How is PEX made?
The process starts with medium to high density polyethylene (MDPE or HDPE) resin. In some of the cross-linking methods, chemicals are added to the base resin which, either during extrusion or in a post-extrusion process, create the molecular cross-links through chemical reaction. These chemical methods can be compared to the vulcanization of rubber. Another method, radiation (nuclear or electron beam), uses high energy irradiation of the extruded pipe to form the molecular links. Finished properties of cross-linked material from these commercial methods are very similar.
