by Lattuada M, Del Gado E, Abete T, de Arcangelis L, Lazzari S, Diederich V, Storti G, Morbidelli M
Abstract:
Modeling free radical polymerization processes in the presence of cross-linkers is a challenging problem that has been addressed using numerous techniques for over more than half a century. However, a model providing a comprehensive description of the phenomenon has not been proposed yet. In this work, we implement a simple free-radical polymerization scheme of a monovinyl (difunctional) monomer and a divinyl (tetrafunctional) cross-linker in a Monte Carlo (MC) scheme, which describes polymer dynamics using a bond-fluctuation model. MC simulations allow us to follow the entire polymerization kinetics and the formation of a percolating network (gel phase) by realistically taking into account diffusion limitations, to extract scaling information at the percolation threshold and to recover the distribution of number of monomer units between two successive fully cross-linked units, from which the extent of swelling can be computed. The predictions of MC simulations are also successfully compared to a kinetic model based on numerical fractionation, with kinetic constants used as fitting parameters. MC data and kinetic simulations are compared to some experimental data on the swelling behavior of polyacrylamide hydrogels and of poly(methyl methacrylate) (PMMA) gels, exhibiting good agreement. We conclude that the proposed MC simulation scheme represents a powerful tool from which precious and experimentally inaccessible information on polymerization processes in the presence of cross-linkers can be extracted.
Reference:
Kinetics of Free-Radical Cross-Linking Polymerization: Comparative Experimental and Numerical Study (Lattuada M, Del Gado E, Abete T, de Arcangelis L, Lazzari S, Diederich V, Storti G, Morbidelli M), In MACROMOLECULES, volume 46, 2013. (Articolo in rivista)
Bibtex Entry:
@article{lat13,
author = {Lattuada M, and Del Gado E, and Abete T, and de Arcangelis L, and Lazzari S, and Diederich V, and Storti G, and Morbidelli M,},
pages = {5831-5841},
title = {Kinetics of Free-Radical Cross-Linking Polymerization: Comparative
Experimental and Numerical Study},
volume = {46},
note = {Articolo in rivista},
issn = {0024-9297},
journal = {MACROMOLECULES},
doi = {dx.doi.org/10.1021/ma4012347},
year = {2013},
wosId = {000323193300002},
scopusId = {2-s2.0-84881602888},
abstract = {Modeling free radical polymerization processes in the presence
of cross-linkers is a challenging problem that has been addressed using
numerous techniques for over more than half a century. However, a model
providing a comprehensive description of the phenomenon has not been
proposed yet. In this work, we implement a simple free-radical polymerization
scheme of a monovinyl (difunctional) monomer and a divinyl (tetrafunctional)
cross-linker in a Monte Carlo (MC) scheme, which describes polymer
dynamics using a bond-fluctuation model. MC simulations allow us to follow
the entire polymerization kinetics and the formation of a percolating network
(gel phase) by realistically taking into account diffusion limitations, to extract
scaling information at the percolation threshold and to recover the distribution
of number of monomer units between two successive fully cross-linked units, from which the extent of swelling can be computed.
The predictions of MC simulations are also successfully compared to a kinetic model based on numerical fractionation, with
kinetic constants used as fitting parameters. MC data and kinetic simulations are compared to some experimental data on the
swelling behavior of polyacrylamide hydrogels and of poly(methyl methacrylate) (PMMA) gels, exhibiting good agreement. We
conclude that the proposed MC simulation scheme represents a powerful tool from which precious and experimentally
inaccessible information on polymerization processes in the presence of cross-linkers can be extracted.}
}