Study On Preparation And Properties Of Polystyrene/TiO₂ Nanocomposites

Polymer/inorganic Nanoparticle Composites (PNCs) have attracted more and more attention and given rise to their wide applications in many fields, which combine the excellent properties of inorganic compounds, organic compounds and nanometer-sized materials. However, inorganic nanoparticles cannot exert nanometric effect to full extent because of the agglomerated characteristic. So lowering the interfacial energy of nanoparticles, weakening interfacial polarity of nanoparticles and improving compatibility between nanoparticles and polymer, become the most important technological problem for composite materials.The nano-TiO₂ was modified with a liquid titanate coupling agent in the paper. The polystyrene/TiO₂ nanocomposites were prepared by the melt-blending method. The melt-blending process was discussed with a torque rheometer. Some of the properties of midified and unmodified nano-TiO₂ and polystyrene/TiO₂ nanocomposites were characterized by using lipophilicity experiment, fourier transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscope analysis (XPS), rheological experiment, impact tests, and differential thermal and gravimetric analysis (DTA-TG). The results show as follows:After surface modification, the coupling agents of JN-114 induced a change of the nano-TiO₂ surface from hydrophilic to hydrophobic. The content of C element increased and P element appeared, meanwhile, the density of the -O-H groups decreased on the surface of nano-TiO₂, and the thermal weight-loss percentage of nano-TiO₂ increased compared with bare nano-TiO₂. It indicates that the coupling agents have reacted with the hydroxyl groups on the surface of TiO₂.The impact strength of the nanocomposites was obviously changed after filling the modified or unmodified nano-TiO₂, and the impact strength of the nanocomposites was increased and then decreased with increasing of nano-TiO₂ content. Surface modification of nano-TiO₂ generally yielded nanocomposites of higher impact strength than unmodified system. The polystyrene/TiO₂ nanocomposites had higher thermal stability compared to virgin PS through DTA-TG.A formula of inorganic particles dispersed in polymer was revised and checked. It provided theoretical guidance for controlling nano-TiO₂ dispersed in PS by adjusting dispersion time.