Anisotropic Reinforcement of Nanocomposites Tuned by Magnetic Orientation of the Filler Network

摘要

We present a new material which displays anisotropic and mechanicalproperties tuneable during synthesis under magnetic field. It is formulated bymixing aqueous suspensions of polymer nanolatex and magnetic nanoparticles,coated by a thin silica layer to improve their compatibility with the polymericmatrix, followed by casting. The magnetic properties of these nanoparticlesenable their pre-orientation in the resulting nanocomposite when cast undermagnetic field. Detailed insight on dispersion by Small Angle NeutronScattering (SANS) shows chainlike nanoparticle aggregates aligned by the fieldon the nanometer scale. Applying strain to the nanocomposite parallel to theparticle chains shows higher mechanical reinforcement, than when strain istransverse to field. . SANS from strained samples shows that strain parallel tothe field induce an organization of the chains while strain perpendicular tothe field destroys the chain field-induced ordering. Thus improved mechanicalreinforcement is obtained from anisotropic interconnection of nanoparticleaggregates.