Analysis of living tert-butyl methacrylate oligoanions in tetrahydrofuran by NMR spectroscopy, viscosity and light scattering

Previous kinetic studies concluded on the aggregation of the anionic chain ends of living tert-butyl methacrylate oligomers [PtBMA(-), Li+] in THF at low temperature. This aggregation has been confirmed by viscosimetry, light scattering and gradient field NMR techniques in a range of temperature fro m 253 K to 298 K. These techniques have been systematically used for the an alysis of both the living oligomers and the same chains recovered after hyd rolysis of the anionic end groups. The structure of the growing anionic spe cies was analyzed by means of C-13 and Li-7 NMR spectroscopy. C-13 NMR requ ired the selective labeling of the last monomer units by C-13 atoms.