Reactivity pattern scheme monomer parameters

The patterns of reactivity scheme is a more advanced treatment of copolymerization behavior. It follows the general form of the Q-e scheme but does not assume that the same intrinsic reactivity or polarity factors apply both to a monomer and its corresponding radical [Bamford and Jenkins, 1965 Jenkins, 1999, 2000 Jenkins and Jenkins, 1999]. The monomer reactivity ratio for monomer 1 is expressed in terms of four parameters... 

Table 6-8 shows values of the various parameters needed to calculate monomer reactivity ratios from Eqs. 6-60 and 6-62 [Jenkins and Jenkins, 1999]. The monomers in Table 6-8 are lined up in order of their u values. The Patterns of Reactivity scheme, like the Q e. scheme, is an empirical scheme. Monomer reactivity ratios calculated by the patterns of reactivity scheme are generally closer to experimental values than those calculated by the Q e scheme, which supports the rationale of assigning different polarity values to a monomer and the radical derived from the monomer. 

The relation between monomer reactivity ratios and the Alfrey-Price Q-e parameters is explained in the introduction to the tables of monomer reactivity ratios and Q-e values, compiled by Robert Z. Greenley and published in the present volume (1,2). Although very widely used, the Q-e scheme is well known to have serious limitations (3), which have prompted several attempts to improve upon it. Qne such endeavour was the Patterns of Reactivity scheme, first described as long ago as 1959 (4-7), when the Q-e scheme was only about ten years old despite the indisputably more satisfaetory basis of this procedure, it did not achieve popularity but recent revisions have greatly improved both its accessibility and its accuracy (3,8,9). 

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