Kinetic Modeling of Nitroxide-Mediated Polymerization: Conditions for Living and Controlled Polymerization

Simulations of conversion versus time, molecular weight ((M) over bar (n)), polydispersity index (PDI), and living fractions versus conversion plots are performed using the PREDICI software, to study the influence of several kinetic parameters on the living and controlled character of nitroxidemediated polymerization (NMP). In particular, the crucial role of the main equilibrium represented by both k(d) and k(c) (the rate coefficients respectively of dissociation and recombination) is highlighted. On the other hand, the importance of the initiation step, the targeted (M) over bar (n) value, and the initial excess of free nitroxide are also demonstrated. It is further proved that side reactions, such as disproportionation and transfer to solvent, have a strong impact on the polymerization characteristics.