Friday, January 9, 2009

The Spectra vs. Kevlar Discusion

By Marcos Santana

In the last couple of years a lot of improvements have been made, especially in the police and military equipments and gear , improvements that have lead to better safety. The new bullet proof body armor is more comfortable and protective. In the past bulk and discomfort was part of being protected. Thanks to KEVLAR the new body armors for the police and military have greatly reduced weight and size.

Today, there is a new substance in use called Spectra, a composite material that is stronger, lighter, and more flexible than Kevlar, which is changing the face of bullet proof wear for our troops and police forces. What are the major differences between Kevlar and Spectra, and what are the big advantages of the latter?

If we examine the structure of the two we see that Kevlar is made from a high strength and high performance fiber who's properties are not yet entirely understood despite the fact that it has been used in bullet proof clothing for many years. A more or less exact description is difficult but you should try to see it is that the molecules form into sheets that then stack themselves around the center of a fiber like spokes. Stacking together several layers of Kevlar in a woven pattern creates the bullet proof material.

The weaving would then "catch" the bullet by allowing the fibers to break apart layer by layer and absorb the velocity, slowing the bullet to a stop as it also dulled and flattened from striking the material. However, this was mostly effective when bullets were slower and had less total velocity, making them easier to stop. Now, our troops and law enforcement officials face much more technically advanced weaponry with bullets flying at higher speeds and constructed from harder metals.

This means that Kevlar vests are stretched to capacity and sometimes even penetrated completely by these forceful weapons. The only answer with this material is to thicken the layers of weave, which make the material even bulkier, heavier, and less flexible.

Spectra is a completely new and different technology. Spectra is about 40% lighter than Kevlar which makes it a lot more comfortable. Spectra is not been woven which only helps reducing even more the weight and bulk as there is no need for several layers. - 16492

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