Process :

Monomer :

The ingredient or monomer is ethylene , a gaseous hydrocarbon with the formula C2H4, which can be viewed as a pair of methylene groups (=CH2) connected to each other. cause the catalysts are highly reactive, the ethylene must be of high purity. Typical specifications are 5 ppm for water, oxygen, as well as other alkenes. Standard contaminants include N2, ethane, and methane. Ethylene is usually produced from petrochemical sources, but also is generated by dehydration of ethanol.

Polymerization :

Ethylene is a rather stable molecule that polymerizes only upon contact with catalysts. The conversion is extremely exothermic, that is the process releases a lot of heat. Coordination polymerization is the most pervasive technology, which means that metal chlorides or metal oxides are used. The most common catalysts consist of titanium (III) chloride, the so-called Ziegler-Natta catalysts. Another type of catalyst is the Phillips catalyst, prepared by depositing chromium (VI) oxide on silica. Ethylene can be produced through radical polymerization, but this route has only limited utility and typically needs high pressure apparatus.