Pseudo-Homopolymerization Approach To Predict the Molecular Weight Distribution in the Copolymerization via Activator Regenerated by Electron Transfer Atom Transfer Radical Polymerization

Abstract

An efficient kinetic model based on the pseudo-homopolymerization (PHP) and reduced stiffness by quasi-steady state approximation (RQSSA) methodology is presented to compute the molecular weight distribution (MWD) in the activator regenerated by electron transfer via atom transfer radical copolymerization. The copolymerization of butyl methacrylate and butyl acrylate is taken as basis of the study; validation with the experimental data results in good agreement, and a deviation between the prediction of the Mayo−Lewis equation and the model estimation is presented. The MWD is dependent on the fed monomer composition. A semibatch process with an extra addition of reduced agent resulted in an increased polymerization rate; however, this affects the process control, and a broader MWD is obtained. The computational time expended to compute the MWD is on the order of seconds or minutes, which can be reduced by using a new expression to calculate the bounds of the MWD.

The method of moments used in polymerization reaction engineering for 70 years: An overview, tutorial, and minilibrary

“…For the benefit of the reader, we show the procedure for the derivation of the second moment for the dead species in the termination by combination term, given by Equation (23):…”

“…The result is a prediction of the MWD that can be directly comparable to that obtained by GPC data (after a proper re-scaling), as in Figure 5. This methodology is named reduced stiffness byquasi-steady state approximation (RSQSSA) and has been applied to FRPs [83] of linear and nonlinear polymerizations, RAFT, [18,19,56] ATRP, [13] NMP, [56] copolymerizations, [23] and catalytic coordination polymerization (CCP). [56] However, the strict application of this technique requires the testing of the validity of the QSSA to, for example, the living polymer population.…”

“…However, the challenge is more complex when one faces polymerizations producing chains with high molecular weights, (e.g. high-density polyethylene [HDP]), [8] high density of branching (lowdensity polyethylene [LDPE]), [14,15] crosslinking, [16] terminal double bond propagation, [17] two-dimensional [18][19][20][21] or multi-dimensional species, [22] copolymerizations, [23] multicomponent polymerizations, [24] and heterogeneous phase processes. In the latter cases, the dimension of the ODE system may become huge; additionally, the systems may present numerical stiffness, and therefore their solution through straightforward integration techniques, such as implicit integration methods, is highly demanding for an ordinary computer and requires very long running time, high-performance computers, or exceptional programming.…”