Can Kevlar Be Replaced by Something Even Stronger?

These spun nanofibers are stronger than Kevlar. (Image: www.pinterest.com)
These spun nanofibers are stronger than Kevlar. (Image: www.pinterest.com)

Is their something tougher then Kevlar? The answer is yes. Researchers at the University of Texas in Dallas have made a material that will stretch to up to seven times its own length, while remaining stronger than Kevlar, using nanofibers.

Kevlar is used to make bulletproof vests, among other things. It has a capacity to absorb up to 80 joules per gram before breaking. This new material can absorb up to 98 joules per gram before breaking, which makes it even stronger. The researchers hope that one day this material will be able to reinforce itself at points of high stress to be used by the military in aircraft or other defense applications.

Dr. Majid Minary, an assistant professor of mechanical engineering, was senior author of the study.  Image: University of Texas, Dallas

Dr. Majid Minary, an assistant professor of mechanical engineering, was senior author of the study.
(Image: University of Texas, Dallas)

The study was published by ACS Applied Materials and Interfaces, which is a journal of the American Chemical Society.

The researchers twisted the nanofiber into yarns and coils. The electricity that was generated by stretching the twisted nanofiber formed an attraction that was 10 times stronger than a hydrogen bond. A hydrogen bond is considered to be one of the strongest forces formed between molecules.

nanofiber Image: aslamacia/Wikimedia Commons

Nanofiber filaments.
(Image: aslamacia/Wikimedia Commons)

Dr. Majid Minary,  an assistant professor of mechanical engineering at the University’s Erik Jonsson School of Engineering and Computer Science, said that they  were trying to replicate their earlier work on the piezoelectric action (how pressure forms electric charges) of collagen fibers that is found inside bone in hopes of creating a high-performance material that could reinforce itself.

“We reproduced this process in nanofibers by manipulating the creation of electric charges to result in a lightweight, flexible, yet strong material,” said Minary, who is also a member of the Alan G. MacDiarmid Nanotech Institute and senior author of the study.

Our country needs such materials on a large scale for industrial and defense applications.

The researchers first spun nanofibers out PVDF and its co-polymer, polyvinvylidene fluoride trifluoroethylene (PVDF-TrFE). Researchers then twisted the fibers into yarns, and then continued to twist the material into coils.

Researchers were then able to measure the mechanical properties of the yarn and coils, e.g., how much energy it can absorb before failure, and how far it can stretch.

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“Our experiment is proof of the concept that our structures can absorb more energy before failure than the materials conventionally used in bulletproof armors,” Minary said. “We believe, modeled after the human bone, that this flexibility and strength comes from the electricity that occurs when these nanofibers are twisted.”

The next step in the research will be to make larger structures out of the yarns and coils, Minary said.

This material has many potential uses, especially for the military and police forces.

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