Dielectric Response of PVC and LDPE Nanocomposites Upon Functionalization of Their Containing Nanoparticles

The impact of nanoparticles surface chemistry on the dielectric response of polyvinyl chloride (PVC) and low density polyethylene (LDPE) based nanocomposites is reported here. The nanoparticles used in this study were titania (TiO2) nanoparticles whose surfaces were functionalized with amino silane as coupling agents. The role of functionalization is to ensure the dispersion of the nanoparticles by reducing their surface energy to be compatible with the used polymers. Nanocomposites containing 0.5% weight fraction of nanoparticles, either functionalized or un-functionalized, have been prepared with solvent-casting method. They were characterized using Fourier transfer infra-red spectrophotometer (FT-IR). Moreover, their surface morphology was studied with the aid of field emission scanning electron microscopy (FE-SEM). Then, the dielectric parameters such as; the relative permittivity (ε_r), dielectric loss (tan δ) and AC, and DC breakdown strength under sphere-sphere electric fields were measured. The obtained data showed reasonable improvement in the electrical insulation properties of the polymers under study especially with using functionalized nanoparticles. This was explained in terms of the good interaction built at the interface of functionalized nanoparticles with the polymeric chains. Furthermore, the improvements in electrical properties of LDPE nanocomposite samples are much better than that of PVC nanocomposites at the same conditions.

I. Introduction

Recently, there was a great attention among high voltage researchers to develop nanocomposite materials for dielectric applications. This is because nanotechnology offers new and advanced polymer base composites with significant improvements in their electrical, mechanical and thermal properties [1].