Functionalized TiO₂ Nanoparticles Tune the Aggregation Structure and Trapping Property of Polyethylene Nanocomposites

The interfacial region between a nanoparticle and the polymer matrix is considered to have an important effect on the properties of nanocomposites. In this experimental study, the tuning effects of surface-modified TiO₂ nanoparticles on the aggregation structure and trapping property of the nanocomposites are investigated. The addition of TiO₂ nanoparticles increases the number of spherulites and decreases their sizes. It is also found that TiO₂ nanoparticles can suppress the mobility of chain segments in the interfacial region, suppress crystallization, and reduce the crystallinity, depending on the surface modification and loading levels of nanoparticles. On the basis of the conclusions, the model of a spherulite and the interface is established and the trap distribution of the interface is analyzed according to the results of TSC measurements. It is assumed that there is a strong correlation between traps and the charge transport of nanocomposites, and the mechanism of charge transport is discussed with respect to the results of the volume conductivity measurement. It is believed that this study would provide an important hint to the research of the interface between nanoparticles and the polymer matrix in future research.