The current study is to investigate the influence of inserting chemically modified
titanium oxide (TiO2) nanoparticles on the dielectric and mechanical properties of the
commercial compound Polyvinyl Chloride (PVC) used in insulating power cables. The
surface modification of TiO2 nanoparticles was performed using vinyl silane coupling
agent after activating their surfaces with methane-sulfonic acid. The PVC pellets were
first dissolved using suitable solvent. Then, PVC/TiO2 nanocomposites, with different
loadings of nanoparticles, were synthesized with the aid of ultra-sonication for better
dispersion of nanoparticles. The morphology of the prepared nanocomposites was
studied by field emission scanning electron microscopy (FE-SEM), and their
mechanical properties were studied by performing tensile test at speed of 50 mm/min.
The results showed that the insertion of functionalized nanoparticles is able to increase the tensile strength and the Young's modulus of the prepared samples, however it
decreases their elongation. The dielectric properties, such as dielectric constant and dielectric loss, were also studied in a range of frequencies between 20 Hz and 1 MHz.
Moreover, AC breakdown voltage of prepared samples was measured under uniform and semi-uniform field, and then, AC dielectric strength was evaluated using Finite Element Method (FEM) for semi-uniform field. For further evaluation, DC breakdown
voltage was also measured under uniform field. PVC/TiO2 nanocomposites with functionalized TiO2 exhibited better dielectric properties compared to that with unfunctionalized
TiO2 or that of base PVC. This may be attributed to the low surface
energy of the functionalized TiO2 nanoparticles that prevented the agglomeration of nanoparticles and restricted the mobility of polymeric chains. |
