UHMW stands for ultra high molecular weight polyethylene. Polyethylene materials are semi-crystalline materials with excellent chemical resistance, good fatigue and wear resistance, and a wide range of properties (due to differences in length of the polymer chain). Polyethylene materials are easy to distinguish from other plastics because they float in water. They provide good resistance to organic solvents, degreasing agents, and electrolytic attack. They have a higher impact strength, but lower working temperatures and tensile strengths than polypropylene. They are also light in weight, resistant to staining, and have low moisture absorption rates.