Polyethylene is commonly categorized into one of several major compounds, the most common of which include LDPE, LLDPE, HDPE, and Ultrahigh Molecular Weight Polypropylene. Other variants include Medium Density Polyethylene (MDPE), Ultra-low-molecular-weight polyethylene (ULMWPE or PE-WAX), High-molecular-weight polyethylene (HMWPE), High-density cross-linked polyethylene (HDXLPE), Cross-linked polyethylene (PEX or XLPE), Very-low-density polyethylene (VLDPE), and Chlorinated polyethylene (CPE).

Low-Density Polyethylene (LDPE) is a very flexible material with unique flow properties that makes it particularly suitable for shopping bags and other plastic film applications. LDPE has high ductility but low tensile strength, which is evident in the real world by its propensity to stretch when strained.

Linear Low-Density Polyethylene (LLDPE) is very similar to LDPE, but offers added advantages. Specifically, the properties of LLDPE can be altered by adjusting the formula constituents, and the overall production process for LLDPE is typically less energy-intensive than LDPE.

High-Density Polyethylene (HDPE) is a robust, moderately stiff plastic with a highlypolyethylene-hdpe-trashcan-1 crystalline structure. It is frequently used in plastic for milk cartons, laundry detergent, garbage bins, and cutting boards.

Ultrahigh Molecular Weight Polyethylene (UHMW) is an extremely dense version of polyethylene, with molecular weights typically an order of magnitude greater than HDPE. It can be spun into threads with tensile strengths many times greater than steel and is frequently incorporated into bulletproof vests and other high-performance equipment.