The synthesis of polyethylene from ethylene monomer typically occurs through a process called polymerization. There are two main types of polymerization used to produce polyethylene: free radical polymerization and coordination polymerization also known as Ziegler-Natta polymerization . Here, I'll describe the step-by-step chemical reaction mechanism for the free radical polymerization of ethylene.1. Initiation: The process begins with the formation of a free radical, which is a highly reactive species with an unpaired electron. This can be achieved by using a free radical initiator, such as a peroxide or an azo compound. The initiator undergoes homolytic cleavage, producing two free radicals.R-R 2R where R represents a free radical 2. Propagation: The free radical reacts with an ethylene monomer, breaking the double bond in the ethylene and forming a new free radical on the carbon atom.R + CH2=CH2 R-CH2-CH2The newly formed free radical reacts with another ethylene monomer, repeating the process and extending the polymer chain.R-CH2-CH2 + CH2=CH2 R-CH2-CH2-CH2-CH2This propagation step continues, with the free radical reacting with more ethylene monomers and growing the polymer chain.3. Termination: The polymerization reaction is terminated when two free radicals react with each other, forming a covalent bond and ending the growth of the polymer chain.R-CH2-CH2 + CH2-CH2-R R-CH2-CH2-CH2-CH2-RAlternatively, termination can occur through chain transfer, where the free radical reacts with another molecule such as an initiator or solvent , transferring the free radical to that molecule and ending the growth of the polymer chain.R-CH2-CH2 + X-Y R-CH2-CH2-X + Y where X-Y represents another molecule The final product is a high molecular weight polyethylene polymer, which can be further processed and used in various applications such as plastic films, containers, and pipes.