Dependence of computed copolymer reactivity ratios on the calculation method. I. Effect of experimental setup

Five calculation methods for estimating reactivity ratios are compared. Two of these methods are only valid at low conversion, two methods are assumed to be valid up to high conversion, and the fifth method is the integrated form of the copolymer equation. Data were simulated for selected couples of r ‐values and two conversion levels. The data were randomly disturbed by normal error with mean zero. As (the) monomer feed ratio(s) will be drifting during the course of reaction, the influence of an approximated monomer feed ratio on the r ‐values calculated was also examined. When conversion is low, all methods give estimates with low precision. High conversion results in larger precision, however, for several methods bias appears. For calculation methods that need information about an approximated monomer feed ratio, the influence of this approximation appears to be rather important especially if the r ‐values are dissimilar or conversion is high.