Study On The Strcture And The Properties Of Polystyrene/tio₂ Nanocomposite

The composites of polymer and inorganic nanoparticle have attracted more and more attention and given rise to their wide applications in many fields. Because of the agglomerated characteristic, 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 through a torque rheometer. The dispersibility of nanoparticles were characterized. The mechanical properties, thermal properties and the dispersibility of nanoparticles in polystyrene matrix were also characterized and discussed by using SEM, TEM, XRD, XPS and FT-IR. 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, and the density of the–C=O and -O-H groups decreased on the surface of nano-TiO₂. The polarity and the aggregation of nano-TiO₂ reduced, but the dispersibility and thermal weight-loss percentage of nano-TiO₂ increased compared with pure nano-TiO₂. The crystal structure of nano-TiO₂ is anatase.The impact strength, tensile strength and elongation at break of the nanocomposites increased and then decreased, but Young's modulus increased with the increasing of nano-TiO₂ content, and the mechanical properties of polystyrene were enhanced though doping nanoparticles at lower loading. The mean size of nano-TiO₂ was less than 100nm, and nano-TiO₂ showed a homogeneous dispersion in polystyrene matrix. Composite materials revealed higher thermal stability. The studies of thermal decomposition kinetics indicated that the speed of thermal decomposition decreased and activation energy of thermal decomposition increased compared with pure polystyrene.