which would be a big step towards sustainability,” said lead co-author Nikhil Koratkar, professor of mechanical, aerospace and nuclear engineering at the Institute. Rensselaer Polytechnic.

The research team also includes Mithil Kamble and Catalin Picu at the Rensselaer Polytechnic Institute and Hongkun Yang and Dong Wang at Peking University of Chemical Technology. This research was funded by the U.S. Army and NASA through the Vertical Lift Research Centers of Excellence, the National Science Foundation, the John A. Clark and Edward T. Crossan Chair of the Rensselaer Polytechnic Institute, the ‘University of Washington and Society. Software for chemistry and materials.

Source of the story:

Material provided by Washington University. Original written by Andy Freeberg. Note: Content can be changed for style and length.