PARTLY ALCOHOLIZED POLYVINYL ACETATE) POLYMERS - PROPERTIES OF POLYMERS HYDROLYZED BY DIFFERENT ROUTES

Several polymers have been prepared over the entire compositional range of poly(vinyl acetate-alcohol) intramolecular mixtures by each of three routes - saponification with alkali, base-catalysed transesterification with methanolic methoxide, and acid-catalysed equilibration with acetic acid and hydrochloric acid mixtures. The polymers prepared by the three routes showed contrasting behaviour in their reaction with iodine in the presence of iodide and in their melting. The results are interpreted in terms of a linear block structure of acetate groups being required for high efficiency in iodine-complex formation and an attendant linear block structure of alcohol groups being required for high crystallinity and high melting-point. The order of degree of block structure in the polymeric products by the three routes is as follows - saponification, high; transesterification, intermediate; acid-equilibrium, hardly any. The use of the iodine complex for the analytical determination of samples from this system is discussed. © 1979.