Estudo de propriedades reológicas e espectroscópicas de materiais a base de glutamato monossódico e íons terras raras

Abstract

In the present work, syntheses of materials formed from commercial monosodium glutamate (GMS) and rare earth ions (RE) La3+ and Y3+ were performed. The methodology used follows that of previous works, carried out by our research group, which obtained new materials from the reaction between GMS and RE ions. This methodology produced transparent, hygroscopic materials with high viscosity. Initially, the 1:1 ratios between TR (La3+ or Y3+) and the ligand (GMS) were chosen for the structure and properties analyses. Subsequently, a small amount (10%) of europium ion (Eu3+) was added to the materials, with the aim of attributing luminescence to the material. For the characterizations rheology measurements and vibrational spectroscopy (infrared and Raman) were used. Through rheological studies it was observed that the viscosity and elasticity parameters vary as the external stress is applied, characterizing the material as a non-Newtonian fluid. The analysis of frequency as a function of storage modulus (G’) and loss modulus (G’’) determined that for high frequencies the system reaches equilibrium, and for low frequencies the system keeps evolving. In addition, it was noted that despite having elasticity, it is not superior to viscosity, with no freezing point. Therefore, the material cannot be classified as a gel. Infrared spectra and Raman spectra were similar in all samples, with minimal variation in the spectra of materials containing yttrium. This suggests that coordination between RE ions and GMS occurs in a similar way.