| 摘要 |
The present invention relates to a novel, rapid initiating mechanism for anionic, ring-opening polymerization of lactones by means of latent initiators based on N-heterocyclic carbene compounds which can be thermally activated, such as, in particular, N-heterocyclic carbene-CO2, carbene-CS2 and carbene-metal compounds (NHC). Molecular weights of 2000 to more than 20 000 g/mol and narrow polydispersities can thus be realized using the novel initiating mechanism for the polymerization of &egr;-caprolactone. The polymerizations may be carried out either without solvent or in solution. Compounds of this type are thermally latent and initiate a polymerization to give polylactones on heating, sometimes in high yields up to a level of quantitative conversion, while a reaction does not occur at room temperature. The polydispersity and molecular weight of the polylactone can be adjusted by selection of the initiator and the reaction conditions. |
