What is PE?

Polyethylene is a thermoplastic polymer with variable crystalline structure and an extremely large range of applications depending on the particular type. It is one of the most widely produced plastics in the world (tens of millions of tons are produced worldwide each year). The commercial process (the Ziegler-Natta catalysts) that made PE such a success was developed in the 1950s by German and Italian scientists Karl Ziegler and Giulio Natta.
There are a vast array of applications for polyethylene in which certain types are more or less well suited. Generally speaking, High Density Polyethylene (HDPE) is much more crystalline, has a much higher density, and is often used in completely different circumstances than Low Density Polyethylene (LDPE). For example, LDPE is widely used in plastic packaging such as for grocery bags or plastic wrap. HDPE by contrast has common applications in construction (for example in its use as a drain pipe). Ultrahigh Molecular Weight Polyethylene (UHMW) has high performance applications in things such as medical devices and bulletproof vests.

What are the Characteristics of PE?

Polyethylene (PE) is classified as a “thermoplastic”, the name has to do with the way the plastic responds to heat. Thermoplastic materials become liquid at their melting point (110-130 degrees Celsius in the case of LDPE and HDPE respectively). A major useful attribute about thermoplastics is that they can be heated to their melting point, cooled, and reheated again without significant degradation. Instead of burning, thermoplastics like Polyethylene liquefy, which allows them to be easily [injection molded] and then subsequently recycled.
HDPE, LDPE, LLDPE are Different Types of Polyethylene.