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Science Hardware

Polyethylene Bulletproof Vests Better Than Kevlar 345

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."
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Polyethylene Bulletproof Vests Better Than Kevlar

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  • by froggero1 ( 848930 ) on Wednesday May 23, 2007 @02:33PM (#19242101)
    it's not really a bad idea to step away from kevlar... of course assuming that it still stops bullets.

    my question though, will it weigh less than kevlar? every chunk of kevlar that i've held (my father made vests for a while) was extreamly heavy... I'd say if this substance is lighter and allows for more agility it just might be worth it, but again, let's not jepordize safety for mobility
  • by Timesprout ( 579035 ) on Wednesday May 23, 2007 @02:43PM (#19242329)
    And more importantly how does it compare with the secondary injuries caused by the impact of the bullet. One of the issues with modern vests is that you can still receive substantial injuries when the vest hits you after the bullet hits it.
  • by YourMotherCalled ( 888364 ) on Wednesday May 23, 2007 @02:47PM (#19242405)
    The correct term is bullet-resistant.
  • by AP2k ( 991160 ) on Wednesday May 23, 2007 @02:51PM (#19242493)
    Regardless, you could take down a police officer if he was wearing inch thick steel plating by just hitting him in the face. Might not be quite as mortal as a shot to the heart, but he is at least out of the fight. Alot of good modern kevlar does against headshots, huh? Not to mention you can do it with any gun and a rock if you throw it hard enough.
  • by AutopsyReport ( 856852 ) on Wednesday May 23, 2007 @02:53PM (#19242521)
    Rather, flame the complete ignorance of the process by which new technologies trickle down to soldiers from the numerous trials and tests...If it's good enough, it will eventually be used.

    Not quite. There's a lot of good products that should be used, but they aren't because of the almighty dollar. Usually it takes a few dead bodies, the tears of weeping mothers, pointed fingers, and fistfuls of public rage to force the government to supply adequate equipment to its troops. And even then they only supply it because of public image.
  • by bkr1_2k ( 237627 ) on Wednesday May 23, 2007 @03:11PM (#19242773)
    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.
  • by Ajehals ( 947354 ) <> on Wednesday May 23, 2007 @03:15PM (#19242849) Homepage Journal

    let's not jepordize safety for mobility
    Overall saftey is a trade-off of both protection and mobility.
  • by IndustrialComplex ( 975015 ) on Wednesday May 23, 2007 @03:28PM (#19243039)
    Of course, it is great marketing to show that your body armor can stop all rounds up to a 30mm A-10 round, but what LEOs really need is something a bit less.

    If I could invent two types of armor, one that worked against a 30mm round, but looked like the bomb disposal suit, and a piece of armor that only worked against 22 caliber rimfire, but looked and felt identical to a cotton T-shirt; the Tshirt-like armor would be the real success.
  • Re:Etcetera (Score:2, Insightful)

    by p!ssa ( 660270 ) * on Wednesday May 23, 2007 @04:01PM (#19243573)

    How much is your life worth to you, and what's the chance of you losing it to a bullet? There's the demand side value. It will be close to that.
    No, thats not right. The question is how much is your life worth to the current political establishment.., or just ask all of the the guys standing around in Iraq with no body armor.
  • Re:Box Of Truth (Score:4, Insightful)

    by Akaihiryuu ( 786040 ) on Wednesday May 23, 2007 @04:47PM (#19244347)
    There's another factor here too that many people don't consider. Even if the vest *were* to completely stop the penetration of a high powered rifle round, there would still be severe injuries to the person. All the kinetic energy from the bullet has to go somewhere...the vest may stop penetration but all that energy can't just mysteriously disappear. That's why when someone gets hit with a high powered round, even if the vest completely stops the bullet, they often get burns, bruises, and sometimes broken bones. There's no way around this until someone invents inertial dampeners.
  • Re:Etcetera (Score:3, Insightful)

    by petermgreen ( 876956 ) <plugwash @ p> on Wednesday May 23, 2007 @04:54PM (#19244445) Homepage
    I personally think we are maybe 10 years away from finding an impenetrable body armor solution.
    I somewhat doubt it.

    on the one hand you have companies developing armor on the other you have companies developing weapons. Armour manufacturers will reasearch what the weapon manufacturers are doing and vice-versa and attempt to counter it and users of the equipment will just adjust what proportion of thier weight or financial budgets they spend on each so that the armour on the battlefield stays balanced with the weapons on the battlefield.

  • by Phase Shifter ( 70817 ) on Wednesday May 23, 2007 @06:55PM (#19245913) Homepage
    The question is, would you want to use this in Iraq? If anything, the two words I generally hear used to describe that region are "hot" and "dry".

    Polyaramid fibers like kevlar may lose strength when they get wet, but polyethylene generally doesn't tolerate heat very well.

  • by maxume ( 22995 ) on Wednesday May 23, 2007 @07:32PM (#19246321)
    A good way to stay inside the boundaries of the international rules of war(the giant compendium of questionable facts says that bullet rules are generally from the Hague conventions: 99_and_1907)) [] is to use full metal jacket ammunition. This ammunition is also good for piercing armor. As someone who has never been shot, I'm willing to bet a serious amount, like a dollar, that if you ask someone who had been shot with FMJ and with other ammunition, that they would rave about what a wonderful experience the FMJ was, as it tends to go right through things, rather than mushrooming into a two inch wide circle of shrapnel and tearing things to shreds.

    As crazy as it is to have rules about shooting at each other, the ones that exist have good reason.
  • by mabhatter654 ( 561290 ) on Wednesday May 23, 2007 @11:26PM (#19248119)
    he was agreeing with you. If a kevlar vest sinks it's one more thing you have to swim against (the Navy works in the high seas after all) But the shrapnel is probably a bigger concern as most ship to ship warfare is missiles now anyway. As a sailor they're not even gunning for YOU anymore, but when your dealing with guns that split steel beams people are pretty fragile creatures. The flying scraps would take out most people easily.

    I'd think the difference is that the poly absorbs more energy thru phase change than the kevlar does. Kevlar acts as a net to stop the bullet getting thru by tightening up. The fibers themselves don't absorb damage, just spread it out. Poly being slightly weaker would absorb the energy of the bullet thru generating heat that breaks up the molecules... sounds counter intuitive, but that heat has to come from kinetic energy... or something like that. The same reason bicycle helmets are mostly styrofoam and not steel... it's the body underneath that's fragile, safety gear can be replaced for minimal cost over the cheapest GSW surgery.

  • by Ganesh999 ( 1075569 ) on Thursday May 24, 2007 @07:58AM (#19250751)
    The dispute on effectiveness is irrelevant.

    I R'dTFA. My suggestion :

    "It's simply a question of weight. Standard armour weighs 28lbs; Dragonskin weighs 47lbs. Despite increased flexibility and arguably better protection, our people can't operate effectively or safely under that penalty - their mobility, stamina, ordnance, and other equipment would all be unacceptably reduced. Therefore, with regret, the USArmy cannot allow the use of Dragonskin for military personnel. However we concede that it *may* be of use to noncombatants, for example news reporters."

    USArmy public relations are a brain-dead bunch of morons for not being more up-front about it. They had a golden opportunity to appear both professional and caring, and somehow ended up looking irrevocably like a bunch of corrupt, disingenous wankers. It's a classic example of the type of autistic military "communications" that have made the USA so reviled in the Middle East & elsewhere.

    Much respect to soldiers on the groud - the US jarhead, the UK marine with sore buttock, whoever. But USArmy high command should f*ck off, re-read their copies of Sun Tzu, and notice the bits that stress the importance of diplomacy in war.


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