The mechanism of polymerization in the synthesis of polyethylene involves the addition of ethylene monomers to form a long chain polymer. There are two primary methods for synthesizing polyethylene: free radical polymerization and coordination polymerization also known as Ziegler-Natta polymerization .1. Free Radical Polymerization: In this method, a free radical initiator such as a peroxide is used to initiate the polymerization process. The initiator generates a free radical, which reacts with an ethylene monomer to form a new radical. This new radical reacts with another ethylene monomer, and the process continues, forming a long chain of polyethylene. The reaction is highly exothermic and typically occurs at high temperatures and pressures.2. Coordination Polymerization Ziegler-Natta Polymerization : This method involves the use of a transition metal catalyst, typically a titanium-based compound, and an aluminum-based co-catalyst. The catalyst coordinates with the ethylene monomer, allowing for the insertion of the monomer into the metal-carbon bond. This process continues, adding more monomers to the chain until the polymer reaches the desired length. This method allows for greater control over the polymer's properties and typically produces a more linear and crystalline polyethylene.Controlling reaction parameters such as temperature and catalyst concentration can significantly affect the properties of the polymer produced. Some of these effects include:1. Molecular Weight: Higher temperatures and lower catalyst concentrations generally result in lower molecular weight polymers. Lower molecular weight polymers have lower tensile strength, lower melting points, and are more easily processed.2. Polymer Structure: The choice of catalyst and reaction conditions can influence the structure of the polymer, such as its linearity and degree of branching. Linear polymers have higher crystallinity, which results in higher melting points, greater tensile strength, and increased density. Branched polymers, on the other hand, have lower crystallinity, lower melting points, and lower density.3. Polymerization Rate: Higher temperatures and higher catalyst concentrations can increase the rate of polymerization. However, this can also lead to a broader distribution of molecular weights, which can affect the polymer's properties.4. Catalyst Residue: The concentration of catalyst used in the reaction can affect the amount of catalyst residue present in the final polymer. High levels of catalyst residue can negatively impact the polymer's properties, such as its color, clarity, and mechanical properties.In summary, the mechanism of polymerization in the synthesis of polyethylene involves the addition of ethylene monomers to form a long chain polymer. Controlling reaction parameters such as temperature and catalyst concentration can significantly affect the properties of the polymer produced, including molecular weight, polymer structure, polymerization rate, and catalyst residue.