“…Some strong signals can be observed corresponding to the stretching vibrations of different bonds: 2880 cm −1 (C–H stretch), 1278 and 1240 cm −1 (C–O–C stretches), and 1097 cm −1 (C–O stretch) [ 46 , 47 , 48 ]. On the other hand, in the TPP spectrum ( Figure 2 II(c)), it is possible to observe absorption bands at 1208 cm −1 belonging to the stretching vibrations of P═O, at 1137 cm −1 symmetric and antisymmetric stretching vibrations of the PO 2 group, at 1094 cm −1 symmetric and antisymmetric stretching vibrations of the PO 3 group, and at 889 cm −1 antisymmetric stretching vibrations of the P–O–P bond [ 49 , 50 ]. When d and e spectra belonging to the hydrogels prepared are compared with the a–c spectra of the initial components, it is clearly noted that although the characteristic signals of both initial polymers are observed, their largest amount corresponds to PF, which has the highest proportion in the final material.…”