An improved method of calculating copolymerization reactivity ratios

Abstract

Abstract A nonlinear least‐squares method for solving for r 1 and r 2 the copolymerization reactivity ratios, is explained. This new method is superior to all other methods that have been used heretofore in the following ways: ( 1 ) a unique pair of values is obtained which does not depend on the judgment of the person examining the data; ( 2 ) this pair of values can be shown mathematically to be the best pair obtainable from the data at hand; ( 3 ) the errors are quantitatively defined in meaningful terms: and ( 4 ) the data are checked to see how well they fit the copolymer equation. A basis for selecting experimental conditions which will provide data from which precise values of the reactivity ratios can be obtained is explained, and experimental conditions appropriate for obtaining these precise values over a wide range of r 1 , r 2 values are presented in tabular form.