Thermal behavior and morphological properties of novel magnesium salt-polyacrylamide composite polymers

Magnesium salt-polyacrylamide composite polymers have been prepared by blending magnesium chloride and magnesium hydroxide, respectively, with polyacrylamide aqueous solution. The thermal behavior of the dried magnesium salt-polyacrylamide composite polymers has been studied. Differential scanning calorimetric (DSC) analysis and thermal gravimetric analysis (TGA) were carried out to investigate the changes of the composite polymers' behavior with temperature. The kinetics of the thermal decomposition of magnesium salt-polyacrylamide composite polymers was investigated over temperature range of 35-800°C with three heating rates of 10, 20, and 40°C/min under nitrogen atmosphere. Flynn and Wall's model was usedto determine the activation energies of thermal decomposition for magnesium salt-polyacrylamide composite polymers. The activation energies needed to decompose 50 wt% of magnesium hydroxide-polyacrylamide (MHPAM) composite polymer ranged from of 28.993-174.307 kJ/mol which are higher than the values for magnesium chloride-polyacrylamide (MCPAM) composite polymer (21.069-39.412 kJ/mol). Therefore, MHPAM composite polymer has a better thermal stability compared with MCPAM composite polymer. The morphological properties of magnesium salt-polyacrylamide composite polymers were studied using scanning electron microscopy (SEM). Energy-dispersive X-ray (EDX) spectroscopy was used to determine the composition of the chemical elements.