| Industrialist's Name | Scientist's View |
|---|---|
| Low Density Polyethylene (LDPE) (1939) | contains short and long branches, but all arising from one monomer (ethylene) |
| High Density Polyethylene (HDPE) (1958) | Ethylene homopolymer without branching. This is what scientists mean by linear polyethylene. |
| Medium Density Polyethylene (MDPE) (1959) | Ethylene polymer with a limited amount of comonomer. |
| Linear-Low Density Polyethylene (LLDPE) (1980) | Ethylene polymer made by a process allowing a greater amount of comonomer. The industrialist's term linear signifies an absence of long chain branching. |
| The present revolution in polyethylene is the development of metallocene catalysts to allow greater uniformity of molecular weight and branch distribution among molecules. These so-called single-site materials have recently started to be commercially available. | |