The effects of various processing parameters on the molecular weight and degree of hydrolysis of polyvinylalcohol (PVA)

Polyvinylalcohol (PVA) is a water soluble polymer with extensive use in fibres, paints, adhesives and emulsifiers production. The main industrial raw material for theproduction of PVA is polyvinylacetate (PVAc). PVA is produced by hydrolysis of PVAc in alcoholic solvents such as methanol and ethanol in the presence of base or acid catalysts. Due low hydrolysis reaction rate in the presence of acid catalysts, usually base catalysts such as potassium and sodiumhydroxide is used in the practice. The basic properties of PVA such as solubility, surface tension, viscosity etc largelydepends on the degree of hydrolysis and molecular weight. Commercial PVA may be fully hydrolyzed (97.5-99.5%) or partially hydrolyzed (hy-89%). The molecular weight ofcommercial PVA may be low (500), intermediate (1700) or high (2000). To obtain a PVA with certain degree of hydrolysis and molecular weight the processing parameters such as temperature, time, type and amount of catalyst, and solvent should be controlled. In this research we investigatethe effects of temperature and time on molecular weight and degree of hydrolysis