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2022-08-08 08:28:37 By : Ms. Echo Huang

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It's just as strong as Kevlar, but incredibly heat-resistant.

Scientists have a new material they say is as strong as Kevlar and way more insulating. The resulting fiber structure could protect first responders and military personnel who are in danger from heat and cold along with ballistic risks.

The existing problem is simple: To keep workers who require extreme protection safe, scientists must layer until they’ve covered all their bases. Why not protect two birds with one stony vest? The scientists write in their paper:

The process for making test sheets of the protective and insulating material involves technology that will sound familiar to lovers of, well, cotton candy. Researchers put the polymers into a device called an immersion Rotary Jet-Spinner (iRJS), where micro-fine strands are forced through a nozzle and then spun into gathered masses.

“Choosing para-aramid polymers as the building block, we engineered precursor solutions to be fluid-like during fiber spinning and solid-like during fiber formation,” the scientists explain. “This allowed for the fabrication of porous, continuous para-aramid fiber sheets (pAFS) with fiber diameters an order of magnitude lower than that of commercial para-aramid fibers.”

Starting with a liquid solution allowed for the spinning of the finest and most aerated fibers, which is how this material combines being lightweight and insulating along with ballistic protection.

Aramid stands for aromatic polyamide, a term that refers to the chemical structure of materials like this. In chemistry, being “aromatic” is a quality that allows molecules to be extremely stable due to a ringlike structure. Para-aramids in particular include Kevlar, the first para-aramid, and are even made into brake pads due to their extreme endurance and heat tolerance.

Dupont invented both Kevlar and a meta-aramid named Nomex, both of which form the basis for this research. The researchers explain:

The previous research that has enabled spinning new para-aramid mixes into gold is the adjustment of Kevlar fibers at the microscopic level. In a 2011 paper, scientists turned aramids into “a new nanoscale building block” that can be tweaked and hybridized for the best performance.

“Polymer nanofibers should be considered as essential ‘building blocks’ of the nanoscale toolset along with a large variety of inorganic ‘building blocks’ well known in materials science, which include nanoparticles, nanowires, carbon nanotubes (CNTs), graphene, and clay nanosheets,” those scientists explain.

Indeed, aerogels are one of the pinnacle building blocks: improbable and extraordinarily lightweight materials made by turning gases into gels. It’s the gel structure that boosts this new material’s heat insulation properties, and combining the strength and toughness of para-aramid fibers with the lightweight insulation of aerogel could mean a next generation of protective gear that’s lighter than air.