The Degradation of P(AM-AMPS) Microspheres Synthesized by Emulsion Polymerization

Anionic polyacrylamide microspheres P (AM-AMPS) were synthesized by emulsion polymerization with 2-acrylamide-2methylpropanesulfonic acid (AMPS) and acrylamide (AM). The degradation experiments were designed at 80 °C. The degradation products of this microspheres were analyzed by scanning electron microscopy, thermogravimetric analysis, infrared spectrum, dynamic light scattering, pH and viscosity measurement. The results showed that, in the first four hours, radical oxidative degradation rapidly broke the main polymer chain of microspheres and decreased the solution viscosity sharply, while the hydrolysis reaction relatively moved slowly and pH kept steady around 2.75. Four hours later, the radical oxidative degradation approached to termination and the hydrolysis reaction of amide began to raise pH by self-acceleration of amide group in acidic condition. The out-layer polymer branch of microspheres degraded in 4 hours and then the inner main chain began to break, resulting in the following faster size decrease. (paper)