A statistical approach is developed, based on a Monte Carlo method, in order to determine the statistical composition of a polyamide-6 sample composed of caprolactam (an AB-type monomer) and of a di-acid (A2 type) or a tri-acid (A3 type) as coupling agents. For this composition, the linear rheological behavior of these systems is predicted using a tube-based theory. This allows us to show that while coupling agents of type A2 can be seen as flow improver, the effect of branching agents of type A3 , depending on the synthesis recipe and the conversion level, can lead either to an increase or to a decrease of the viscosity. By adding specific amount of these agents, we also show that it is possible to obtain materials with the same zero-shear viscosity but with different shear thinning behavior. Furthermore, the polydispersity of linear samples of the same average number molecular weight, M n , is discussed in function of the amount of A2 monomers they contain. Ranging from 2 to 1.5, this difference in polydispersity is expected to have a significant influence on the processing behavior of such materials.
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