Synthesis in microemulsion and characterization of low charge density ampholytic terpolymers

High molecular weight and low charge density ampholytic terpolymers based on acrylamide (AM), as a neutral monomer, and sodium 2‐(acrylamido)‐2‐methylpropanesulfonate (NaAMPS) and [2‐(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT) as charged monomers have been prepared by a microemulsion polymerization technique. An optimization of the process for the selection of the different components of the microemulsion has been achieved by applying criteria based on the hydrophile‐lipophile balance (HLB) and cohesive energy ratio concepts. Composition‐conversion curves were determined for samples containing different monomer feeds. The drifts observed in the terpolymer compositions with conversion were compared to those calculated from the reactivity ratios determined in binary copolymerizations performed in solution and in microemulsion. The results show that the reactivity of the monomers in ternary systems depends on the ionic strength, i.e. on the monomer feed composition.