S. Penczek et K. Brzezinska, DETERMINATION OF STRUCTURE AND CONCENTRATION OF GROWING SPECIES IN IONIC POLYMERIZATIONS - THE P-31 NMR METHOD, Macromolecular symposia, 85, 1994, pp. 45-64
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.