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 (εr), 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.