高化双语课件共聚合5 6 q,e scheme.ppt

Part 6 the activity of monomer and Q,e scheme 1. The experimental methods for checking the activity of monomers and radicals； 2. The influence of structural factors,such as resonance effects and steric effects, on the activity of monomers and radicals； 3. Q,e scheme is the bridge between the activity of monomers and radicals and can be estimated the reactivity ratio of monomer pairs. we can not distinguish the activity of monomers and radicals in the homopolymerization. Why ? 1) Kp of propagation is not only depends on M, but also M *; 2) there are lack of the frame of reference. 5.6.1 the relative activity of monomers Reciprocal of reactivity ratio（1／r1）= k12／k11， It stand for the ratio of the propagation constant of a radical with another monomer to that with its mother monomer， We can use 1/r1 to compare the relative activity with a series of M2 The copolymerization of～～M1*with different second monomer ： The data in the table show the activity of the monomers towards the same radical The activity of monomers in the table decrease from the top to the end： e.g. ～～VAc* For the conjugation system with the radicals S* and B*, the activity of some monomers is deregulation. Conclusion： The activity of monomers with different substitute groups are in the following order： CH2=CHX: C6H5-, CH2=CH- > -CN, -COR > -COOH, -COOR > -Cl > -OCOR, -R > -OR, -H The relative activity of CH2=CHX shows the influence of X on the activity of monomers： a)the monomers with conjugation substitute group, such as B, S, have the biggest activity. b)the monomers with strong electron-attracted substitute group, such as AN, MMA, also have good activity. c) the monomers with electron-repulsion substitute group, such as VAc、CH2=CHOR, has smallest activity. 5.6.2 the relative activity of radicals from r1 = k11／k12 and the available kP、r1, we can calculate k12 = k11/r1 = (kP/r1)（see table 5-7） the data of rows in table 5-7show the relative activity of series of radicals to