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Polyethylene Bulletproof Vests Better Than Kevlar
teflonscout writes "When I think of bulletproof vests, the first word that comes to mind is Kevlar. Wired is running a story on Dynema SB61, a bulletproof material that is made of polyethylene. It is a higher grade of the plastic found in Tupperware. The story also mentions the recall of Second Chance bulletproof vests that were made from Zylon, a material that degraded slowly when exposed to moisture. At least one police officer was injured when a bullet penetrated his Zylon vest. Polyethylene is impervious to moisture. The first vests made from this new material are 5mm thick and can stop a 9mm bullet traveling at 1777 feet per second, which is slightly better than other top of the line vests."
Dynema SB61, a bulletproof material that is made of polyethylene. It is a higher grade of the plastic found in Tupperware.
There goes my idea for a zip-tie & Tupperware bulletproof vest. It also explains why the prototypes failed in the field.
Trolling is a art,
Can't wait to see The Box O' Truth give it a try.
Do they burp when they're hit?
If you haven't heard about the history of "second chance" one of the very first commercial vest manufacturers, that is basically how they sold it. Walk into a police station, pull a gun, shoot oneself at point blank. Put the gun, vest, and business card on the front desk and walk out. As I understand they arrested the founder (Richard Davis) for firing a pistol within city limits, and placed a huge order. He eventually had to quit doing it because all the bruises from the gunshots were starting to give him heart problems.
If it's basically like wearing a big plastic slab, isn't that going to get super hot?
That's why you lacquer the chestplates in white to dissipate heat, and give them a black spandex bodysuit underneath...add a scary looking helmet and most of your vitals are covered. In theory it should deflect blaster bolts. Where I'm stationed we wear them all the time (I work in law enforcement).
In practice, they don't stop crap. Like last week this scruffy-looking nutjob with a walking carpet for a sidekick breaks in to rescue his girlfriend. Next thing we know there's a weapons malfunction down in the cell block, and four of my buddies find out the chestplates don't quite work as advertised.
I hate this posting...maybe I can get transferred before something else goes wrong.
- TK421
Study everything, you'll find something you can use - Jason Bourne
Because if you carry less weight in body armor, you carry more weight in ammunition, med supplies, whatever. The protection they have today is generally sufficient for small arms rounds, so they don't usually need more protection. Reducing the weight of current equipment, however, goes a long way toward making your troops more mobile, responsive, and better prepared to face an enemy. Not to mention, it makes them feel better to not lift a 35 pound vest over their head.
I've worn the modern vests, and while they aren't nearly as bad as they were 10 years ago, they still aren't good. If I could get the same protection from something even a quarter less weight, I'd make the switch without a second thought. That two or three extra pounds can mean the difference of being able to march my ass another couple of kilometers to safety or have a few extra rounds of ammunition when I really need it. That's a huge mental advantage, and despite all we say about war, it's the mental aspects (on the soldier) that make it difficult in the long run.
"Growing old is inevitable; growing up is optional."
This is one of those cases where allegory is truly misleading. The article makes the comparison to shopping bags and tupperware in order to emphasize the "everyday" nature of the material. The truth is that they have similar basic components, but the exact composition and processing differences cause one material to be good at resisting bullets and another at storing food (or selling at parties.) Unlike Tupperware, Dyneema vests are composed of woven and laminated fabric.
Dyneema is actually a trade name for a thread derived from Ultra High Molecular Weight polyethylene. The intrinsic strength of the material comes from the ability to increase the length of the polyethylene chain to extreme lengths. Since the structure of UHMW derives its strength mostly from the intermolecular Van-der Waals forces, the longer the polythethylene chains get, the stronger the forces holding the material together become. When the processing of the polythylene allows the length of the chains to become uniform, then you can engineer it into useful forms, such as a fiber which eventually be formed into fabric, then laminated and put on your chest.
Of course, being UHMW, Dyneema has a weakness: Its melting point is about 300 degrees Fahrenheit, or about the temperature of a hot light bulb. Which means that while your body heat might not harm the vest, carelessness in storage might.