The synthesis of polyvinyl alcohol PVA from vinyl acetate monomer VAM involves two main steps: the polymerization of VAM to polyvinyl acetate PVAc and the hydrolysis of PVAc to PVA.1. Polymerization of VAM to PVAc:The optimal conditions for the polymerization of VAM to PVAc include a temperature range of 60-80C and the use of a free-radical initiator, such as benzoyl peroxide or azobisisobutyronitrile AIBN . The reaction is usually carried out in a solvent, like methanol or water, under an inert atmosphere e.g., nitrogen to prevent unwanted side reactions.2. Hydrolysis of PVAc to PVA:The hydrolysis of PVAc to PVA is typically carried out using an alkaline catalyst, such as sodium hydroxide NaOH or potassium hydroxide KOH . The reaction is performed in an aqueous solution at a temperature range of 60-90C. The degree of hydrolysis can be controlled by adjusting the reaction time and the concentration of the alkaline catalyst.The molecular weight of the resulting PVA polymer can be influenced by various reaction conditions:a Monomer concentration: A higher monomer concentration generally leads to a higher molecular weight polymer.b Initiator concentration: A lower initiator concentration results in a higher molecular weight polymer, as there are fewer initiating sites for the polymerization reaction.c Reaction temperature: Higher reaction temperatures can lead to a higher molecular weight polymer, as the rate of termination reactions decreases with increasing temperature.d Degree of hydrolysis: The molecular weight of PVA can be affected by the degree of hydrolysis of PVAc. A higher degree of hydrolysis results in a more complete conversion of PVAc to PVA, leading to a higher molecular weight polymer.By carefully controlling these reaction conditions, it is possible to tailor the molecular weight of the resulting PVA polymer to suit specific applications.