The synthesis of polyvinyl alcohol PVA from vinyl acetate monomer VAM is typically carried out through a two-step process: 1 polymerization of vinyl acetate to form polyvinyl acetate PVAc , and 2 hydrolysis of polyvinyl acetate to form polyvinyl alcohol.1. Polymerization of vinyl acetate:The ideal reaction conditions for the polymerization of vinyl acetate to form polyvinyl acetate are typically in the temperature range of 40-80C. The reaction is carried out in an aqueous solution, and the polymerization is initiated using a free-radical initiator, such as potassium persulfate or benzoyl peroxide. The reaction can be performed under an inert atmosphere, such as nitrogen, to prevent unwanted side reactions.Catalyst: The most common catalysts used for this reaction are free-radical initiators, as mentioned above.2. Hydrolysis of polyvinyl acetate:The hydrolysis of polyvinyl acetate to form polyvinyl alcohol is typically carried out in the presence of a base, such as sodium hydroxide NaOH or potassium hydroxide KOH , at elevated temperatures 60-100C . The reaction is performed in an aqueous solution, and the degree of hydrolysis can be controlled by adjusting the reaction time and the concentration of the base.Catalyst: The catalysts used for this reaction are strong bases, such as sodium hydroxide or potassium hydroxide.Molecular weight variation with reaction conditions:The molecular weight of the resulting polyvinyl alcohol can be influenced by several factors, including the reaction conditions during the polymerization of vinyl acetate and the hydrolysis of polyvinyl acetate.- During the polymerization of vinyl acetate, the concentration of the initiator and the reaction temperature can affect the molecular weight of the resulting polyvinyl acetate. Higher initiator concentrations and lower temperatures generally lead to lower molecular weights, while lower initiator concentrations and higher temperatures result in higher molecular weights.- During the hydrolysis of polyvinyl acetate, the degree of hydrolysis can affect the molecular weight of the resulting polyvinyl alcohol. A higher degree of hydrolysis can lead to a lower molecular weight due to chain scission during the hydrolysis process.In summary, the ideal reaction conditions for the synthesis of polyvinyl alcohol from vinyl acetate monomer involve the use of free-radical initiators for the polymerization of vinyl acetate and strong bases for the hydrolysis of polyvinyl acetate. The molecular weight of the resulting polymer can be influenced by various reaction conditions, such as initiator concentration, reaction temperature, and degree of hydrolysis.