Expanding the Scope of Group Transfer Polymerization Using N-Heterocyclic Carbenes as Catalysts: Application to Miscellaneous (Meth)acrylic Monomers and Kinetic Investigations

Abstract

1,3-Bis(di-isopropyl)imidazol-2-ylidene (1) and 1,3-bis(di-tert-butyl)imidazol-2-ylidene (2), which are N-heterocyclic carbenes (NHCs) are shown to catalyze the solution group transfer polymerization (GTP) of miscellaneous monomers in a controlled fashion at room temperature, in the presence of 1-methoxy-2-methyl-1-trimethylsiloxypropene (MTS) as initiator. The ability of seven distinct monomers, methyl methacrylate (MMA), tert-butyl acrylate (tBA), n-butyl acrylate (nBA), N,N-dimethylaminoethyl acrylate (DMAEA), N,N-dimethyl acrylamide (DMA), N,N-dimethylaminoethyl methacrylate (DMAEMA), and methacrylonitrile (MAN) to polymerize via GTP by NHC catalysis has been evaluated. The first-order kinetic plots, that is the evolution of ln[M]0/[M] versus time, systematically deviate from linearity, with the noticeable exception of GTP of DMA. A direct dependence of the rate of GTP on the concentration in MTS initiator is observed in the case of tBA carried out in THF, that is, the rate of polymerization increases...