Organoclay-epoxy nanocomposites modified with polyacrylates: The effect of the clay mineral dispersion method

• Improved clay dispersion by previous in situ polymerization of acrylate monomer
• Intercalated/exfoliated structures of clay in epoxy-ternary nanocomposites
• Organoclay dispersion confirmed by SAXS and TEM measurements
• Epoxy-based ternary nanocomposites with improved impact resistance and stiffness
• Higher thermal stability for epoxy networks with acrylate copolymer and clay

Organically modified montmorillonite (OMt) was employed to prepare clay/epoxy/acrylate polymer ternary composites. Two different procedures were used for the clay mineral dispersion: i) OMt was dispersed in an epoxy matrix previously modified with acrylate polymers or ii) the clay mineral was swollen in the acrylate monomers and the monomer was in situ polymerized followed by dispersion in the epoxy matrix. For the acrylate polymers, poly(methyl methacrylate) (PMMA) or a methyl methacrylate-co-2-ethylhexyl acrylate copolymer (PMMA-co-PEHA) were used. The nanostructure of the corresponding hybrid materials was investigated by X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The combination of these techniques confirmed the improved dispersion of the OMt in the thermosetting networks prepared by using the previous polymerization of acrylate monomers on the swollen clay mineral. Also this method resulted in ternary epoxy-based nanocomposites with outstanding impact resistance, higher storage modulus and improved thermal stability.