IUPAC recommended experimental methods and data evaluation procedures for the determination of radical copolymerization reactivity ratios from composition data

Abstract

The IUPAC working group on “Experimental Methods and Data Evaluation Procedures for the Determination of Radical Copolymerization Reactivity Ratios” recommends a robust method to determine reactivity ratios from copolymer composition data using the terminal model for copolymerization. The method is based on measuring conversion (X) and copolymer composition (F) of three or more copolymerization reactions at different initial monomer compositions (f₀). Both low and high conversion experiments can be combined, or alternatively only low conversion experiments can be used. The method provides parameter estimates, but can also reveal deviations from the terminal model and the presence of systematic errors in the measurements. Special attention is given to error estimation in F and construction of the joint confidence interval for reactivity ratios. Previous experiments measuring f₀ − F or f − X can also be analyzed with the IUPAC recommended method. The influence of systematic errors in the measurements on the reactivity ratio determinations is investigated, including ways to identify and mitigate such errors.