Analysis of the linear methods for determining copolymerization reactivity ratios. VI. A comprehensive critical reexamination of oxonium ion copolymerizations

The reactivity ratios of 180 published oxonium copolymerization systems have been reviewed in terms of the extended Kelen–Tüdos method. Only 32 (17.8%) systems were described in sufficient detail for reevaluation and classification. r Values, together with their 95% confidence limits have been calculated. A quantity δ□, suitable for classification of the systems, has been introduced. Of the 32 reevaluated systems, five were found to belong to class I and 14 to class I(!), i.e., 19 systems for which the conventional copolymerization equation was found to be adequate. Class II systems were not found. Finally, 13 systems were judged to belong in class III, i.e., systems for which the experimental data are inconsistent and the published r values meaningless.