CHARACTERIZATION OF HIGH CHARGE-DENSITY AMPHOLYTIC COPOLYMERS PREPARED BY MICROEMULSION POLYMERIZATION

A series of copolymers of sodium 2-acrylamido-2-methylpropanesulfonate (NaAMPS) and 2-methacryloyloxyethyltrimethylammonium chloride (MADQUA T) prepared by microemulsion polymerization was characterized by means of several techniques. After dialysis, the samples self-neutralize wi th formation of monomer pairs in the copolymer. The molecular weights determined by light scattering are high (greater-than-or-equal-to 10(7 )) and were found to be relatively unaffected by monomer feed ratios. The copolymer microstructure was calculated from the reactivity ratios and compared to that obtained for copolymers synthesized in aqueous s olution. The microemulsion polymerization process yields copolymers mo re homogeneous in composition (r(A)r(B) congruent-to 1.6) than those o btained by polymerization in solution which have a strong tendency to alternation (r(A)r(B) congruent-to 0.05). These differences are discus sed in terms of microenvironment and polymerization mechanisms.