Synthesis and rheology of methacrylic acid-ethyl acrylate crosslinked polymers

The rheological behaviour of methacrylic acid-ethyl acrylate copolymers (MAA 61.9–78.5 mol%) and terpolymers with two crosslinking agents, i.e. ethylene glycol dimethacrylate (EGDM, 0.23–4.83 mol%) or N, N′-methylene bisacrylamide (MBAM, 0.29–1.48 mol%) has been studied. The effect of pH, shear rate, solid content of the solution, and the addition of electrolyte on the viscosity has been reported. As the viscosity is a function of neutralization of carboxylic acid groups, it was found to be highly dependent on pH. Addition of electrolytes (0.5–1.5%) led to a drastic drop in the viscosity. The influence of different crosslinking agents on the viscosity was also studied and N, N′-methylene bisacrylamide was found to be more efficient than ethylene glycol dimethacrylate. The gel content of the crosslinked polymers was determined to obtain an idea of the degree of crosslinking of the polymers.