TY - JOUR
T1 - Advanced computational strategies for modelling the evolution of full molecular weight distributions formed during multiarmed (star) polymerisations
AU - Chaffey-Millar, Hugh
AU - Busch, Markus
AU - Davis, Thomas P.
AU - Stenzel, Martina H.
AU - Barner-Kowollik, Christopher
PY - 2005/3/31
Y1 - 2005/3/31
N2 - A novel computational strategy is described for the simulation of star polymerisations, allowing for the computation of full molecular weight distributions (MWDs). Whilst, the strategy is applicable to a broad range of techniques for the synthesis of star polymers, the focus of the current study is the simulation of MWDs arising from a reversible addition fragmentation chain transfer (RAFT), R-group approach star polymerisation. In this synthetic methodology, the arms of the star grow from a central, polyfunctional moiety, which is formed initially as the refragmenting R-group of a polyfunctional RAFT agent. This synthetic methodology produces polymers with complex MWDs and the current simulation strategy is able to account for the features of such complex MWDs. The strategy involves a kinetic model which describes the reactions of a single arm of a star, the kinetics of which are implemented and simulated using the PREDICI® program package. The MWDs resulting from this simulation of single arms are then processed with an algorithm we describe, to generate a full MWD of stars. The algorithm is applicable to stars with an arbitrary number of arms. The kinetic model and subsequent algorithmic processing techniques are described in detail. A simulation has been parameterised using rate coefficients and densities for a 2,2′-azoisobutyronitrile (AIBN) initiated, bulk polymerisation of styrene at 60°C. A number of kinetic parameters have been varied over large ranges. Conversion normalised simula tions were performed, leading to information regarding star arm length, polydispersity index (PDI) and the fraction of living arms. These screening processes provided a rigorous test for the kinetic model and also insight into the conditions, which lead to optimal star formation. Finally, full MWDs are simulated for several RAFT agent/initiator ratios as well as for stars with a varying number of arms.
AB - A novel computational strategy is described for the simulation of star polymerisations, allowing for the computation of full molecular weight distributions (MWDs). Whilst, the strategy is applicable to a broad range of techniques for the synthesis of star polymers, the focus of the current study is the simulation of MWDs arising from a reversible addition fragmentation chain transfer (RAFT), R-group approach star polymerisation. In this synthetic methodology, the arms of the star grow from a central, polyfunctional moiety, which is formed initially as the refragmenting R-group of a polyfunctional RAFT agent. This synthetic methodology produces polymers with complex MWDs and the current simulation strategy is able to account for the features of such complex MWDs. The strategy involves a kinetic model which describes the reactions of a single arm of a star, the kinetics of which are implemented and simulated using the PREDICI® program package. The MWDs resulting from this simulation of single arms are then processed with an algorithm we describe, to generate a full MWD of stars. The algorithm is applicable to stars with an arbitrary number of arms. The kinetic model and subsequent algorithmic processing techniques are described in detail. A simulation has been parameterised using rate coefficients and densities for a 2,2′-azoisobutyronitrile (AIBN) initiated, bulk polymerisation of styrene at 60°C. A number of kinetic parameters have been varied over large ranges. Conversion normalised simula tions were performed, leading to information regarding star arm length, polydispersity index (PDI) and the fraction of living arms. These screening processes provided a rigorous test for the kinetic model and also insight into the conditions, which lead to optimal star formation. Finally, full MWDs are simulated for several RAFT agent/initiator ratios as well as for stars with a varying number of arms.
KW - Kinetics (polym.)
KW - Modelling
KW - Reversible addition fragmentation chain transfer (RAFT)
KW - Simulations
KW - Star polymers
UR - http://www.scopus.com/inward/record.url?scp=20444473819&partnerID=8YFLogxK
U2 - 10.1002/mats.200400075
DO - 10.1002/mats.200400075
M3 - Article
AN - SCOPUS:20444473819
SN - 1022-1344
VL - 14
SP - 143
EP - 157
JO - Macromolecular Theory and Simulations
JF - Macromolecular Theory and Simulations
IS - 3
ER -