Thermal Stability and Decomposition Kinetics of Poly(Methacryloyloxyethyl Trimethyl Ammonium Chloride-Co-Acrylamide)

Poly(methacryloyloxyethyl trimethyl ammonium chloride-co-acrylamide) (P(DMC-AM)), is widely used for various applications under a wide range of conditions. In this work the thermal stabilities and decomposition kinetics of P(DMC-AM) with various intrinsic viscosities, synthesized in our laboratory, were studied by thermogravimetric analysis (TGA) at various heating rates, 5, 10, 20 and 40 K/min, and differential scanning calorimetry (DSC) at 10 K/min, all under a dynamic nitrogen atmosphere. The kinetic parameters were calculated using a model fitting method (Coats-Redfern, CR) and two model-free methods (Kissinger-Akahira-Sunose, KAS and Flynn-Wall-Ozawa, FWO). The result showed that all samples exhibited three steps of mass loss, one for the elimination of the adsorbed water and organic solvents and two for the thermal decomposition of P(DMC-AM). The first decomposition stage for the three samples was in the range of 5% to 45%, the second decomposition stage in the range of 65% to 95% and with 55% conversion separating the first and second decomposition stages. The E values increased with the increasing intrinsic viscosity of the samples. Hence, P(DMC-AM) had good thermal stability and the higher the molecular weight, the better the thermal stability was.