Determination of penultimate model reactivity ratios and their non-uniqueness

Nine copolymerization systems reported in literature have been analyzed for determining the terminal and penultimate model reactivity ratios and their non-uniqueness. A universal relationship covering the reactivity ratios and independent of monomer pair type has been developed and successfully verified for the copolymer systems.A new method for determining the reactivity ratios has been developed using monomer feed concentrations at two specific copolymer compositions and is found to give reliable and accurate values.