DETERMINATION OF STRUCTURE AND CONCENTRATION OF GROWING SPECIES IN IONIC POLYMERIZATIONS - THE P-31 NMR METHOD

The quantitative transformation of the ionic growing species (approxim ately approximately approximately ) into the P atom containing end-gr oups (approximately approximately approximately P) allows to determine by P-31 NMR their structures and concentrations, down to 10(-4) mol.L -1, or even lower with a further progress of the NMR equipment: [GRAPH ICS] The P atoms are exclusively located at the chain ends, the known excess of the reagent ''P'' being used as an internal standard. The ch emical shifts of thus prepared chain ends, when compared with models, give information on the chemical structure of the parent active specie s. This paper reviews the earlier work on ionic ring-opening polymeriz ation and more recent work, concerning cationic and anionic vinyl poly merization, particularly polymerization of vinyl ethers, styrene, meth acrylates and some diene monomers. In the polymerization of vinyl ethe rs the stereochemistry of the chain ends was studied; it has also been shown, that chemical shift changes with the polymerization degree; th us the first addition products could separately be observed.