The theoretical study on anionic polymerization mechanism of maleimide: Chain propagation by p‐π conjugation process

Abstract

AbstractA complete research on the mechanism of the anionic polymerization of maleimide was performed, not only including the chain initiation, but the propagation as well. The density functional theory method is employed to investigate the reaction pathway using 6‐311+G* basis set, and the Onsager model is also applied to imitate the effect of solvent on the structures and thermodynamic functions of the key steps. It is found that the initiation starts with a nucleophilic reaction, in which the key transition state shows a π‐complex structure. In contrast, the calculated chain propagation (both dimer and trimer process) employs a p‐π conjugation chain propagation mechanism (p‐π CCPM), characterized by the formation of p‐π conjugation orbital between the chain terminal C atom and monomer CC double bond. This mechanism is in good agreement with the frontier molecular theory and the principle of conservation of molecular orbital symmetry. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008