Nuclear magnetic relaxation of protons in “polyantimonic acid–phosphate” composites

The results of studying MeH 2 PO 4 (Me = K, Na)/Sb 2 O 5 · 2.7H 2 O composites using the pulsed NMR spectroscopy technique at the temperatures of 20–140°C are presented. The contribution of interfaces, a subsystem formed due to interaction between the components of the composite, is identified in the signals of transverse magnetization decay. Protons near the interfaces are in two states, mobile and bound, and the fraction of mobile protons increases with the temperature, as all protons prove to be in the mobile state at the temperatures above 80°C. The composition of the interface is determined by the ion exchange reaction between components and is close to phosphoric acid. The obtained results explain the observed increase in conductivity of composites as compared to pure components.