Surface modification of iron particles with polystyrene and surfactants under high-energy ball milling

Metal–polymer composites are widely used in many applications including efficient microwave absorbing materials. Interface makes up a great fraction in the composite bulk and may significantly affect the functional properties of the composite. In this work, we have modified the surface of iron particles with polystyrene and fluorine-substituted/alkyl carbon acids by wet mechanochemical treatment. The study was performed by means of Fourier-Transform Infrared (FT-IR) spectroscopy, Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). It is shown that wet mechanochemical treatment is accompanied by chemisorption of the surfactant molecules on the iron particle surface through the formation of the carboxylate derivatives and catalytic dehydrogenation resulting in the formation of condensed polyaromatic structures. Surface modification of particles with polystyrene is observed in all cases regardless of the presence and type of surfactant in the milling environment. Stable binding of polystyrene with the particle surface is achieved by different ways, including binding through the oxygen-containing groups, covalent bonding with the polyaromatic structures and/or tails of the chemisorbed fluorine-substituted acid. As-formed organic layers stabilize the metal particles preventing them from oxidation and agglomeration and increase their chemical compatibility with polymer matrices in subsequent fabrication of the metal–polymer composites.