Monday, April 11, 2011

Wool added to body armor

Researchers at the Royal Melbourne Institute of Technology (RMIT) school of fashion and textiles discovered that a blend of wool and Kevlar, the synthetic fiber widely used in body armor, was lighter and cheaper and worked better in some conditions than Kevlar alone.

The RMIT textile technologist, Rajiv Padhye, Ph.D., said the standard bullet proof vest was generally made of Kevlar, a dense, strong and expensive fiber. For military use, a heavy ceramic plate provides greater protection over vital areas.

A Kevlar vest typically comprises some 36 layers of Kevlar fabric; however, it loses about 20 percent of its effectiveness when wet, requiring an expensive waterproofing process.

"What we did was kept the Kevlar but added a wool yarn into this," he said. The increased friction of the wool in a tight weave means a vest comprising 28-30 layers of fabric provides the same level of bullet resistance as 36 layers of Kevlar.

"Because wool fibers expand naturally in water by up to 16 percent, the wool-Kevlar blend actually becomes more effective in wet conditions," he said. "The result is a cheaper bullet-resistant vest that works even better when it's wet."

That's a significant matter, considering Kevlar costs about $70 a kilogram compared with about $12 a kilogram for wool.

Source:  ASI Weekly, 4.08.11
(reprinted in part from Australian Associated Press)

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