Ultra-high-molecular-weight polyethylene (UHMWPE) :
The high molecular weight makes it a very tough material, but results in less efficient packing of the chains into the crystal structure as evidenced by densities of less than high density polyethylene .
UHMWPE can be made with any catalyst technology, although Ziegler catalysts are most common. Cause its outstanding toughness and its cut, wear and excellent chemical resistance, UHMWPE is used in a varied range of applications.
These include can and bottle handling machine parts, moving parts on weaving machines, bearings, gears, artificial joints, edge protection on ice rinks and butchers' chopping boards.
It competes with aramid in bulletproof vests, under the tradenames Spectra and Dyneema, and is commonly used for the construction of articular portions of implants used for hip and knee replacements.