The synthesis of high molecular weight polyvinyl alcohol PVA from vinyl acetate monomer VAM typically 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:Optimum reaction conditions for the polymerization of VAM to PVAc include:- Temperature: 60-80C- Pressure: Atmospheric pressure 1 atm is generally sufficient, as the reaction is not highly pressure-sensitive.- Catalyst: Free-radical initiators like azobisisobutyronitrile AIBN or benzoyl peroxide are commonly used. The catalyst concentration typically ranges from 0.1 to 1.0 wt% based on the VAM monomer.2. Hydrolysis of PVAc to PVA:Optimum reaction conditions for the hydrolysis of PVAc to PVA include:- Temperature: 60-90C- Pressure: Atmospheric pressure 1 atm is generally sufficient, as the reaction is not highly pressure-sensitive.- Catalyst: A strong base like sodium hydroxide NaOH or potassium hydroxide KOH is used for the hydrolysis. The catalyst concentration depends on the desired degree of hydrolysis, but typically ranges from 0.5 to 2.0 equivalents of the base per acetate group in PVAc.To achieve high molecular weight PVA, it is essential to control the reaction conditions, particularly the temperature and catalyst concentration, to minimize chain termination and transfer reactions during the polymerization step. Additionally, the degree of hydrolysis should be optimized to ensure the desired properties of the final PVA product.