The efficient synthesis of polyvinyl chloride PVC from vinyl chloride monomer VCM requires specific conditions and reagents to achieve high yield and desired properties of the resulting polymer. The process typically involves the polymerization of VCM using a free radical initiator under controlled temperature and pressure conditions. Here are the key parameters and their effects on the yield and properties of PVC:1. Initiator: The most common initiators used for PVC synthesis are organic peroxides, such as benzoyl peroxide, or azo compounds, like azobisisobutyronitrile AIBN . The initiator's role is to generate free radicals that initiate the polymerization reaction. The choice and concentration of the initiator can affect the reaction rate, molecular weight, and molecular weight distribution of the resulting PVC.2. Temperature: The polymerization reaction is typically carried out at temperatures between 40-60C. Higher temperatures can increase the reaction rate and lead to shorter polymer chains, while lower temperatures can result in longer polymer chains. The temperature also affects the initiator's decomposition rate, which influences the overall reaction rate and polymer properties.3. Pressure: The polymerization of VCM is usually performed under moderate pressure e.g., 10-20 atm to maintain the monomer in the liquid phase and ensure a high concentration of VCM in the reaction mixture. Higher pressures can lead to increased reaction rates and higher molecular weight PVC, while lower pressures may result in lower molecular weight PVC.4. Reaction time: The reaction time can affect the conversion of VCM to PVC and the molecular weight of the resulting polymer. Longer reaction times can lead to higher conversion and molecular weight, while shorter reaction times may result in lower conversion and molecular weight.5. Solvent: The use of a solvent, such as water or an organic solvent, can help control the polymerization reaction rate and the particle size of the resulting PVC. The choice of solvent can also affect the PVC's molecular weight and molecular weight distribution.6. Chain transfer agents: Chain transfer agents, such as thiols or mercaptans, can be used to control the molecular weight and molecular weight distribution of PVC. These agents can react with the growing polymer chain, effectively terminating the chain and initiating a new one. The concentration and type of chain transfer agent can significantly influence the PVC's properties.7. Polymerization method: There are several polymerization methods used for PVC synthesis, including suspension, emulsion, and bulk polymerization. Each method has its advantages and disadvantages, affecting the reaction rate, particle size, and properties of the resulting PVC.In summary, the efficient synthesis of PVC from VCM requires careful control of reaction conditions and the use of appropriate reagents. The choice of initiator, temperature, pressure, reaction time, solvent, chain transfer agents, and polymerization method can all significantly affect the yield and properties of the resulting polymer. By optimizing these parameters, it is possible to produce PVC with the desired characteristics for various applications.