Chain statistics in vinyl acetate-vinyl alcohol multiblock copolymers

The kinetics and structure of products of the alkaline hydrolysis of poly(vinyl acetate) in an acetone-water mixture are studied via 1H NMR spectroscopy. The reaction is considerably accelerated and, according to the dynamic light-scattering data, is accompanied by polymer-coil expansion. The model of the effect of neighboring units is shown to be inapplicable to description of the general kinetics of the process; however, it may be successfully used for the quantitative interpretation of the experimental dependences of the triad composition of macromolecules on conversion. Thus, the conformational factors affect the reactivity of vinyl acetate groups, regardless of the nature of their nearest chain neighbors. This circumstance makes it possible to use the neighbor-effect model to describe the unit distribution over chains of the reaction product, vinyl acetate-vinyl alcohol copolymer, and thus to obtain information necessary for studying the relationship between the chain structure and properties of statistical multiblock copolymers.