Innovative Method for Laponite Encapsulation into Polymer Latex Particles by Clay Cluster-Seeded Emulsion Polymerization

Laura Delafresnaye (1) , Pierre-Yves Dugas (1) , Muriel Lansalot (1) , Elodie Bourgeat-Lami (1)

1 C2P2 - Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265

We herein report an innovative pathway for the encapsulation of Laponite® platelets into polymer nanoparticles via free radical polymerization in heterogeneous aqueous medium. Hydrophobization of the Laponite® platelets was performed via double functionalization of the clay basal surfaces and edges by a cationic surfactant and an organosilane, respectively. The hydrophobized platelets were then dispersed in toluene and ultrasonicated with an aqueous solution of an anionic surfactant to form clay-loaded toluene droplets. The droplets were subsequently transformed into clusters by toluene evaporation and finally encapsulated into polymer latex particles using a seeded-emulsion polymerization process. Two different copolymers were synthesized: poly(styrene-co-methyl acrylate), as a model system, and poly(vinylidene chloride-co-methyl acrylate), a specialty film-forming copolymer. Stable composite particles with a diameter ranging from 150 to 180 nm were obtained for both copolymers. TEM analysis showed that the Laponite® clay platelets were successfully encapsulated into the polymer latex particles. The films cast from the composite suspensions of poly(vinylidene chloride-co-methyl acrylate)/clay particles showed spherical inclusions of clay tactoids dispersed within the polymer matrix. 2

Domaines: Polymères

Laura Delafresnaye, Pierre-Yves Dugas, Muriel Lansalot, Elodie Bourgeat-Lami. Innovative Method for Laponite Encapsulation into Polymer Latex Particles by Clay Cluster-Seeded Emulsion Polymerization. Macromolecules, 2019, 53 (1), pp.39-50. ⟨10.1021/acs.macromol.9b02190⟩. ⟨hal-02493712⟩