Thermal Degradation of Carboxymethyl Cellulose (CMC) in Saline Solution for Applications in Petroleum Industry Fluids

This work aims to evaluate the thermal degradation of carboxymethyl cellulose (CMC) in solution in the presence of salt, as well as to study the correlation of the rheological behavior of these solutions with exposure to temperature. Step 1 involved characterizing powdered low- and high-viscosity CMC using SEM, FTIR, TGA/DrTGA, and DSC. In step 2, CMC solutions in fresh and saline water were characterized by TGA/DrTGA and viscosity tests. Step 3 exposed saline solutions to 70–150 °C for varying times, followed by TGA/DrTGA and viscosity analyses. There were no significant differences in the thermal degradation of LV and HV CMC, nor in terms of the physical state of the polymer. The results demonstrate that the use of CMC necessitates a combined analysis of thermal degradation and rheological behavior.