Figure 7 Mass distribution of polybutadiene considering four
catalytic sites.
Comparing Figure 7 with the others, it is observed that the distribution
of molar masses is significantly wider than the others, that is, the
polydispersity index presented by the simulation with four active sites
is the highest among the simulations and the closest to found in the
literature (MÉNDEZ-HERNÁNDEZ, 2016; VASCONCELOS, 2019). The distribution
still presents bimodality and the average molar masses are even greater
following the trend that the more active centers, the greater the
average molar masses.
It can be seen that all curves have a Gaussian model. The curves that
correspond to each site individually show unimodality. As a further
catalytic site is increased, bimodality is inserted in the polymer
distribution curve. It can be seen that in case 1, we have only one
unimodal Gaussian curve, whereas for all other cases this bimodality is
generated.
All the average molar masses and polydispersity index for all the four
simulations are presented in Table 5.
Table 5 Results of \(\mathbf{M}_{\mathbf{n}}\),\(\mathbf{M}_{\mathbf{w}}\) and PDI generated in all
cases.