Significance of Reactivity Ratios

T0 gain an appreciation for the physical significance of (12.11), let s look at some special cases of the reactivity ratios. 

Case 1 = r2 = 0. With both reactivity ratios zero, neither type of chain 

so the polymer formed will be a physical mixture of homopolymer 1 and homopolymer 2 chains. 

Case 3 r = 2 = 1. Under these conditions, the growing chains find the monomers equally attractive, so the addition depends only on the ratio of monomers in the vicinity of the chain ends, Fi =A- 

Case 4 r r — 1. This is the so-called ideal copolymerization, where each chain displays the same preference for one of the monomers over the other tcxxlki2 = k2i/k22, so it doesn t matter what s on the end of the chaixu In this case, (12.11) reduces to 

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