Polyethylene is a thermoplastic polymer with a variable crystalline structure and a vast range of applications depending on the particular type. It is one of the most widely produced plastics in the world, with tens of millions of tons produced worldwide each year.
Polyethylene, like other plastics, starts with the distillation of hydrocarbon fuels (ethane in this case) into lighter groups called “fractions,” some of which are combined with other catalysts to produce plastics (typically via polymerization or polycondensation).
There are several types of polyethylene, and each one is best suited for a different set of applications.
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 highly 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.