La formation de complexes entre des copolymères à blocs polystyrène-poly(oxyde d'éthylène) et le dodecylsulfate de sodium (SDS) est mis à profit dans un procédé d'agglomération contrôlée de latex de PS et de PVC stabilisés par du SDS. On utilise comme agglomérants des latex « chevelus » de PS et de PVC synthétisés en présence de copolymères PS-POE. La distribution granulométrique de latex agglomérés est étudiée en fonction des proportions des deux types de latex et de leurs taux de couverture en SDS et en POE. Des distributions monomodales de particules agglomérées de taille comprise entre 1 et 40 μm peuvent être obtenues. Pour citer cet article : P. Peter et al., C. R. Chimie 6 (2003).

For polystyrene-poly(ethylene oxide) (PS-PEO) diblock copolymers, as micellar dispersions in aqueous medium, the formation of complexes with anionic surfactants, such as sodium dodecylsulfate (SDS) could be confirmed. The number of SDS molecules fixed per EO unit is close to the values reported for the SDS-PEO homopolymer interaction. Advantage of this type of complexation was taken to develop a controlled agglomeration process for SDS stabilized PS and PVC latexes by using as agglomerants hairy' latexes of PS and PVC that have been synthesized in the presence of PS-PEO block copolymers and that carry therefore a fringe of PEO sequences on their surface. The complexation of SDS by these surface-anchored PEO chains leads to the destabilization of the anionic latex, which has a tendency to precipitate onto the surface of the agglomerant latex. The average particle size and the size distribution of the agglomerated particles were studied as a function of the weight and number ratio of the two types of latexes involved in the agglomeration process, as well as in function of the surface coverage by SDS and PEO respectively. By adjusting these parameters, it was possible to obtain, with an efficiency of almost 100%, latex agglomerates with a monomodal distribution in the size range of 1 to 40 μm. An agglomeration mechanism could be outlined taking into account the complexation capacity and the specific surface of the agglomerating hairy' latex. To cite this article: P. Peter et al., C. R. Chimie 6 (2003).