Study On Functional Polymer Matrix Nanocomposites

It prepared polymer based functional nanocomposites by melt compounding in this paper. Functional polypropylene nanocomposites were processed with multiwalled carbon nanotubes (MWNTs) as the electrically conductive component and barium titanate (BT) spherical nanoparticles as the ferroelectric component. It hopes that reducing the MWNTs content and the percolation threshold via the volume-exclusion effect between MWNTs and BT. In addition, from the percolation power law, dielectric permittivity can be enhanced remarkably near the percolation threshold. It resolves the problem of high BT content, which can damage the mechanical property of the nanocomposites. Adding high content partical, the dispersion become the key factor to effect the property of the nanocomposites. So it is necessary to modify the surfaces of partical.To make PP electrically conductive, more than 3 wt% MWNTs is required. The addition of 40 wt% BT enhances the electrical conductivity of the PP/MWNTs nanocomposites owing to their volume-exclusion effect. Modification of either MWNT or BT surfaces with titanate coupling agent further improves the electrical conductivity of the PP/MWNTs/BT ternary nanocomposites. Also, by simultaneously using modified MWNTs and modified BT,2wt% MWNTs are sufficient to make the PP/MWNT/BT nanocomposites electrically conductive. In addition, the incorporation of MWNTs greatly increases the dielectric permittivity of PP/BT nanocomposites. However, to retain a low dielectric loss, the MWNTs loading should be slightly less than that at the percolation threshold of the nanocomposites. Adding 2wt% MWNTs, the dielectric permittivity of PP nanocomposites with 40 wt% m-BT is about 28, which is 3 times that of its unmodified counterpart and 7 times that of neat PP. The inorganic particle also has better thermal conductivity, which can be used to prepared the thermal materials. This paper discuss the effect of MWNTs and BT on the thermal conductivity of the PP matrix. It is shown that the adding the inorganic particle actually improve the thermal conductivity of the composites. More better thermal conductive network can be formed due to their volume-exclusion effect. Afer modification, the thermal conductivity of the composites decrease due to the phone scattering.