Polyethylene plastic is characterized by toughness, near-zero moisture absorption, excellent chemical resistance, excellent electrical chemical resistance, excellent electrical insulating properties, low coefficient of friction, and ease of processing. Polyethylene plastics are classified by density and the primary differences are in rigidity, heat resistance, chemical resistance, and ability to sustain loads. In general, as density increases, harness, heat resistance, stiffness, and resistance to permeability increase. Low-density polyethylene plastics are quite flexible, with high impact strength and relatively low heat resistance.