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Blast-Proof Fabric Resists Multiple Explosions
An anonymous reader tips a Gizmodo story on a fabric whose properties are counterintuitive, to say the least of it. "Zetix is a fabric so strong it will resist multiple car bomb blasts without breaking. It absorbs and disperses the energy from explosions... it can be used in body armor, window covering, military tents, and hurricane defenses... [and] it can be used as medical sutures that won't damage body tissue. All of this is thanks to a property that apparently defies the laws of physics: helical-auxetics, objects that actually get fatter the more you stretch them. The concept makes my head want to explode, but when you see it in action it actually makes sense."
I'd be thrilled to have a motorcycle jacket and armour made better by this stuff.
Good news for pirates, then!
More seriously, I think it will work for bullets, since bullets burst fabrics by stretching them to the point of failure (and bullet-proof fabrics like Kevlar work by having a high tensile strength). The only question becomes how far does the bullet have to stretch the fabric until the strength rises enough to stop it? More than a couple of inches, and the bullet is into your internal organs anyway, so you have to reduce the looseness and flexibility of the fabric to prevent that from happening. The most obvious way to do that is the same way you do it for conventional bullet-proof vests: by adding hard plates or other rigid materials into the vest. The difference here is you might be able to use light materials that are themselves not bullet-proof (eg. wood, foam). The bullet could puncture these materials easily, but in dragging the material into the resulting bullet hole, the stretch factor would rise very rapidly and the fabric would suddenly become very strong.
OK, now imagine it stretched over titanium-frame or carbon-nanotube-frame body armor. The trick is to create some tension on the material and some distance between it and the body. You need a frame that can take the stresses of the material and the impacts, and combine that with the stopping power of the material.
Personally though, I'd rather see something like this used in car parts (bumpers, convertible roofs, tires, etc).