Study Of Anisotropic Janus Composite Particles Based On Urushiol-rare Earth Chelate Polymer/Polystyrene

Raw lacquer is a natural and renewable material and its performance is superior to synthetic polymers. At present, many researchers focus on the modification of raw lacquer to develop its application further. So far, the Janus composite particles mainly come from synthetic materials, such as polystyrene and methyl methacrylate. Thus, it is a meaningful work to preparation of Janus composite particles containing natural urushiol. In this paper, the anisotropic Janus composite particles based on urushiol(U)-rare earth (erbium, praseodymium, samarium, neodymium, lanthanum and gadolinium) chelate polymer (Re)/polystyrene (PS) were synthesized. Firstly, PS was sulfonated with concentrated sulfuric acid. Then, the sulfonic groups on the surface of PS microspheres absorbed Re3+. Followly, the urushiol-rare earth (URe) coordination compound was formed owing to the reaction between urushiol and Re3+. Subsequently, oxidative polymerization reaction between the unsaturated side chains of urushiol occurred and the URe/PS core-shell composite microspheres were generated. Finally, the Janus composite particles of URe-PS were obtained by the approach of emulsion swelling assisted protrusion and emulsion swelling polymerization. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), infrared spectroscopy (IR), thermal gravimetric analysis (TGA) and near infrared photoluminescence spectroscopy (NIR) were used to explore the structure, composition and property of the URe/PS core-shell composite microspheres and the URe-PS Janus composite particles.It is the key to control thickness of the shell of URe for the swelling process. The thickness of URe shell could be controlled by adjusting the sulfonated time and the polymerizing temperature of urushiol. Due to the outermost orbits of La3+ and Gd3 are empty or half filled, their coordination ability are weak, so it is difficult for ULa or UGd to be coated on the surface of PS effectively. The kind of monomer, the usage of monomer and swelling time had effects on the swelling behavior during emulsion swelling assisted protrusion. The redox initiator is better than organic initiator for the emulsion swelling polymerization. The URe-PS Janus composite particles possess the characteristics of urushiol and rare earth, which were expected to be applied in the anisotropic functional polymeric material.