FUNCTIONALIZED INITIATORS FOR GROUP-TRANSFER AND METAL-FREE ANIONIC-POLYMERIZATION FOR THE SYNTHESIS OF MACROMONOMERS - OVERVIEW AND NEW RESULTS

Vinylphenyloxy- and allyloxy-substituted silyl ketene acetals are presented as new functionalized initiators for group transfer polymerization (GTP). All initiators initiated GTP of butyl acrylate in tetrahydrofuran with tetrabutylammonium cyanide as catalyst to yield butyl acrylate macromonomers with number-average molecular weights somewhat lower than those calculated for an ideal living polymerization and with polydispersities of about 1,8-2,6. For the metal-free anionic polymerization, functionalized initiators were obtained introducing allyloxy and vinylbenzyl groups into tetrabutylammonium diethyl malonate. Both compounds initiated a very rapid polymerization of butyl acrylate in tetrahydrofuran with high monomer conversion. The number-average molecular weights of the macromonomers, produced in a semi-batch procedure, reached nearly theoretical values, the polydispersities were about 1,2. In all macromonomers the functionality with respect to terminal vinyl and allyl groups was near one, so that they can be used with other monomers to form graft copolymers, e.g., in a free-radical polymerization.