Preparation and properties of polyacrylic acid microgel by precipitation polymerization in organic solvent

Polyacrylic acid (PAA) microgels were prepared by precipitation polymerization of acrylic acid in different organic solvent and their properties were analyzed by scanning electron microscope (SEM), rheometer and UV spectrophotometer. The results show that cyclohexane is the appropriate solvent; the pH value of PAA microgel reaches the minimum when the mass fraction of PAA is 0.7%; PAA microgel solution is a kind of pseudoplastic fluid, its viscosity does not vary with the temperature, and reaches the maximum viscosity with pH value of 7, while the microgel changes into the macro gel; the higher the crosslinking degree, the more greatly the viscosity changes with pH value.