Characteristics of Dyneema
Dyneema fibers were invented over 20 years ago and by a company called DSM Dyneema and has been in production since 1990. Dyneema fiber is a gel-spun, multi-filament fiber that is created from ultra high molecular weight polyethylene. Polyethylene is a common chemical combination used in many plastics, but Dyneema's is much more than a common plastic. What does this mean to everyone without a chemical engineering degree? It means that the fiber has extreme strength, minimal weight and a large amount of useful applications.
Dyneema's chemical composition allows it to boast of many characteristics such as:
- Resistance to most chemicals
- Low density
- Invisible to ultra-violet light sources and thermal imaging devices
- Floats on water
- Smooth to the touch
- Fire resistant and self-extinguishing
- Can withstand extreme cold and hot temperatures
- Biologically inert (doesn't cause a reaction to the human body)
- Sonic velocity and acoustic impedance near that of water
- High electrical resistance
- Elongation at break is low, energy needed to break is high
- Very high strength
On a weight-for-weight basis, Dyneema is 15 times stronger than steel and is 40 percent stronger than aramid fibers [source: Dyneema]. Aramid fibers are another type of synthetic material that has similar characteristics, although not all; one of the most common types of aramid fiber is Kevlar.
Dyneema can be created as a continuous filament yarn, used for things like strong ropes or nets, or as a unidirectional sheet. The unidirectional sheet is created in layers with one layer placed on top of another at a 90-degree angle to the layer beneath it [source: SoldierMod.com]. This layering allows the fiber to absorb harsh impacts and disperse energy quickly and efficiently to other layers.
On the next page, we'll find out how Dyneema is used to armor vehicles and how it protects occupants during an explosion.