(Fig. 12) two signals at 12 ppm and 28 ppm were observed,
which come from transformation of AlPi at high temperatures. They
were assigned to aluminium phosphonate and phosphate, respectively.
An additional signal at 47 ppm indicates that aluminium
phosphinate still remained in the residue. It should be noted that the
signal at 28 ppm corresponds to the resonance at 38 ppm on the 27Al spectrum, indicating an AlPO4 structure. All signals are broad,
which confirms the amorphous character of the residue. Those results
support the information obtained from 27Al MAS NMR.
The introduction of MH and ZB resulted in more complex 31P
NMR spectra. To distinguish and to assign signals, the 31P(27Al)
TRAPDOR NMR technique was used. For TPE-S/AlPi/MH