Product Relation of Copolymerization Reactivity Ratios

The copolymerization reactivity ratios designated as r_i = k_ii/k_ij are characteristic of thermodynamic conditions, such as temperature, pressure, and concentration, in which the temperature dependence has been demonstrated by kinetic procedures [14]. It is noted that in radical copolymerization the simple product of the reactivity ratios, e.g., r₁, r₂ generally tends to move toward unity with increasing temperature [2] and that for ionic copolymerization it is usually close to unity [5]. Such an inclination, however, involves some ambiguity in evaluating all the reported data [6] concerning the polymerization conditions.