The interphase region widely exists in polymer-based nanocomposites, which affects the dielectric properties of the nanocomposites. General models, such as the Knott model, are often used to predict the dielectric constant of nanocomposites, while the model does not take the existence of interphase into account, which leads to a large deviation between the predicted results and the experimental values. In this study, a developed Knott model is proposed by introducing the interphase region and appropriately assuming the properties of the interphase. The modeling results based on the developed model are in good agreement with the experimental data, which verifies the high accuracy of the development model. The influence of nanoparticle loading on the effective volume fraction is further studied. In addition, the effects of the polymer matrix, nanoparticles, interphase dielectric and thickness, nanoparticle size and volume fraction on the dielectric properties of the nanocomposites are also investigated. The results show that polymer matrix or nanoparticles with a high dielectric and thick interphase can effectively improve the dielectric properties of the materials. Small size nanoparticles with high concentrations are more conducive to improving the dielectric properties of the nanocomposites. This study demonstrates that the interphase properties have an important impact on the dielectric properties of nanocomposites, and the developed model is helpful to accurately predict the dielectric constant of polymer-based nanocomposites.

Due to the relative abundance, long half-life and high mobility of radioactive cesium (Cs), new adsorbents are urgently needed to treat Cs to ensure public health. In this study, a graphene oxide (GO) based adsorbent for Cs(I) adsorption was prepared by 1-aza-18-crown-6 ether modification. XRD, FT-IR, XPS and SEM results showed that the properties of 1-aza-18-crown 6 ether modified GO (18C6-GO) changed dramatically compared with that of raw graphite. The adsorption properties of 18C6-GO for Cs(I) were studied by batch static adsorption experiments. The results showed that the adsorption equilibrium time of 18C6-GO was 20 h. Kinetic study revealed that the adsorption rate of Cs(I) conformed to pseudo-second-order kinetic model. Langmuir adsorption isotherm simulation indicated that the adsorption arises at homogeneous adsorption sites on 18C6-GO. Therefore, crown ether modified GO may have implications for the treatment of wastewater.