PEX is a modified form of polythylene. The cross linking of polymers within polyethylene strengthens the material. Due to the cross linking, it can now withstand a wide variatin of temperatures from freezing point till about 200 degree fahrenheit. It is also reinforced to withstand chemical corrosion and is flexible in nature.
Depending on your area of application, there are basically 3 types of PEX pipes to choose from. There are 3 types of PEX pipes. They include PEX-A, PEX-B, and PEX-C . Although all the PEX pipes are made through different processes, the structure of their composition is similar. PEX pipes are made through cross-linking polyethylene molecules to one another so as to achieve a resultant strong substance.