281055 Free Radical Copolymerization of Acrylic Monomers Using Kinetic Monte Carlo Simulations

Monday, October 29, 2012: 4:05 PM
Butler West (Westin )
Venkat Reddy Regatte, Chemical and Biological Engineering, Northwestern University, Evanston, IL, Steven G. Arturo, The Dow Chemical Company, Freeport, TX and Linda J. Broadbelt, Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL

The monomer sequence in the backbone of polymer chains has a dramatic impact on polymer properties. It is important to tune the explicit sequence information of the polymer chains for well-defined structures of the copolymers for a wide range of applications. Stochastic simulations are an attractive and flexible alternative to deterministic methods in modeling the chemical and physical systems at the molecular scale. One of the advantages of stochastic simulation methods for kinetic modeling, i.e., kinetic Monte Carlo, is its ability to track the sequence of the monomers in polymer chains as well as molecular weight distribution, monomer composition and polydispersity, which have a large impact on the properties of the polymers in end-use applications.

The aim of this work is to study the detailed chemistry of copolymerization of acrylic monomers using kinetic Monte Carlo (KMC) simulations to probe the properties of the polymers such as molecular weight distribution, polymer composition, explicit sequence distribution and conversion. The simulation framework, developed in an object-oriented platform, is applied for free radical polymerization of acrylic monomers. The framework is developed for any given number of monomers and all possible reaction types relevant to the synthesis of the copolymers. Classic free radical polymerization steps like initiator decomposition, initiation, propagation, termination via recombination and disproportionation, and chain transfer were incorporated in the model. Since the penultimate unit of a polymer radical may have a significant effect on reactivity of the growing polymer chains, and thus, the propagation rate coefficients, the model framework also has provisions to consider both propagation and de-propagation with penultimate effects taken into account.

Finally, a comparison of the KMC simulation results with experimental data will be discussed. Specifically, the effect of initiator concentration, monomer composition and the monomer concentration on the final properties of the copolymer will be explored.

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