Hemiesters and hemiamides of maleic and succinic acid: Synthesis and application of surfactants in emulsion polymerization with styrene and butyl acrylate

Hemiesters and hemiamides of maleic acid with different chain lengths of th e hydrophobic alkyl group (R = C8H17, C10H21, C12H25, C16H33) have been syn thesized and used as surfactants in the emulsion polymerization of styrene and butyl acrylate. The same polymerization experiments were also carried o ut using nonreactive surfactants with an analogous succinic structure. The chemical structure of the surfactants was confirmed by 1H nuclear magnetic resonance. The melting point and critical micelle concentration of the reac tive surfactants described herein were measured. All of the surfactants stu died provided good stability of styrene/butyl acrylate latexes, when compar ed with a reference latex of a styrene/butyl acrylate copolymer prepared wi th a surfactant sodium dodecyl sulfate. The amount of surfactant grafted onto the particles of the final latex was estimated by conductimetric titration. Between 33 and 68% of surfactant use d in emulsion polymerization was found on the surface of latex particles. E lectrolyte addition at high concentration and freeze/thaw cycle cause flocc ulation of latexes. Copyright (C) 1999 John Wiley & Sons, Ltd.