2000 Volume 11 Pages 47-52
Measurement of polymerization degree of condensed phosphates was examined by solid-state NMR. Broad peaks of the NMR of end- and middle-PO4 groups of condensed phosphates were observed at about 1 and-20 ppm, respectively. The NMR. peak area ratio (Ro) of middle-PO4 group to end-PO4 group has the following relation with the polymerization degree (n) of polyphosphate:
Ro (middle-PO4/end-PO4)=(n-2)/2 Calculated polymerization degrees of polyphosphates agreed well with measured ones and it is found that the solid-state NMR technique is useful to the measurement of polymerization degree of water-insoluble solid-state condensed phosphates having a chain structure.
